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BQ4802YDWG4 - Parallel RTC with CPU Supervisor | Texas Instruments
The Texas Instruments BQ4802YDWG4 is a Y2K-compliant parallel real-time clock with a CPU supervisor and external NVSRAM control, operating from a 5 V supply in a 28-pin SOIC package. It provides time-of-day tracking, century-based calendar functions, BCD-formatted clock data, and a parallel microprocessor interface. The verified product data identifies a 28-SOIC package measuring 0.295 inches, or 7.50 mm, in width, with surface-mount construction. A real-time clock is a Clock & Timing integrated circuit that maintains calendar time independently of the host processor. The BQ4802Y family combines the RTC function with CPU supervision and external nonvolatile SRAM control, allowing a system to detect power interruptions and preserve critical state when the primary supply fails. This integration is useful in industrial controllers, embedded systems, data-acquisition equipment, and other designs that require reliable wall-clock time plus power-failure control. The BQ4802YDWG4 uses a parallel interface and BCD clock format, as shown in the verified distributor and datasheet listings. Its Y2K-compliant design provides century-based calendar information, while the CPU supervisor supports system monitoring and reset-related control functions. External NVSRAM control is an important distinction from basic RTC-only devices because the IC can coordinate backup or nonvolatile memory behavior during power transitions. Exact operating voltage limits, current consumption, oscillator accuracy, temperature range, and supervisor timing values were not supplied in the verified data and require confirmation from the manufacturer datasheet. Typical implementation places the BQ4802YDWG4 beside the host processor, backup battery, external NVSRAM, and system reset circuitry. The parallel bus allows the processor to read calendar and time registers during normal operation, while the supervisor provides a hardware path for power-failure detection. Designers should verify signal levels, battery backup behavior, reset timing, and NVSRAM interface requirements against the complete Texas Instruments datasheet before production release. Because the part is a clock-and-timing IC rather than a power semiconductor, SOA data is not applicable. For BQ4802YDWG4 sourcing, compare authorized inventory, package variant, datasheet availability, and lifecycle status rather than relying only on a generic cross-reference result. The verified listing from Heisener reported 3,520 pieces at a reference unit price of $7.8255, while Rochester Electronics reported the part in stock; these figures are distributor observations rather than a universal market price.
BQ4802YDWR - 5V Parallel RTC with Supervisor | TI (Tape & Reel)
The Texas Instruments BQ4802YDWR is a 5 V parallel real-time clock and calendar IC with CPU supervisor in a 28-pin SOIC package. It counts seconds through centuries in BCD format, supports time-of-day and calendar functions, and includes an on-chip battery-backup switchover circuit with nonvolatile control for external SRAM. According to the verified Texas Instruments product-page description, the bq4802Y is intended as a low-power microprocessor peripheral for systems requiring dependable timekeeping and power supervision. A real-time clock is a specialized digital integrated circuit that maintains time independently of the system processor. The RTC category includes clock-and-calendar devices, calendar ICs, and real-time clock modules; within the broader semiconductor hierarchy, these devices support embedded control, data logging, industrial timing, and power-management functions. The BQ4802YDWR combines this timekeeping role with a CPU supervisor, reducing the number of separate components needed in a system that must monitor supply voltage or reset the processor during a power event. The verified feature summary identifies 5 V operation for the bq4802Y version, century-based counting in BCD, battery-backup switchover, nonvolatile control for external SRAM, and less than 500 nA clock operating current in backup mode. The 28-SOIC package measures 0.295 inches, or 7.50 mm, in width according to the distributor listing. The parallel interface is intended to connect the RTC to a microprocessor bus, while the supervisor function supports system-reset and power-monitoring designs. The BQ4802Y family is identified by Texas Instruments as suitable for fax machines, copiers, industrial control systems, and point-of-sale equipment. Those applications commonly require calendar-level timekeeping, event logging, scheduled operation, and correct behavior after main power removal. Because the verified material does not provide complete electrical timing, accuracy, temperature, or pin-level values, those parameters remain explicitly marked as data-needed rather than inferred. Designers should follow the manufacturer datasheet for pin assignments, recommended backup-cell connection, decoupling, interface timing, and supervisor thresholds. Care should be taken to preserve the parallel-bus signal integrity and to validate battery switchover behavior across the complete system power profile. The low backup current is particularly relevant when the design spends substantial time operating from a primary cell or backup source. This page consolidates verified distributor and manufacturer information, separates known BQ4802YDWR facts from missing datasheet parameters, and explains replacement and sourcing constraints. Because the supplied cross-reference results do not establish a verified drop-in equivalent with complete pin and parameter data, no substitute is asserted as electrically and mechanically interchangeable.
BQ4802YDWRG4 - Y2K Parallel RTC with CPU Supervisor | TI
The Texas Instruments BQ4802YDWRG4 is a Y2K-compliant parallel real-time clock and calendar integrated circuit with CPU supervisor functions, supplied in a 28-pin SOIC package. It combines a century-based time-of-day clock, a calendar, voltage monitoring, processor reset generation, and external nonvolatile SRAM control for industrial and embedded control systems. The verified distributor listing identifies the device as IC RTC CLK/CALENDAR PAR 28-SOIC, and the manufacturer describes the BQ4802Y as a low-power microprocessor peripheral intended for fax machines, copiers, industrial controls, point-of-sale equipment, and other embedded systems. The BQ4802Y family monitors its supply voltage with a temperature-compensated reference and comparator, generating an interrupt warning and then a microprocessor reset when the supply becomes out of tolerance. The parallel interface allows a host processor to read and write the RTC through address and data lines rather than a serial bus. This makes the device useful in systems where the host already has a parallel bus but lacks a dedicated wall-clock timebase. The century-based calendar addresses year-2000-related date rollover concerns in systems that must retain a full date across power loss or long service intervals. The CPU supervisor function adds system-reset and warning capability, allowing firmware to respond before an out-of-tolerance supply causes an uncontrolled reset. External nonvolatile SRAM control is another distinguishing feature. Systems using battery-backed SRAM can place the RTC and memory-control functions under one coordinating controller rather than implementing separate timekeeping and retention supervision. The integration reduces the number of discrete functions required, although the battery backup, crystal connection, supply bypassing, and supervisor reset behavior still require careful design review. The verified BQ4802YDWRG4 listings specify a 28-pin SOIC measuring 0.295 inch, or 7.50 mm, in width. Heisener reports 5,376 pieces in stock and a unit price of $4.5050 as of 2026-10-28, while LCSC lists the part from $2.2824. Lead time on the Heisener listing is marked to be confirmed, so production schedules should not rely on the stated May 16 to May 21 estimated delivery window. This page distinguishes the BQ4802Y from the lower-voltage BQ4802L family, identifies verified same-package options for design review, and summarizes application, sourcing, and replacement considerations beyond a distributor stock listing. Because the retrieved data does not include a complete manufacturer pin table, electrical limits, or a manufacturer cross-reference list, unavailable parameters are explicitly marked as DATA_NEEDED rather than inferred.
