BQ4285P-SB2 - 114x8 NVSRAM RTC Clock/Calendar | TI
MPN： BQ4285P-SB2 ✓ 啟用中BQ4285P-SB2 概覽
A real-time clock is a clock-and-timing integrated circuit that maintains time and calendar information independently of the system’s main processor. It is useful when a system must preserve date, time, and configuration data across power loss. The BQ4285P-SB2 extends that role by integrating 114 bytes of NVRAM and NVRAM control, allowing the same device to provide both timekeeping and retained storage.
The BQ4285P-SB2 is listed by Texas Instruments and distributors as a parallel-interface RTC clock/calendar with 114 bytes of NVRAM. Its 24-DIP package is intended for through-hole PCB assembly and provides a direct package format for designs requiring a conventional DIP footprint. The verified material also describes compatibility-oriented use in IBM AT-compatible computers and functionally compatible calendar arrangements, although exact timing, voltage, and electrical limits must be taken from the manufacturer datasheet.
Typical applications include legacy computer clock/calendar replacement, industrial control systems requiring retained configuration data, data-acquisition equipment, instrumentation, embedded systems with battery-backed timekeeping, and products that need both RTC data and a small nonvolatile parameter store. The integrated NVRAM can simplify designs by reducing the number of separate retention components, provided the host software manages the device interface correctly.
The principal design consideration is interface compatibility. Because this is a 24-pin DIP through-hole device with a parallel clock/calendar and NVRAM organization, PCB layout, signal levels, supply requirements, and software register access must be verified before substitution. Do not assume that a similarly named RTC is interchangeable without comparing the manufacturer pinout and datasheet timing specifications. The verified data supports the 114 x 8 NVRAM organization and 24-DIP package, but does not provide every electrical timing parameter in the supplied records.
This product summary synthesizes the verified distributor descriptions, manufacturer-linked datasheet result, package information, and cross-reference findings. It distinguishes documented facts from parameters that require direct confirmation from the complete Texas Instruments datasheet, helping engineers identify the correct RTC before requesting samples or placing an order.
直接替換替代品，適用於 BQ4285P-SB2 — 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： BQ4285P-SB2 （相同外形與佔位） — 差異在於 Package.
DS14285+
✅ 直接替換📋 參考替代品（不在目錄中）
DS14285N
✅ 直接替換📋 參考替代品（不在目錄中）
BQ4285P-SB2 規格
| Product Type | Real-Time Clock (RTC) with NVRAM control |
| NVRAM Organization | 114 x 8 bits |
| Clock/Calendar Data | RTC clock/calendar |
| 介面 | Parallel |
| 封裝 | 24-DIP, 0.600 inch, 15.24 mm |
| 安裝類型 | Through-hole |
| 腳位數 | 24 pins |
| Manufacturer | Texas Instruments |
| Function Description | Real-Time Clock RTC with NVRAM control |
| Compatibility Reference | IBM AT-compatible computers and other applications |
| Calendar Compatibility | Day of week, day of month, month, year, and related calendar functions |
BQ4285P-SB2 24-dip, 0.600 inch, 15.24 mm 腳位配置指南
BQ4285P-SB2（24-dip, 0.600 inch, 15.24 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： BQ4285P-SB2.
請參閱 資料表 以查看完整腳位配置。
典型應用
BQ4285P-SB2 適用於 6 應用s: IBM AT-Compatible Clock/Calendar, Industrial Data Acquisition, Instrumentation and Test Equipment, Embedded Control with Retained Configuration, Legacy Peripheral and Bus Timing, Battery-Backed Product Controller.
IBM AT-Compatible Clock/Calendar
The BQ4285P-SB2 is a strong fit when an IBM AT-compatible system needs a parallel RTC and retained calendar data. Its documented clock/calendar function and compatibility-oriented design target legacy computer clock and calendar replacement, while the 114 x 8 NVRAM can hold configuration or status information alongside timekeeping. The 24-DIP through-hole package supports conventional PCB layouts, but designers should verify every signal, supply requirement, and software register against the manufacturer datasheet before production use.
推薦
Industrial Data Acquisition
The BQ4285P-SB2 can support industrial data-acquisition equipment that must record events with a real date and time and retain small configuration parameters during power loss. Its parallel RTC interface is appropriate for systems that already use a host bus or dedicated control logic, while the integrated 114 x 8 NVRAM provides a compact place for calibration or operating-status data. The design must account for through-hole assembly, signal integrity, backup-power behavior, and the exact electrical limits not supplied in the verified web excerpts.
