BQ4802YDW - 5V Parallel RTC with Supervisor | TI
MPN： BQ4802YDW ✓ 啟用中BQ4802YDW 概覽
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 BQ4802YDW 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 BQ4802YDW 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.
直接替換替代品，適用於 BQ4802YDW — 相同封裝，腳位對腳位相容。需重新設計 PCB 的不同封裝零件不列入。
此系列的變體
與下列產品可直接替換的同系列型號： BQ4802YDW （相同外形與佔位） — 差異在於 Package, Package Width, Product Type.
此產品無可直接替換的替代品。
申請替代品BQ4802YDW 規格
| Product Type | Real-time clock and calendar IC with CPU supervisor |
| Operating Voltage Variant | 5 V operation for bq4802Y |
| Timekeeping Format | BCD format |
| Calendar Capability | Counts seconds through centuries |
| Backup Mode Clock Operating Current | Less than 500 nA |
| Backup Function | On-chip battery-backup switchover circuit |
| Nonvolatile Control | Nonvolatile control for external SRAM |
| Supervisor Function | CPU supervisor |
| 介面 | Parallel |
| 封裝 | 28-pin SOIC |
| Package Width | 7.50 mm (0.295 in) |
| 安裝類型 | Surface mount |
BQ4802YDW 7.50 mm (0.295 in) 腳位配置指南
BQ4802YDW（7.50 mm (0.295 in) 封裝）的腳位配置。 腳位編號、功能與連接圖定義於製造商資料手冊中。請參閱該手冊以取得確切的封裝尺寸與焊接指引。
無詳細腳位定義資料： BQ4802YDW.
請參閱 資料表 以查看完整腳位配置。
典型應用
BQ4802YDW 適用於 6 應用s: Industrial Control Systems, Point-of-Sale Equipment, Fax Machines and Copiers, Embedded Data Loggers, Battery-Backed Industrial Equipment, Microprocessor Supervisory Systems.
Industrial Control Systems
BQ4802YDW fits industrial controllers that require independent calendar time and supervisory power monitoring. The bq4802Y provides 5 V operation, parallel communication, century-based counting in BCD, and an on-chip battery-backup switchover circuit, allowing a controller to retain time-of-day information when the main supply falls away. Its less-than-500-nA backup clock current is useful for systems that spend substantial time operating from a backup source. The CPU supervisor can support orderly processor reset during power transitions, although exact thresholds, reset delay, and temperature limits must be verified in the manufacturer datasheet before production release.
推薦
Point-of-Sale Equipment
BQ4802YDW is suitable for point-of-sale systems that need dependable transaction timestamps and controlled behavior during power interruptions. The century-based calendar and BCD timekeeping support date and time records, while the parallel interface connects the RTC to a processor bus. The battery-backup switchover helps preserve timekeeping when mains or system power is unavailable, and the sub-500-nA backup operating-current specification supports low standby drain. System integrators should still validate clock accuracy, supervisor thresholds, bus timing, and environmental requirements against the specific POS architecture.
推薦
Fax Machines and Copiers
BQ4802YDW can support the timekeeping and power-sequencing needs of office imaging equipment. The real-time clock and century-based calendar provide a persistent date and time reference for document logs, scheduled jobs, and service records. Its CPU supervisor function is useful when an embedded controller must recover predictably after power restoration, while the battery-backup switchover protects the timekeeping function during short supply interruptions. The verified family information identifies fax machines and copiers as intended applications, but mechanism timing, backup-cell life, and production environmental limits must be validated from the complete datasheet.
推薦
Embedded Data Loggers
BQ4802YDW is appropriate for embedded systems that must associate measurements or events with calendar time even when the host processor is reset or temporarily unpowered. The 5 V bq4802Y variant combines a parallel real-time clock, century-based calendar, and CPU supervisor in one 28-pin SOIC, reducing the number of discrete timing and reset-support devices. Backup mode clock current below 500 nA is favorable for low-power installations. Designers should define the backup-source topology, verify switchover behavior, and confirm that the RTC accuracy and environmental ratings satisfy the logger’s field requirements.
推薦
Battery-Backed Industrial Equipment
BQ4802YDW can serve battery-backed industrial equipment requiring a persistent real-time reference and supervisory reset function. The on-chip battery-backup switchover circuit, nonvolatile control for external SRAM, and less-than-500-nA backup clock current provide a foundation for systems that must retain timekeeping during main-power loss. The parallel interface allows connection to a microprocessor-controlled supervisory architecture. Because the verified material does not provide retention time, backup-cell requirements, or power-supply limits, the battery should be selected only after reviewing the manufacturer recommendations and testing worst-case battery and temperature conditions.
推薦
Microprocessor Supervisory Systems
BQ4802YDW is useful when an embedded system needs both timekeeping and CPU-supervision functions in a single peripheral. The RTC can maintain seconds, minutes, hours, and calendar information, while the supervisor supports power-state monitoring and reset control for the host processor. The 5 V bq4802Y version and 28-pin SOIC package fit systems designed around a parallel bus. Designers must confirm reset polarity, threshold voltage, response timing, and pin-level signal behavior from the datasheet, especially if the processor has unusual brownout or startup requirements.
推薦
推薦產品摘要
工程參考資料，適用於 BQ4802YDW — 比較、設計指引及合規資訊。
選型指南
與替代品比較
| 參數 | 本產品 |
|---|---|
| Package | 28-pin SOIC |
| Brand | Texas Instruments |
| Product Type | Parallel real-time clock and calendar IC with CPU supervisor |
| Operating Voltage | 5 V operation for bq4802Y |
| Timekeeping Format | BCD, counts seconds through centuries |
| Backup Clock Current | Less than 500 nA in backup mode |
| Backup Support | On-chip battery-backup switchover circuit |
| Nonvolatile Support | Nonvolatile control for external SRAM |
| Supervisor | CPU supervisor integrated |
| Applications | Fax machines, copiers, industrial control systems, point-of-sale equipment |
| Lifecycle Status | Active |
| Distributor Availability | DigiKey and Mouser listings |
主要差異化特點
- Integrated calendar timekeeping and CPU supervision (對比BQ4845YS-A4TR)
- 5 V application-specific variant (對比BQ4802LY)
- Backup-mode power focus (對比M48T58Y-70MH1F)
設計說明
Design the backup-cell and main-supply path around the manufacturer’s recommended switching topology. The verified BQ4802Y feature summary confirms an on-chip battery-backup switchover circuit and less than 500 nA clock operating current in backup mode. Do not treat the backup figure as the normal active current, and do not select the backup cell or series components without checking the datasheet’s voltage limits, leakage requirements, and transition behavior.
Place the BQ4802YDW close to the processor’s parallel bus and route the clock, data, and control traces with short paths and controlled return paths. Keep the backup-network area away from noisy switching nodes and follow the manufacturer’s recommended decoupling arrangement. The verified record confirms a 28-pin SOIC and 7.50 mm width, but it does not provide a land pattern, so the mechanical drawing must control pad and solder-mask design.
Do not confuse BQ4802YDW with the 3.3 V bq4802LY variant. The verified feature summary identifies bq4802Y as the 5 V version, and changing voltage variants can affect the complete system power budget. Also avoid assuming that any RTC with a 28-pin package is a drop-in replacement: pin names, supervisor polarity, calendar behavior, backup current, and interface timing must be compared before substitution.
合規資訊
The supplied manufacturer and distributor excerpts do not state RoHS, REACH, AEC-Q100, lead-free, halogen-free, or conflict-minerals status. Compliance values are therefore unknown rather than assumed.