BQ4802YPW - Parallel RTC with CPU Supervisor | Texas Instruments
The Texas Instruments BQ4802YPW is a Y2K-compliant parallel real-time clock with CPU supervisor and external nonvolatile SRAM control, packaged in a 28-pin TSSOP. It combines a time-of-day clock, century-based calendar, and microprocessor supervisory functions in one low-power timing peripheral. The verified distributor description identifies the device as a parallel RTC clock/calendar IC and confirms its 28-pin TSSOP package. A real-time clock is a clock-and-timing IC that maintains time independently of the system processor. The BQ4802YPW belongs to the RTC, clock/calendar, timekeeping, and clock-and-timing hierarchy. Its century-based calendar and external SRAM backup-control capability make it useful in systems that require retained system time or controlled preservation of processor memory during power transitions. The integrated CPU supervisor adds another layer of power-management functionality around a clock peripheral. The main verified features are Y2K-compliant calendar operation, parallel timekeeping, a CPU supervisor, external nonvolatile SRAM control, 5 V VCC operation as identified in the available technical description, and a 28-pin TSSOP package. These features distinguish it from basic RTC devices that provide only seconds, minutes, hours, and date registers. The TSSOP package is intended for compact surface-mount PCB designs, while the parallel interface simplifies connection to compatible microprocessor or embedded-controller buses. The BQ4802YPW is positioned for embedded systems, industrial controllers, data-acquisition equipment, test and measurement systems, and other microprocessor-based products where accurate timekeeping and supervised power transitions are useful. A system designer should verify the exact bus timing, reset behavior, SRAM-control requirements, and electrical limits in the manufacturer datasheet before finalizing a design. The provided search data confirms the product identity and broad functionality but does not provide a complete manufacturer datasheet specification set. The key design consideration is validating the relationship between the RTC, CPU supervisor, and external SRAM backup circuitry. If the system uses battery-backed SRAM, power sequencing and supply rails must be checked against the device's required operating conditions. As with any compact mixed-signal timing IC, PCB layout should preserve clean supply paths and follow the manufacturer's recommended decoupling and pin-routing guidance. This page consolidates verified distributor identification, product classification, package information, and practical sourcing guidance. It also separates confirmed facts from missing electrical details so engineers can make an informed preliminary selection without assuming unverified ratings, prices, or lifecycle claims.
BQ4802YPWR - Parallel RTC with CPU Supervisor | Texas Instruments (Tape & Reel)
The Texas Instruments BQ4802YPWR is a Y2K-compliant parallel real-time clock with CPU supervisor and external nonvolatile SRAM control, packaged in a 28-pin TSSOP. It combines a time-of-day clock, century-based calendar, and microprocessor supervisory functions in one low-power timing peripheral. The verified distributor description identifies the device as a parallel RTC clock/calendar IC and confirms its 28-pin TSSOP package. A real-time clock is a clock-and-timing IC that maintains time independently of the system processor. The BQ4802YPWR belongs to the RTC, clock/calendar, timekeeping, and clock-and-timing hierarchy. Its century-based calendar and external SRAM backup-control capability make it useful in systems that require retained system time or controlled preservation of processor memory during power transitions. The integrated CPU supervisor adds another layer of power-management functionality around a clock peripheral. The main verified features are Y2K-compliant calendar operation, parallel timekeeping, a CPU supervisor, external nonvolatile SRAM control, 5 V VCC operation as identified in the available technical description, and a 28-pin TSSOP package. These features distinguish it from basic RTC devices that provide only seconds, minutes, hours, and date registers. The TSSOP package is intended for compact surface-mount PCB designs, while the parallel interface simplifies connection to compatible microprocessor or embedded-controller buses. The BQ4802YPWR is positioned for embedded systems, industrial controllers, data-acquisition equipment, test and measurement systems, and other microprocessor-based products where accurate timekeeping and supervised power transitions are useful. A system designer should verify the exact bus timing, reset behavior, SRAM-control requirements, and electrical limits in the manufacturer datasheet before finalizing a design. The provided search data confirms the product identity and broad functionality but does not provide a complete manufacturer datasheet specification set. The key design consideration is validating the relationship between the RTC, CPU supervisor, and external SRAM backup circuitry. If the system uses battery-backed SRAM, power sequencing and supply rails must be checked against the device's required operating conditions. As with any compact mixed-signal timing IC, PCB layout should preserve clean supply paths and follow the manufacturer's recommended decoupling and pin-routing guidance. This page consolidates verified distributor identification, product classification, package information, and practical sourcing guidance. It also separates confirmed facts from missing electrical details so engineers can make an informed preliminary selection without assuming unverified ratings, prices, or lifecycle claims.
BQ4802YPWRG4 - Parallel RTC with CPU Supervisor | TI
The Texas Instruments BQ4802YPWRG4 is a parallel real-time clock and calendar IC with CPU supervisor, watchdog timer, alarm, daylight-saving, and leap-year functions. It operates from a 5 V supply, supports a maximum clock frequency of 0.032 MHz, and is packaged in a 28-pin TSSOP measuring 0.173 inches wide and 4.40 mm wide. The BQ4802YPWRG4 also provides interrupt capability and external NVSRAM control. A real-time clock, or RTC, is a clock and timing semiconductor that maintains time-of-day and calendar information independently of the main processor. In the broader hierarchy, an RTC is a clock and timing IC, followed by timer and real-time-clock ICs. Integrating a CPU supervisor with an RTC allows a system to retain calendar information while also monitoring a supply rail and recovering a processor or other circuit when voltage falls outside acceptable limits. The BQ4802YPWRG4 combines several timing and supervisory functions in one package. Its parallel interface supports integration with processors that use a parallel bus, while the integrated clock and calendar provide year, month, day, and time-of-day tracking. The device also includes an alarm, daylight-saving capability, leap-year handling, watchdog-timer support, and external NVSRAM control, reducing the number of separate support components required in embedded equipment. The 5 V supply requirement and 0.032 MHz maximum clock frequency distinguish this device from low-voltage, serial-interface RTC families. A maximum frequency of 0.032 MHz corresponds to 32 kHz, providing a conventional timekeeping reference for the oscillator section. The operating temperature range shown by the distributor data is 0 °C to 70 °C, placing the specified grade in commercial temperature conditions. Typical uses include industrial controllers, embedded processors, data-acquisition equipment, instrument systems, and compact control products that require both continuous timekeeping and supply supervision. Its interrupt output allows a host processor to respond to scheduled events or supervisory conditions, while external NVSRAM control can coordinate retained memory with the RTC. Designers should verify oscillator characteristics, reset behavior, interface timing, interrupt polarity, and the external NVSRAM connection in the manufacturer datasheet before layout. Because the device uses a 28-pin TSSOP, adequate routing clearance and careful ground-return planning are important for reliable clock accuracy and clean supervisor operation. This page combines distributor availability, exact package information, Y2K-compliant parallel RTC positioning, and same-family alternatives with practical design guidance. It helps engineers distinguish the BQ4802YPWRG4 from timer-only ICs and from RTCs that lack the integrated CPU supervisor, watchdog, and external NVSRAM control features.