推薦
Instrumentation and Test Equipment
Use the BQ4285P-SB2 in instrumentation that needs traceable event timestamps and retained setup information. The RTC supplies clock/calendar data, and the 114 x 8 NVRAM can store small operating parameters, calibration identifiers, or sequence numbers without relying only on volatile RAM. Because the device is a 24-DIP through-hole parallel-interface part, it is most practical in equipment where a legacy-style controller, backplane, or manually assembled prototype can provide compatible bus timing and pin connections.
推薦
Embedded Control with Retained Configuration
The BQ4285P-SB2 fits legacy embedded-control boards that need timekeeping plus nonvolatile configuration storage. Instead of separating the RTC from a small retention memory, the integrated 114 x 8 NVRAM can provide a shared device for time and limited persistent data. The implementation should use the manufacturer’s interface timing and verify backup supply behavior, NVRAM write limits, and reset-state assumptions. Its DIP format favors through-hole industrial or controller-board layouts rather than compact surface-mount designs.
推薦
Legacy Peripheral and Bus Timing
The parallel RTC interface and 24-DIP package make the BQ4285P-SB2 suitable for legacy peripheral boards that expose a broad bus to an RTC and calendar circuit. It can maintain time while the host is reset or unavailable and retain up to the documented 114 x 8 NVRAM organization for small persistent parameters. Board bring-up should include signal timing checks, bus contention testing, grounding review, and direct comparison with the datasheet pinout because the supplied web results do not provide individual pin functions.
推薦
Battery-Backed Product Controller
The BQ4285P-SB2 is potentially useful in battery-backed controller products that need date, time, and a small amount of retained data during power interruption. The RTC provides the timekeeping role and the integrated NVRAM provides persistent configuration storage, while the DIP package supports through-hole assembly in larger control boards. Before selecting it for a battery product, verify standby current, battery chemistry compatibility, oscillator accuracy, data-retention duration, and NVRAM endurance because those values are not present in the verified excerpts.
推薦
推薦產品摘要
工程參考資料，適用於 BQ4285P-SB2 — 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 | DS14285+ | DS14285N |
|---|---|---|---|
| Product Type | RTC with NVRAM control | RTC with consistent terminals and packages | RTC with consistent terminals and packages |
| Package | 24-DIP, 0.600 inch, 15.24 mm | 24-DIP | 24-DIP |
| Mounting Type | Through-hole | Through-hole | Through-hole |
| Clock/Calendar | RTC clock/calendar | Real-time clock calendar | Real-time clock calendar |
| Manufacturer | Texas Instruments | Maxim Integrated | Maxim Integrated |
主要差異化特點
- Integrated retained storage alongside the RTC (對比DS14285+)
- Direct legacy-computer positioning (對比DS14285N)
- Documented parallel interface and DIP integration (對比DS14285N)
設計說明
Treat the BQ4285P-SB2 as a through-hole 24-DIP component and preserve the verified 0.600 inch, 15.24 mm package format when laying out the PCB. Confirm the manufacturer pin numbering and pin names before routing the parallel bus; the supplied data identifies the package but does not provide the individual pin map. Keep the RTC and its associated traces away from high-current switching nodes and noisy clock sources to reduce errors in timekeeping and bus reads.
Verify the complete supply-voltage range, current consumption, and backup-power behavior from the Texas Instruments datasheet before connecting the RTC to system power or a backup battery. The verified records do not provide these values, so do not infer them from the 5 V or battery references associated with legacy RTC designs. Check power-up sequencing, ground continuity, and decoupling requirements at the device pins, then validate read and write behavior across cold-start and power-loss conditions.
The BQ4285P-SB2 uses a parallel clock/calendar interface, so host-bus timing and signal settling must be checked against the manufacturer timing specifications. Confirm address, data, enable, read/write, interrupt, and NVRAM-control behavior using the complete datasheet rather than distributor summaries. For longer traces or slower buses, use appropriate buffering and isolate noisy peripherals; the DIP package itself does not compensate for poor bus timing.
Do not substitute DS14285+ or DS14285N solely because the comparison pages show the same 24-DIP format. The verified cross-reference result states that terminals and packages are consistent, but it does not quantify supply voltage, NVRAM capacity, calendar registers, timing, or oscillator performance. Perform a pin-by-pin and register-by-register review, prototype the replacement, and confirm that IBM AT-compatible software behavior remains unchanged before approving it for production.
合規資訊
The supplied verified web results do not explicitly state RoHS, REACH, AEC-Q100, lead-free, halogen-free, or conflict-minerals status for BQ4285P-SB2.
