BQ4802YDWG4 - Parallel RTC with CPU Supervisor | Texas Instruments
MPN： BQ4802YDWG4 ✓ 啟用中BQ4802YDWG4 概覽
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.
直接替換替代品，適用於 BQ4802YDWG4 — 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： BQ4802YDWG4 （相同外形與佔位） — 差異在於 Product Type, Package, Package Width.
BQ4802YDW
✅ 直接替換聯絡詢價
查看資料表 →BQ4845YS-A4TR
✅ 直接替換聯絡詢價
查看資料表 →BQ4802YDWG4 規格
| Product Type | Y2K-compliant parallel real-time clock with CPU supervisor and external NVSRAM control |
| Manufacturer | Texas Instruments |
| Clock IC Type | RTC |
| 介面類型 | Parallel |
| Clock Format | BCD |
| 供應電壓 | 5 V Vcc |
| 封裝 | 28-SOIC |
| Package Width | 0.295 in (7.50 mm) |
| 安裝類型 | Surface mount |
| Calendar Support | Century-based Y2K-compliant calendar |
| Time-of-Day Support | Real-time clock with BCD time and calendar data |
| CPU Supervisor | Yes |
| External NVSRAM Control | Yes |
| Reported Distributor Inventory | 3,520 pieces |
| Reported Reference Unit Price | $7.8255 per piece |
| Reported Delivery Timing | March 8 to March 13; year not specified |
BQ4802YDWG4 0.295 in (7.50 mm) 腳位配置指南
BQ4802YDWG4（0.295 in (7.50 mm) 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： BQ4802YDWG4.
請參閱 資料表 以查看完整腳位配置。
典型應用
BQ4802YDWG4 適用於 6 應用s: Industrial Embedded Controllers, Data-Acquisition Equipment, Power-Failure-Aware Control Systems, Communications and Network Equipment, Battery-Backed Security and Access Systems, Automotive and Transportation Control Electronics.
Industrial Embedded Controllers
The BQ4802YDWG4 fits industrial embedded controllers that need calendar time independent of the host microcontroller and hardware supervision during supply disturbances. Its verified Y2K-compliant parallel RTC and CPU-supervisor functions combine timekeeping with power-failure awareness, while the 28-SOIC package supports compact surface-mount assembly. The design should use the manufacturer’s recommended backup-battery, reset, and decoupling arrangement, then validate reset timing and state-retention behavior across power cycles.
推薦
Data-Acquisition Equipment
The BQ4802YDWG4 is appropriate for measurement systems where timestamps must remain consistent when the main controller is reset or temporarily unavailable. Its BCD parallel interface makes the time registers convenient for processor-based logging, and the CPU supervisor provides a hardware monitoring path. External NVSRAM control can support retention of calibration or acquisition metadata. Because the verified data does not provide oscillator accuracy or supply-current limits, measurement timing and battery life must be calculated from the official datasheet.
推薦
Power-Failure-Aware Control Systems
The BQ4802YDWG4 can support systems that must detect supply degradation and place critical information into nonvolatile storage before power loss. The verified description confirms CPU-supervisor and external-NVSRAM-control functions, which help coordinate orderly shutdown or state preservation. Designers should examine the exact supervisor threshold, response delay, reset behavior, and NVSRAM write timing in the Texas Instruments datasheet; those values are not present in the supplied distributor snippets.
推薦
Communications and Network Equipment
The BQ4802YDWG4 can provide timekeeping and power monitoring in communications equipment where event logs and reboot diagnostics benefit from real calendar data. Its parallel interface allows integration with processor buses, and the external NVSRAM control can help preserve diagnostic information during unexpected supply loss. The verified data identifies a 5 V Vcc part and 28-SOIC package, but it does not establish protocol timing, isolation, or network-specific qualification; those requirements need separate verification.
推薦
Battery-Backed Security and Access Systems
The BQ4802YDWG4 can support access-control, alarm, and event-logging systems that need timestamps and controlled shutdown behavior. The century-based calendar helps record dates correctly, while the CPU supervisor and NVSRAM control provide hardware resources for preserving state if the primary rail fails. The verified data does not state backup-battery voltage, current consumption, or alarm timing, so battery selection and security-level compliance require separate manufacturer and standards documentation.
推薦
Automotive and Transportation Control Electronics
The BQ4802YDWG4 may be evaluated for transportation electronics where calendar logging and power-state monitoring are useful, subject to qualification review. Its verified package is 28-SOIC surface mount, and the integrated CPU supervisor can assist system reset management. However, the supplied data does not confirm AEC-Q100 qualification, automotive temperature range, vibration performance, or automotive supply criteria, so it should not be treated as an automotive-qualified part without an official declaration.
推薦
推薦產品摘要
工程參考資料，適用於 BQ4802YDWG4 — 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 | BQ4802YDW | BQ4845YS-A4TR |
|---|---|---|---|
| Brand | Texas Instruments | Texas Instruments | Texas Instruments |
| Package | 28-SOIC | 28-SOIC family context; exact package verification required | 28-SOIC |
| Clock Type | Real-time clock | BQ4802Y family RTC | Parallel real-time clock |
| Interface | Parallel | Parallel family context | Parallel |
主要差異化特點
- Integrated RTC and supervision (對比BQ4845YS-A4TR)
- Y2K-compliant calendar positioning (對比BQ4845YS-A4TR)
- BCD parallel interface (對比BQ4845YS-A4TR)
- Known distributor reference (對比BQ4845YS-A4TR)
設計說明
Use the manufacturer’s 28-SOIC land pattern and confirm pin 1 orientation before routing the parallel bus. Keep the RTC, supervisor, and NVSRAM-related traces away from noisy switching nodes and provide a clean return path for the digital ground. Because the verified material identifies the package but not the complete pinout, do not release a PCB footprint until the official mechanical drawing and pin table have been checked.
Design the 5 V supply and backup-power paths around the exact datasheet limits, including allowed voltage tolerance, current consumption, and power-fail behavior. The verified listing only states 5 V Vcc; it does not provide current or dropout data. Validate the backup capacitor, battery connection, and NVSRAM write-enable timing in a hardware simulation and in power-cycle testing rather than assuming that any voltage variation is tolerated.
Do not treat the G4, YDWG, or tape-and-reel suffix as automatically interchangeable without checking the orderable part number. Verify the exact temperature grade, package, reel orientation, and manufacturer status. Also avoid confusing the BQ4802Y with a generic serial RTC: the verified device is a parallel, BCD-format RTC with CPU-supervisor and external-NVSRAM-control functions, so register maps and bus timing are critical.
Route the parallel interface as a short, controlled digital bus and account for processor input capacitance, bus direction changes, and any required pull devices only after checking the datasheet. The verified data does not provide setup, hold, or access-time values, so those parameters must be obtained before selecting pull-ups, bus buffers, or processor speed. A logic analyzer should verify read cycles after power-up and after supervisor reset events.
合規資訊
The supplied verified results do not provide compliance declarations. RoHS, REACH, AEC-Q100, lead-free, halogen-free, and conflict-minerals status must be confirmed from the current Texas Instruments documentation.