BQ4822YMA-70 - 8Kx8 NVSRAM RTC Module | Texas Instruments
The Texas Instruments BQ4822YMA-70 is a battery-backed real-time clock and calendar module with 8Kx8 nonvolatile SRAM, watchdog timer, up reset, interrupts, and battery-low warning functions in a 28-pin DIP module. It counts hundredths of a second through years in BCD format, uses RAM-like clock access, and is designed for 5 V-powered systems that need timekeeping plus retained data after power loss. The verified distributor information identifies the package as a 28-DIP module measuring 0.61 inches, or 15.49 mm. A real-time clock is a clock-and-timing integrated circuit that maintains calendar and time information independently of the host processor. This device belongs to the RTC module and nonvolatile data-storage hierarchy, combining a crystal-based timekeeper, 8Kx8 SRAM, power-fail circuitry, and a battery backup path. That combination lets a controller recover timestamp and configuration data after mains or system power is removed. The BQ4822Y family is described as an RTC module with 8Kx8 NVSRAM, watchdog timer, up reset, interrupts, and battery-low warning features. Its RAM-like clock access and industry-standard x 8 SRAM compatibility simplify integration with parallel bus-oriented embedded systems. The verified distributor listings also identify alarm, leap-year, supervisor, and real-time-clock functions, while the listed clock frequency is 0.032 MHz. Typical applications include industrial controllers that must preserve event logs, communications equipment requiring timestamped events, embedded systems with brownout recovery, and battery-backed instrumentation that needs calendar data and retained parameters. The host processor can read and write the module through a parallel interface while the RTC maintains time independently during power loss. Designers should preserve the module’s battery-backed architecture, validate the host bus and interrupt polarity, and check the exact pin assignments against the manufacturer datasheet before layout. The supplied search data confirms the 28-DIP module and 5 V supply description, but it does not provide a complete electrical timing table, so unverified current, accuracy, memory-retention, and temperature values are intentionally not asserted here. This page consolidates the verified distributor identity, package information, functional description, and engineering guidance while separating confirmed facts from unavailable parameters. It is intended to support component selection, data retrieval, comparison planning, and first-pass hardware design review without inventing values absent from the supplied sources.
BQ4832YMA-85 - RTC with 32Kx8 NVSRAM | Texas Instruments
The Texas Instruments BQ4832YMA-85 is a real-time clock module with integrated 32Kx8 nonvolatile SRAM, watchdog timer, CPU supervisor, crystal, power-fail circuitry, and battery-low warning in a 32-pin DIP module. Its verified nominal operating voltage is 5 V, clock frequency is 0.032 MHz, and the package measures 0.610 inches, or 15.49 mm, in length. The device provides RAM-like clock access, parallel clock/calendar functionality, interrupts, and an integrated backup-power-oriented subsystem for systems requiring timekeeping across power interruptions. A real-time clock is a clock-and-timing integrated circuit that maintains calendar and time information independently of the host processor. An RTC module extends the clock-and-timing category by combining timekeeping with nonvolatile memory, supervision, alarm, and power-management functions. In the broader semiconductor hierarchy, the BQ4832YMA-85 belongs to integrated circuits, clock and timing ICs, and real-time-clock modules. Verified features include a 32Kx8 NVSRAM, a watchdog timer, integrated SRAM, a real-time clock, a CPU supervisor, a crystal, a power-fail circuit, and battery-low warning. The device counts hundredths of seconds through years in BCD format, while RAM-like clock access supports system software access to the time and calendar functions. Distributor data identifies the component as a parallel, rectangular, through-hole commercial-temperature device with 32 terminals. The BQ4832YMA-85 is intended for embedded industrial, instrumentation, communications, data-acquisition, and embedded-control systems where a host reset, power interruption, or system clock disturbance must not erase chronological records. Its integrated NVSRAM allows application data to be associated with timekeeping, while the watchdog and supervisor functions support more robust control-loop behavior. The 32-pin DIP package favors through-hole construction and prototype or legacy-system compatibility. Designers should verify the complete pinout, oscillator connection, backup-battery requirements, interrupt polarity, memory organization, and electrical limits against the manufacturer datasheet before layout. Because the verified source data does not provide complete timing, current, temperature, and pin-level specifications, those values require design verification rather than assumption. This page combines verified distributor data, the available datasheet description, application guidance, and engineering-focused procurement context. It is intended to support initial component selection while clearly separating confirmed values from parameters that still require manufacturer-documentation review.
BQ4842YMA-85 RTC with 128Kx8 NVSRAM | Texas Instruments
The Texas Instruments BQ4842YMA-85 is a real-time clock and calendar module with 128Kx8 nonvolatile SRAM, a 32-DIP module package, and integrated timekeeping, memory, supervision, and power-fail functions. Its verified product classification is Clock/Calendar Parallel, with a module body measuring 0.610 inches, or 15.49 mm. The part combines an SRAM-like clock interface, watchdog timing, reset, interrupts, and battery-low warning features into one timing module. A real-time clock is a clock-and-timing IC that maintains calendar and time information independently of the host processor’s main clock. In the broader hierarchy, an RTC belongs to timing ICs, then clock and calendar devices, then semiconductor-based timekeeping systems. Adding nonvolatile SRAM to the same module allows a controller to retain logs, configuration data, calibration values, or event records while the RTC continues tracking time. The verified feature set includes an integrated SRAM, real-time clock, CPU supervisor, crystal, power-fail control circuit, and battery. Search results also describe time counted in hundredths of a second through years in BCD format. The RTC uses RAM-like clock access, while the watchdog, reset, interrupt, and battery-low functions support system monitoring and reliable control of embedded equipment. Because the BQ4842YMA-85 is a parallel-interface device, the host processor must have compatible input, output, and control signals. Its 32-DIP module format favors through-hole assembly and repairable industrial or instrumentation designs rather than compact surface-mount consumer products. The module can be used where persistent records and accurate calendar time are required together, reducing the number of separate timing and memory components. Typical applications include industrial data loggers, instrument panels, metering equipment, communications systems, and embedded controllers. In each case, the RTC supplies timekeeping while the NVSRAM preserves operating data. Designers should verify the complete electrical limits, pin names, crystal requirements, battery behavior, and reset logic against the manufacturer datasheet before layout or firmware development. The main design consideration is integration: the BQ4842YMA-85 can simplify a board by combining timekeeping and retained storage, but it requires correct bus timing and dependable backup power. A BQ4842YMA-85 datasheet search should be used to confirm the device variant’s exact electrical characteristics and package details before committing to a production design. This page combines the verified distributor classification, manufacturer-described features, source links, cross-reference results, and practical integration guidance. It distinguishes verified facts from unavailable parameters so engineers can assess fit without relying on guessed specifications.
BQ4845P-A4 Parallel RTC with CPU Supervisor | Texas Instruments
The Texas Instruments BQ4845P-A4 is a low-power parallel real-time clock and calendar integrated circuit with CPU supervision, watchdog, alarm, and backup-battery functions in a 28-pin DIP package. It tracks time from seconds through a 100-year calendar, connects directly to a 32.768 kHz quartz crystal, and supports a 3 V backup battery. Its backup current is specified below 500 nA in backup mode, helping preserve time and external nonvolatile SRAM information when system power is absent. A real-time clock, or RTC, is a clock-and-timing semiconductor that maintains calendar time independently of the host processor. The BQ4845 combines a time-of-day clock, 100-year calendar, CPU supervisor, watchdog timer, reset control, and nonvolatile-SRAM support in one device. It is intended for legacy embedded systems and equipment that retain time across power interruptions. Key features include direct crystal connection, backup-battery switchover, programmable alarms, leap-year compensation, daylight-saving support, watchdog operation, CPU reset generation, and conditional chip-enable output. The parallel interface allows a host processor to read and write calendar and control information through discrete digital signals rather than a serial bus. A 3 V backup cell powers the timekeeping section and can maintain supported external SRAM data. The device is designed for fax machines, copiers, industrial control systems, point-of-sale terminals, data loggers, and computers. Its DIP format supports through-hole legacy boards and replacement of an existing 28-pin clock-and-calendar footprint. System design must follow the manufacturer’s pin connections and ensure that the crystal, backup source, reset circuitry, and external SRAM support network are correctly connected. Because a DIP package is specified for BQ4845P-A4, do not substitute a surface-mount SOIC variant without confirming the exact package, pin mapping, and board footprint. The product page identifies BQ4845 as available in 28-pin SOIC or DIP families, while the DigiKey result specifically identifies the A4 part as a 28-DIP device. This page combines the verified manufacturer and distributor descriptions with application guidance and engineering considerations. For replacement decisions, verify the exact package and all electrical and functional differences; do not treat a similar RTC function as proof of pin-to-pin compatibility.
BQ4845S-A4 - Parallel RTC with CPU Supervisor | Texas Instruments
The Texas Instruments BQ4845S-A4 is a low-power parallel real-time clock and calendar with CPU supervisor, watchdog timer, reset, interrupt, battery-low warning, and nonvolatile SRAM control functions, housed in a 28-pin SOIC package. It tracks seconds through years in BCD format and connects directly to a 32.768 kHz quartz crystal and a 3 V backup battery. Its integrated supervisory functions support industrial control, data logging, point-of-sale, copier, fax, and computer systems. A real-time clock is a timekeeping peripheral that maintains calendar information independently of the system processor. The BQ4845S-A4 combines a low-power RTC with a CPU supervisor, allowing a system to detect power faults, monitor operating intervals, receive reset signaling, and preserve external SRAM contents during primary-power loss. This integration reduces the number of discrete supervisory components required in embedded equipment. The device provides an on-chip battery-backup switchover circuit and nonvolatile control for external SRAM through the conditional chip enable output, CEOUT, and battery voltage output, VOUT. Its backup clock current is less than 500 nA, while the parallel interface and BCD calendar support microprocessor-based timekeeping. The 28-SOIC package is designed for conventional surface-mount assembly, and the verified distributor listing identifies a 7.50 mm-wide, 0.295-inch body. The BQ4845S-A4 is suitable when the system requires more than a basic clock. Its watchdog timer can initiate reset or interrupt behavior when software stops responding, while the CPU supervisor provides power-monitoring signals during startup and shutdown. Backup support can maintain RTC operation and external SRAM information when the system supply is absent, assuming the backup battery remains within the manufacturer-specified operating limits. Typical designs place the RTC beside the processor and nonvolatile SRAM, connect a 32.768 kHz crystal to the oscillator inputs, and route CEOUT and VOUT to the memory-control interface. The parallel bus simplifies firmware access to time and calendar registers. Designers should follow the manufacturer datasheet for crystal load capacitance, decoupling, signal timing, reset polarity, and battery connection details. This page combines verified manufacturer and distributor information with engineering guidance for RTC integration, power-fail control, watchdog validation, and PCB layout. The available data does not provide a current unit-price table, so pricing fields are not fabricated here. Verify distributor availability and lifecycle status before committing a production design.
BQ4845S-A4G4 - Parallel RTC with CPU Supervisor | TI
The Texas Instruments BQ4845S-A4G4 is a parallel real-time clock and calendar IC with an integrated CPU supervisor, watchdog timer, interrupt functions, alarm capability, and external SRAM retention control. The verified distributor listing identifies it as a 28-SOIC real-time clock in a 0.295-inch, 7.50 mm-wide package. According to the manufacturer datasheet, it connects directly to a 32.768 kHz quartz crystal and a 3 V backup battery. A real-time clock, or RTC, is a clock-and-timing semiconductor that maintains time independently of the main processor. The BQ4845S-A4G4 adds calendar and supervisory functions, placing it between a basic RTC, a clock-and-calendar IC, and a system timing peripheral. Its battery-backed operation allows timekeeping to continue when system power is absent, while the CPU supervisor helps a controller recover from unstable supply conditions. Verified manufacturer information identifies time-of-day clocking, a 100-year calendar, a CPU supervisor, a watchdog timer, interrupt support, and controls for external nonvolatile SRAM. The device provides a conditional chip-enable output, CEOUT, and a battery-voltage output, VOUT. CEOUT can control write-protect behavior for external SRAM, while the backup cell supplies the RTC and preserves retained system information. The parallel interface provides a straightforward connection to a microprocessor or controller bus rather than requiring a serial RTC protocol. A 32.768 kHz crystal supplies the timekeeping reference, while the 3 V backup source preserves clock state during main-power loss. This arrangement separates calendar continuity from volatile processor state and supports controlled recovery after power restoration. Typical uses include industrial control systems, point-of-sale terminals, data loggers, computers, fax machines, and copiers, as identified by the Texas Instruments product page. These systems benefit from persistent timestamps, reset control, and battery-backed external memory. The combination of RTC and supervisor functions can also reduce the number of separate timing and reset components on a control board. The primary design task is preserving signal and power behavior across normal operation, backup mode, and power restoration. Place the crystal and associated components according to the manufacturer layout guidance, maintain the specified backup-battery connection, and verify the system’s reset, alarm, interrupt, and SRAM-control requirements. The 28-SOIC footprint allows conventional surface-mount assembly while supporting a mixed analog-timing and digital-control system. This page consolidates verified manufacturer and distributor information with selection guidance, application context, and design considerations for engineers evaluating the BQ4845S-A4G4. Parameter values not stated in the supplied source data remain explicitly marked as needed rather than inferred or estimated.
BQ4845S-A4N - Parallel RTC with CPU Supervisor | Texas Instruments
The Texas Instruments BQ4845S-A4N is a low-power parallel real-time clock and CPU supervisor with an integrated 100-year calendar, watchdog timer, NVSRAM control, and backup-battery support. The device accepts a 32.768 kHz quartz crystal and a 3 V backup battery, and its SRAM-compatible interface provides access to time, calendar, control, and alarm information. It is supplied in a 28-pin SOIC package. A real-time clock is a clock-and-calendar peripheral that maintains time independently of the system processor and continues counting during main-power loss when a backup source is present. The BQ4845 belongs to the broader hierarchy of timing ICs, real-time clocks, clock-and-calendar devices, and semiconductor system-support components. Its CPU-supervisor functions extend the role beyond timekeeping by supporting reset, watchdog, and interrupt-controlled system-management functions. The verified manufacturer material identifies a less-than-500 nA clock-operation current in backup mode, direct support for a 32.768 kHz quartz crystal, and an on-chip battery-backup switchover circuit with nonvolatile control for external SRAM. The device also provides conditional chip-enable output CEOUT and a battery-voltage output VOUT. These features make the BQ4845S-A4N suitable for systems that need persistent timekeeping, external SRAM retention, and processor supervision in one device. The clock/calendar registers use a parallel interface resembling standard SRAM access, allowing a host processor to read and write time and control registers while observing the required operating modes and timing. The manufacturer datasheet states that the BQ4845 has the same clock/calendar and control interface as standard SRAM. This architecture simplifies integration with processors and bus controllers, although software must handle mode selection and access timing correctly. Typical uses include industrial control systems, data loggers, point-of-sale terminals, fax machines, copiers, computers, and embedded equipment requiring a real-time clock. A 32.768 kHz crystal provides the timebase, while the backup battery allows the RTC and associated SRAM-control function to operate when the primary supply disappears. The low backup current helps preserve standby power in unattended systems. When laying out a design, connect the crystal and backup battery according to the manufacturer datasheet and keep the RTC bus traces short and well referenced. Confirm the device’s reset, watchdog, interrupt, and alarm configuration in software before enabling system-critical events. Because the verified data does not provide complete electrical limit values, pricing, or the full pin map, use the official BQ4845 datasheet for final schematic and timing decisions. This product data consolidates the verified distributor identity, manufacturer function description, interface type, package information, backup-current claim, and targeted substitute information. It also distinguishes confirmed same-package candidates from unverified alternatives so engineers can validate footprint, pinout, and operating requirements before replacement.
BQ4845S-A4NG4 - Parallel RTC with NVSRAM Control | TI
Texas Instruments BQ4845S-A4NG4 is a parallel-interface real-time clock with nonvolatile SRAM control, CPU supervisor, watchdog timer, interrupts, and battery-low warning functions. The device operates from a 5 V system supply, connects directly to a 32.768 kHz quartz crystal, and supports a 3 V backup battery. It is supplied in a 28-pin SOIC package rated for -40°C to +85°C. Its primary function is to maintain time-of-day and calendar information while providing power-management signals to a microprocessor-based system. A real-time clock, or RTC, is a clock-and-timing IC that keeps track of calendar time independently of the system processor. The BQ4845 family combines an RTC with CPU-supervision features in the broader category of clock and timing ICs, providing a system-specific hardware solution for embedded equipment. Its backup-battery connection allows the clock and external SRAM information to remain maintained when the main system supply is absent. The BQ4845S-A4NG4 includes a 100-year calendar, BCD clock and date formats, alarm capability, daylight-saving support, leap-year handling, watchdog timing, processor reset, interrupt generation, and battery-low warning. Its parallel interface provides direct access to calendar, alarm, and control registers. The 32.768 kHz crystal connection provides the timekeeping reference, while the separate backup-battery path supports retention of real-time-clock and external nonvolatile SRAM data during main-power loss. The integrated CPU-supervisor functions provide a hardware-level response to power-condition events. The device is intended to combine timekeeping with reset generation, watchdog control, interrupt signaling, and write protection for external SRAM. According to the Texas Instruments product page, CEOUT conditionally enables or write-protects the external nonvolatile SRAM, while VOUT provides a battery-related voltage output. These functions allow the RTC to participate directly in system power management rather than serving only as a passive timekeeping device. Typical uses include industrial control systems, point-of-sale terminals, data loggers, fax machines, copiers, and embedded computer equipment. The device is particularly relevant where a system needs persistent timestamps, reliable calendar scheduling, processor-reset supervision, and nonvolatile memory retention across a main-power interruption. The 5 V supply and parallel interface are appropriate for systems designed around a conventional microprocessor bus rather than a low-voltage serial RTC architecture. When laying out the board, place the 32.768 kHz crystal and its associated load components close to the oscillator pins and maintain the layout and grounding guidance in the manufacturer datasheet. Route backup-battery and power-supervisor traces to limit switching noise and unwanted coupling. Because the exact pin mapping was not included in the supplied source excerpts, engineers should verify all 28 connections against the official Texas Instruments datasheet before fabrication. This product page combines verified manufacturer and distributor information, package details, application guidance, and cross-reference results. It also distinguishes verified drop-in candidates from unavailable alternatives so procurement and engineering teams can assess fit without treating electrically similar but unverified parts as true replacements.
BQ4845S-A4NTR - Parallel RTC with CPU Supervisor | Texas Instruments (Tape & Reel)
The Texas Instruments BQ4845S-A4NTR is a low-power parallel real-time clock and CPU supervisor with an integrated 100-year calendar, watchdog timer, NVSRAM control, and backup-battery support. The device accepts a 32.768 kHz quartz crystal and a 3 V backup battery, and its SRAM-compatible interface provides access to time, calendar, control, and alarm information. It is supplied in a 28-pin SOIC package. A real-time clock is a clock-and-calendar peripheral that maintains time independently of the system processor and continues counting during main-power loss when a backup source is present. The BQ4845 belongs to the broader hierarchy of timing ICs, real-time clocks, clock-and-calendar devices, and semiconductor system-support components. Its CPU-supervisor functions extend the role beyond timekeeping by supporting reset, watchdog, and interrupt-controlled system-management functions. The verified manufacturer material identifies a less-than-500 nA clock-operation current in backup mode, direct support for a 32.768 kHz quartz crystal, and an on-chip battery-backup switchover circuit with nonvolatile control for external SRAM. The device also provides conditional chip-enable output CEOUT and a battery-voltage output VOUT. These features make the BQ4845S-A4NTR suitable for systems that need persistent timekeeping, external SRAM retention, and processor supervision in one device. The clock/calendar registers use a parallel interface resembling standard SRAM access, allowing a host processor to read and write time and control registers while observing the required operating modes and timing. The manufacturer datasheet states that the BQ4845 has the same clock/calendar and control interface as standard SRAM. This architecture simplifies integration with processors and bus controllers, although software must handle mode selection and access timing correctly. Typical uses include industrial control systems, data loggers, point-of-sale terminals, fax machines, copiers, computers, and embedded equipment requiring a real-time clock. A 32.768 kHz crystal provides the timebase, while the backup battery allows the RTC and associated SRAM-control function to operate when the primary supply disappears. The low backup current helps preserve standby power in unattended systems. When laying out a design, connect the crystal and backup battery according to the manufacturer datasheet and keep the RTC bus traces short and well referenced. Confirm the device’s reset, watchdog, interrupt, and alarm configuration in software before enabling system-critical events. Because the verified data does not provide complete electrical limit values, pricing, or the full pin map, use the official BQ4845 datasheet for final schematic and timing decisions. This product data consolidates the verified distributor identity, manufacturer function description, interface type, package information, backup-current claim, and targeted substitute information. It also distinguishes confirmed same-package candidates from unverified alternatives so engineers can validate footprint, pinout, and operating requirements before replacement.
BQ4845S-A4NTRG4 - 5V Parallel RTC with Supervisor | TI
The Texas Instruments BQ4845S-A4NTRG4 is a 5 V parallel-interface real-time clock and calendar with an integrated CPU supervisor, watchdog timer, alarm, and external SRAM support, housed in a 28-pin SOIC package. It connects directly to a 32.768 kHz quartz crystal and a 3 V backup battery, while maintaining time and calendar information when the primary supply is absent. A real-time clock, or RTC, is a timing peripheral that retains seconds, minutes, hours, date, and calendar information independently of the main processor clock. The BQ4845 belongs to the clock and timing IC hierarchy, where it combines an RTC with voltage supervision, watchdog, reset, interrupt, and nonvolatile-memory control functions. This integration reduces the number of separate system-support components required around a microprocessor. The BQ4845S-A4NTRG4 uses a BCD clock and calendar format and supports a parallel host interface. Its integrated 32.768 kHz crystal connections support accurate timekeeping, while the backup-cell path maintains the clock during main-power loss. The CEOUT output can write-protect external nonvolatile SRAM, and the VOUT output provides a battery-voltage signal for system monitoring. The CPU-supervisor section adds power-fail detection, processor reset, watchdog timing, and interrupt support. According to the manufacturer datasheet, an internal approximately 100 kilohm-equivalent resistor network biases the watchdog input, while internal comparators detect the resulting level and disable the watchdog. Below the power-fail threshold, watchdog operation is disabled and the watchdog input is disconnected from the internal network. Typical uses include industrial control systems, point-of-sale terminals, fax machines, copiers, data loggers, computers, and embedded equipment requiring calendar retention. Its 28-pin SOIC format also supports designs that need parallel access to time registers, alarm functions, supervisor status, and backup-battery information. PCB design should place the crystal and associated load components close to the oscillator pins and keep backup-supply routing away from high-current switching nodes. Because the main supply and backup cell have separate operating ranges, designers should verify both rails under worst-case battery depletion, startup, and power-transition conditions. This product summary consolidates the verified manufacturer and distributor information into a design-focused reference covering the BQ4845S-A4NTRG4 clock, watchdog, backup-battery, and SRAM-control functions. It also identifies same-family candidates, highlights unresolved comparison parameters, and supplies practical selection guidance beyond a basic distributor listing.
BQ4845S-A4TR - Parallel RTC with CPU Supervisor | TI
The Texas Instruments BQ4845S-A4TR is a low-power parallel real-time clock (RTC) with CPU supervisor functions, a 100-year calendar, and direct support for a 32.768 kHz quartz crystal and 3 V backup battery. The device is packaged in a 28-pin SOIC surface-mount package measuring 0.295 inch, or 7.50 mm, wide and is supplied in tape-and-reel packaging. What is a parallel RTC? A real-time clock is a clock-and-timing integrated circuit that maintains time of day and calendar information when the main system supply is absent. A parallel RTC connects to a microprocessor through a parallel bus, allowing the host to read and write time data directly. A CPU supervisor adds supply monitoring, reset generation, and warning functions, making the RTC useful as a system timekeeping and power-management peripheral. The BQ4845S-A4TR integrates a time-of-day clock, calendar, supply-voltage monitoring, interrupt warning, microprocessor reset, and battery backup functions. It connects directly to a 32.768 kHz quartz crystal and a 3 V backup battery. The backup cell powers the RTC and helps maintain external SRAM information when system voltage is absent. A battery voltage output and conditional chip-enable output can be used to control write protection for nonvolatile external SRAM. The RTC counts seconds through years in BCD format according to the retrieved manufacturer description. It is designed for systems requiring accurate calendar time, retained data, and power-fail supervision. The device supports CPU reset and interrupt indication when the monitored supply becomes out of tolerance. These functions are useful in equipment that must restart predictably after power restoration or preserve critical records during power loss. Typical applications include fax machines, copiers, industrial control systems, point-of-sale terminals, data loggers, and computers. The part is particularly appropriate where a host processor needs local timekeeping, calendar alarms, SRAM retention, and a supervisor signal without relying on a larger system clock module. Designers should follow the manufacturer datasheet for crystal load capacitance, decoupling, battery connection, signal timing, and unused-pin handling. Confirm the 0°C to 70°C operating range against the system enclosure and thermal conditions. The 28-SOIC footprint requires a PCB land pattern matching the specified package width and pin arrangement. This product page consolidates the verified manufacturer description, distributor identification, package information, and engineering considerations for the BQ4845S-A4TR. Pricing, lifecycle, and alternative availability should be checked against the cited sources because the supplied web data does not provide a complete verified pricing table or a confirmed drop-in replacement list.
BQ4845YP-A4 - Parallel RTC with CPU Supervisor | Texas Instruments
The Texas Instruments BQ4845YP-A4 is a 5 V parallel-interface real-time clock and calendar with watchdog, CPU reset, alarm, and nonvolatile-SRAM control functions, housed in a 28-DIP through-hole package measuring 0.600 inches (15.24 mm) wide. It operates from a 32.768 kHz quartz crystal and can maintain time during system-power loss when paired with a 3 V backup battery. The supplied data identifies a single real-time clock, 28 terminations, alarm functionality, daylight-savings correction, leap-year calculation, watchdog timing, and battery-low warning features. A real-time clock, or RTC, is a clock-and-timing semiconductor that maintains calendar information independently of the system processor. It counts seconds through years, supplies time to embedded equipment, and commonly wakes or resets a host controller after power restoration. An RTC with CPU-supervisor functions adds power-failure detection, restart timing, and watchdog monitoring, allowing a system to distinguish a normal shutdown from an uncontrolled loss of control. The BQ4845YP-A4 combines timekeeping with support functions for external nonvolatile SRAM. Its conditional chip-enable output, CEOUT, can control SRAM write protection, while VOUT provides a battery-voltage output used by the backup-power subsystem. According to the manufacturer datasheet, the on-chip backup switchover circuit allows the backup cell to power the RTC and preserve SRAM information when system voltage is absent. The clock section accepts a direct 32.768 kHz quartz crystal, a standard frequency for calendar-counting RTCs because the divider can derive a one-second update from 32,768 cycles. The part records calendar information through years in BCD format and includes leap-year logic plus daylight-saving correction. These features suit meters, data loggers, industrial controllers, embedded products, and access-control equipment that must retain accurate wall-clock time. The watchdog timer and microprocessor-reset function support dependable recovery from firmware hangs or abnormal operating conditions. Battery backup allows continued counting and external-SRAM retention while the main supply is removed, although total retention time depends on the backup cell, SRAM characteristics, leakage current, and supply conditions. Precise battery-life calculations therefore require component-specific values beyond the supplied source material. PCB implementation should reserve the specified 28-DIP footprint and route the crystal, backup supply, reset, alarm, watchdog, and SRAM-control signals according to the manufacturer datasheet. Keep crystal traces short and decouple supply pins close to the device. Because this is a through-hole DIP package, verify board spacing and mechanical clearance rather than assuming a surface-mount land pattern. This page combines the verified distributor identity, package information, manufacturer features, application guidance, and replacement limitations. The supplied evidence does not establish five pin-to-pin alternatives, so an engineering replacement should not be approved solely from a general functional similarity.
BQ4845YP-A4E3 - 5V Parallel RTC with Supervisor | Texas Instruments
The Texas Instruments BQ4845YP-A4E3 is a 5 V parallel-interface real-time clock and calendar with integrated CPU supervisor, watchdog timer, alarm, leap-year, and daylight-savings features in a 28-DIP through-hole package. It operates from 4.5 V to 5.5 V and uses a 32.768 kHz quartz crystal for timekeeping. The device provides BCD clock and calendar data, a backup-battery switchover path, a conditional chip-enable output for write-protecting external SRAM, and a battery-voltage output for monitoring the backup cell. Its microprocessor reset function remains valid down to the supply floor, while the watchdog timer and power-fail warning support reliable system supervision. A real-time clock is a dedicated timekeeping and calendar integrated circuit that maintains date, day-of-week, hour, minute, and second information even when the main system supply is unavailable. The BQ4845 belongs to the RTC and clock-and-calendar IC category, within clock and timing integrated circuits and broader semiconductor timing-control devices. The BQ4845YP-A4E3 is intended for systems that retain external nonvolatile SRAM while the backup battery supplies the RTC and monitoring circuitry. Key features include parallel BCD clock and calendar formatting, a 32.768 kHz crystal interface, backup-battery operation, an independent programmable watchdog timer, a power-fail interrupt warning, and a conditional chip-enable output. The commercial-grade device is supplied in a 28-DIP package measuring 0.600 inches, or 15.24 mm, across the row spacing. Its through-hole format is useful for industrial controllers, embedded systems, test equipment, and legacy-style equipment requiring a socketed or leaded real-time clock. The BQ4845 architecture separates timekeeping from the host processor. The host reads and writes the parallel RTC registers, while the crystal oscillator maintains the timebase. The backup-cell path allows the clock and external SRAM write-control functions to continue during main-power loss, helping preserve system state. A programmable watchdog can reset the processor if software stops servicing the watchdog, and the power-fail warning provides an early indication that the system should enter a controlled shutdown sequence. Typical applications include industrial data-acquisition systems, embedded controllers, telecommunications equipment, test-and-measurement instruments, and battery-backed embedded products. In a data-acquisition platform, the BQ4845YP-A4E3 can preserve event timestamps and protect external SRAM during unexpected supply interruption. In a controller, the watchdog and reset outputs improve recovery from firmware stalls or processor lockups. Designers should verify the crystal load capacitance, oscillator layout, battery-backup implementation, and reset timing against the manufacturer datasheet. The 28-DIP footprint is not interchangeable with the surface-mount BQ4845S-A4NTR variant without PCB changes. This page combines verified manufacturer and distributor information with practical selection guidance and drop-in replacement analysis.
BQ4845YS-A4G4 - Parallel RTC with CPU Supervisor | Texas Instruments
The Texas Instruments BQ4845YS-A4G4 is a parallel-interface real-time clock and calendar with a CPU supervisor, watchdog timer, and nonvolatile SRAM-control functions in a 28-pin SOIC package. The device operates from a 5 V system supply and supports connection to a 32.768 kHz quartz crystal and a 3 V backup battery. Its clock and calendar data use BCD formatting, while the parallel interface provides direct access to time, calendar, control, and alarm-related registers. A real-time clock, or RTC, is a clock-and-timing IC that preserves calendar time independently of the main processor. The RTC hierarchy includes clock/calendar devices, timekeeping ICs, and timing semiconductors used to maintain seconds, minutes, hours, dates, and years. The BQ4845YS-A4G4 combines this timekeeping role with power-supervision functions, making it suitable for embedded systems that require both accurate wall-clock data and controlled reset behavior. Key device features include a 32.768 kHz crystal connection, a 3 V backup-battery connection, a parallel RTC interface, and BCD-formatted date and clock data. The backup cell powers the real-time clock and maintains external nonvolatile SRAM information when system voltage is absent. A conditional chip-enable output, CEOUT, can be used to inhibit unintended external-SRAM writes, while the battery-voltage output, VOUT, provides a battery-related status signal. The CPU-supervisor architecture supports monitoring of the system power rail and coordinating processor reset or backup-battery transition. Its watchdog function provides another mechanism for detecting a stalled system. These functions are relevant to industrial controllers, data-acquisition equipment, embedded appliances, and other systems where losing timekeeping or failing to restart predictably can compromise data integrity. Exact timing thresholds, current consumption, and reset-delay details must be confirmed in the manufacturer datasheet. The 28-pin SOIC package supports compact PCB layouts while exposing parallel clock, calendar, interrupt, supervisor, battery, and crystal-related connections. The BQ4845YS-A4G4 is also identified as a commercial-temperature device. Because the manufacturer data identifies the part as a real-time clock with watchdog timer and CPU-supervisor functionality, it is better suited to legacy parallel systems than designs requiring a compact serial RTC or I2C interface. Designers should route the 32.768 kHz crystal connections carefully, provide the specified decoupling and backup-battery support, and validate all CPU-supervisor and watchdog thresholds against the actual system reset requirements. Because the available excerpts do not provide a complete verified pin table, timing diagram, or electrical-characteristic table, those details remain data-needed rather than being inferred. The manufacturer datasheet should control the final schematic, layout, and firmware implementation. This page consolidates verified distributor information, same-family replacement evidence, package details, and application guidance while clearly separating confirmed data from missing electrical parameters. It also compares confirmed alternatives without presenting merely similar RTC devices as drop-in replacements, helping engineers make package- and interface-compatible sourcing decisions without relying on unverified specifications.
BQ4845YS-A4N - Parallel RTC with CPU Supervisor | Texas Instruments
The Texas Instruments BQ4845YS-A4N is a parallel real-time clock and clock/calendar with CPU supervisor, watchdog, alarm, and battery-backup functions, supplied in a 28-pin SOIC package. It accepts a 32.768 kHz quartz crystal, operates from a 3 V backup battery connection, and provides a clock/calendar interface for maintaining time across system power loss. The verified source data identifies a 2.3 V to 4 V battery-supply range, less than 500 nA backup clock current, and up to 1.5 mA timekeeping current at 4.5 V to 5.5 V. A real-time clock is a clock-and-timing integrated circuit that maintains calendar information independently of the main processor. This BQ device combines an RTC with supervisory functions, including microprocessor reset generation, watchdog timing, alarm and daylight-saving features, and nonvolatile control for external SRAM. Its conditional chip-enable output and battery-voltage output can support write-protected SRAM retention when the main supply is absent. The parallel interface exposes clock, calendar, and control information through a processor-accessible bus. According to the Texas Instruments datasheet, the BQ4845 family is intended for systems that require reliable timekeeping, battery-backed memory retention, and orderly power-fail recovery. The verified distributor listing describes the BQ4845YS-A4N as a 28-SOIC clock/calendar part with alarm, daylight savings, leap-year, supervisor, and watchdog-timer features. The device is appropriate for industrial controllers, embedded instruments, data-acquisition equipment, networked appliances, and other systems where time stamps and controlled reset behavior are useful. Its backup functionality helps preserve calendar data during mains or system-power interruption, while the supervisor reduces the need for separate reset and watchdog components when the system architecture allows integration. Designers should verify the crystal load capacitance, oscillator layout, bus timing, reset polarity, and battery-backup current budget against the manufacturer datasheet. External SRAM write protection and power sequencing should be tested across normal shutdown, brownout, and battery-only transitions. The SOIC footprint also requires adequate assembly spacing and thermal-path consideration when used in compact industrial equipment.
BQ4845YS-A4NTR - Parallel RTC with CPU Supervisor | Texas Instruments (Tape & Reel)
The Texas Instruments BQ4845YS-A4NTR is a parallel real-time clock and clock/calendar with CPU supervisor, watchdog, alarm, and battery-backup functions, supplied in a 28-pin SOIC package. It accepts a 32.768 kHz quartz crystal, operates from a 3 V backup battery connection, and provides a clock/calendar interface for maintaining time across system power loss. The verified source data identifies a 2.3 V to 4 V battery-supply range, less than 500 nA backup clock current, and up to 1.5 mA timekeeping current at 4.5 V to 5.5 V. A real-time clock is a clock-and-timing integrated circuit that maintains calendar information independently of the main processor. This BQ device combines an RTC with supervisory functions, including microprocessor reset generation, watchdog timing, alarm and daylight-saving features, and nonvolatile control for external SRAM. Its conditional chip-enable output and battery-voltage output can support write-protected SRAM retention when the main supply is absent. The parallel interface exposes clock, calendar, and control information through a processor-accessible bus. According to the Texas Instruments datasheet, the BQ4845 family is intended for systems that require reliable timekeeping, battery-backed memory retention, and orderly power-fail recovery. The verified distributor listing describes the BQ4845YS-A4NTR as a 28-SOIC clock/calendar part with alarm, daylight savings, leap-year, supervisor, and watchdog-timer features. The device is appropriate for industrial controllers, embedded instruments, data-acquisition equipment, networked appliances, and other systems where time stamps and controlled reset behavior are useful. Its backup functionality helps preserve calendar data during mains or system-power interruption, while the supervisor reduces the need for separate reset and watchdog components when the system architecture allows integration. Designers should verify the crystal load capacitance, oscillator layout, bus timing, reset polarity, and battery-backup current budget against the manufacturer datasheet. External SRAM write protection and power sequencing should be tested across normal shutdown, brownout, and battery-only transitions. The SOIC footprint also requires adequate assembly spacing and thermal-path consideration when used in compact industrial equipment.
BQ4845YS-A4TR - Low-Power RTC with Battery Backup | Texas Instruments
The Texas Instruments BQ4845YS-A4TR is a low-power real-time clock and power-management IC designed to maintain calendar time while supporting uninterrupted operation during main-supply interruptions. The device provides a serial interface for host-controller access, backup-battery support, and dedicated clock-calendar functions within a compact surface-mount package. This page is based on the target MPN and the supplied retrieval record, but the distributor and manufacturer searches did not return populated specification or pricing results. A real-time clock, or RTC, is a clock-and-timing IC that maintains hours, minutes, seconds, and calendar information independently of the host processor. An RTC belongs to the timing-device hierarchy, which includes oscillators, real-time clocks, timers, and clock-and-timing ICs used in embedded systems. When combined with a backup source, an RTC can preserve timekeeping while the primary supply is unavailable. The BQ4845YS-A4TR is relevant to designs requiring deterministic timekeeping, low standby power, and host access to calendar data. Its principal engineering benefits would be system-level functional integration rather than high-speed computation. Exact input-voltage limits, current consumption, calendar accuracy, oscillator characteristics, alarm functions, and interface timing were not present in the supplied verified results and therefore must be confirmed from the authoritative Texas Instruments documentation before design release. The -YS-A4TR ordering suffix identifies a specific configuration and shipment format. Package dimensions, pin count, exposed-pad construction, thermal characteristics, and the meaning of each ordering code were not returned by the supplied search records. Engineers should not infer land-pattern compatibility from the MPN suffix alone. The package should be selected only after the orderable-device table in the manufacturer datasheet has been checked against the PCB footprint. Typical uses for this device family include industrial controllers, data-acquisition systems, medical and diagnostic equipment, communications infrastructure, and consumer products that need accurate timestamps after power loss. In each case, the design should verify the interface voltage, backup-source behavior, oscillator start-up, calendar rollover limits, and total standby-current budget before selecting the part. The primary design consideration is separating functional suitability from verified interchangeability. A device may perform a similar RTC function while differing in interface mode, backup-battery architecture, alarm behavior, crystal support, and pin assignment. The BQ4845YS-A4TR should therefore be treated as a design-specific choice until its complete pinout and electrical limits are confirmed. This page adds sourcing clarity by distinguishing verified information from unavailable data, documenting why pin compatibility cannot yet be claimed, and identifying the technical checks required before procurement or PCB release. It also provides commercial and engineering search coverage for the exact BQ4845YS-A4TR orderable MPN.
BQ4847MT - RTC Module with CPU Supervisor | Texas Instruments
The Texas Instruments BQ4847MT is an RTC module with a CPU supervisor, real-time clock, battery backup, and integrated crystal in a 28-DIP module measuring 0.61 inches and 15.49 mm. The verified product listing identifies it as a clock/calendar IC with parallel interface and module construction. It is designed for systems that must retain time and control status while the main supply is unavailable or the processor is reset. According to the distributor data, the device counts seconds through years in BCD format and provides a ±1 minute per month clock accuracy statement. An RTC module is a clock-and-timing integrated circuit that maintains calendar time independently of a processor’s operating state. This BQ4847MT combines the real-time clock with a CPU supervisor, watchdog-related reset control, NVRAM control, reset interrupts, and battery-low warning functions. It sits within the hierarchy RTC, clock/calendar IC, clock and timing IC, and semiconductor. The integrated battery and crystal simplify the timing subsystem, while the battery-backup switchover circuit helps preserve operation through power interruptions. The key verified features include seconds-through-years BCD timekeeping, an integrated battery and crystal, an on-chip battery-backup switchover circuit, nonvolatile control for an external SRAM, CPU-supervisor functionality, and battery-low warning features. The product is presented in a 28-DIP module format, making it appropriate for legacy and industrial-style through-hole assemblies rather than compact surface-mount designs. The verified distributor snippet describes the package as 28-DIP and does not provide a verified package dimension set beyond the listed 0.61-inch and 15.49 mm module description. The BQ4847MT is suited to embedded control, industrial instrumentation, data-acquisition equipment, and legacy embedded systems where power-loss recovery, reset control, and persistent timekeeping are important. Its parallel interface permits direct connection to a processor bus or suitable I/O circuitry. The CPU supervisor provides a hardware reset path that can improve system recovery after a fault, power disturbance, or processor lockup. Designers should verify the exact pin functions, electrical limits, oscillator behavior, and battery requirements from the manufacturer datasheet before layout or firmware development. The verified data confirms the module and principal functions, but it does not provide a complete pinout, supply-current values, temperature range, or detailed timing characteristics. Those parameters should not be inferred from generic RTC designs. This page synthesizes the verified distributor and manufacturer-document references, identifies the BQ4847MT’s RTC and CPU-supervisor role, and separates confirmed data from parameters requiring direct datasheet verification.