BQ4850YMA-85 - 512Kx8 NVSRAM RTC | Texas Instruments
部品番号: BQ4850YMA-85 ✓ 生産中| 数量 | 単価 | 小計 |
|---|---|---|
| 1 | $0 | $0.00 |
| 10 | $0 | $0.00 |
| 100 | $0 | $0.00 |
| 500 | $0 | $0.00 |
| 1,000 | $0 | $0.00 |
BQ4850YMA-85 概要
A real-time clock module is a clock-and-timing IC that maintains calendar and time information independently of the host processor's main clock. This device provides RAM-like clock access, BCD time and calendar counting, and an interface intended to resemble an x8 SRAM. Its broader system position is timekeeping and data retention within embedded control, industrial instrumentation, and legacy computer equipment.
The key verified characteristics are 512Kx8 NVSRAM organization, a 4.5 V to 5.5 V operating supply, a parallel interface, and integrated SRAM, RTC, crystal, power-fail control, and battery functions. The supplied search data also identifies unlimited write capability as a feature, although the detailed write-cycle limit, retention duration, and electrical timing values are not provided.
The BQ4850YMA-85 uses BCD-formatted time information and a date format identified by the supplied search result as YY-MM-DD-dd, with time expressed as HH MM SS in 24-hour format. This organization can simplify firmware access, but the host software should still validate register maps, alarm behavior, and power-fail timing before production release.
Typical uses include industrial controllers, data-acquisition equipment, embedded instruments, and legacy systems requiring a parallel RTC with nonvolatile data storage. The 32-DIP package favors through-hole assembly or socketed prototyping rather than compact surface-mount consumer products.
Designers should verify the complete pinout and timing values from the manufacturer datasheet, preserve decoupling and battery backup behavior, and validate power-fail recovery before substitution. Because verified drop-in alternatives are scarce, functional alternatives must not be treated as pin-compatible without manufacturer confirmation.
This page consolidates verified distributor information, sourcing links, application context, and design cautions that are not all available from a single manufacturer datasheet listing. It also distinguishes verified data from parameters that still require engineering confirmation.
ドロップイン代替品: BQ4850YMA-85 — 同一パッケージでピン互換。PCBの作り直しが必要な異なるパッケージの部品は除外されています。
クイック比較ツール — 並列比較する代替部品を選択:
BQ4850YMA-85N
✅ ドロップイン📋 参考代替品（カタログ未掲載）
BQ4850YMA-85 仕様
| Product Type | RTC module with 512Kx8 NVSRAM |
| Supply Voltage Range | 4.5 V to 5.5 V |
| インターフェース | Parallel |
| Memory Organization | 512Kx8 |
| パッケージ | 32-DIP module |
| Package Width | 0.610 inch (15.49 mm) |
| 実装タイプ | Through-hole |
| Integrated Functions | SRAM, real-time clock, crystal, power-fail control circuit, and battery |
| Time Format | HH MM SS, 24-hour |
| Date Format | YY-MM-DD-dd |
| Calendar Encoding | BCD |
| Clock Access | RAM-like |
| Memory Compatibility | Pin-compatible with industry-standard x8 SRAMs |
| Write Capability | Unlimited writes |
| RTC Counting Range | Seconds through years |
| Power-Fail Control | Integrated |
| Battery Backup | Integrated |
BQ4850YMA-85 0.610 inch (15.49 mm) ピン配置ガイド
BQ4850YMA-85 (0.610 inch (15.49 mm) パッケージ) のピン配置。 ピン番号、機能、接続図はメーカーのデータシートで定義されています。正確なフットプリントとはんだ付けのガイドラインについては、データシートを参照してください。
詳細なピン配置データはありません: BQ4850YMA-85.
詳細は データシート をご参照ください。
主な用途
BQ4850YMA-85 の用途: 6 件s: Industrial Data Logging, Embedded Measurement Instruments, Legacy Computer Time Base, Telemetry and Communications Equipment, Process-Control Terminals, Secure Logging and Access Records.
Industrial Data Logging
The BQ4850YMA-85 fits industrial data loggers that must preserve timestamps and process records across mains-power interruptions. Its verified 512Kx8 NVSRAM stores data locally, while the RTC supplies calendar information in BCD using a 24-hour HH MM SS format. A controller can read and update the module through its parallel interface instead of adding a separate RTC and SRAM. The integrated power-fail circuit and battery are especially useful for warning logic or preserving state during shutdown. Before deployment, verify operating temperature, memory endurance, battery life, and the complete power-fail timing from the manufacturer datasheet because those values are not present in the supplied snippets.
おすすめ
Embedded Measurement Instruments
The BQ4850YMA-85 is appropriate for measurement instruments requiring event timestamps and retained configuration records. The parallel interface fits a microprocessor bus, and the integrated 512Kx8 NVSRAM reduces the number of external timing and storage components. Recorded measurements can be associated with BCD calendar data while configuration or calibration information remains available after power removal. The 32-DIP through-hole format also suits legacy instrument platforms and socketed serviceability. Firmware must poll status rather than assume every read is atomic, and engineers should confirm address mapping, access timing, and hold requirements against the current Texas Instruments datasheet before laying out a replacement board.
おすすめ
Legacy Computer Time Base
The BQ4850YMA-85 can provide a battery-backed time base for legacy parallel-bus equipment that must maintain calendar information independently of its processor. Its x8 SRAM-compatible pin arrangement is useful for systems already organized around industry-standard memory interfaces, while the RTC registers add seconds-through-years timekeeping. The module combines the crystal, SRAM, battery, and power-fail circuit in one 32-DIP device. Integration reduces board area compared with separate clock and memory components, but firmware must treat address decoding and command timing carefully. Do not interchange the device solely on bus width; register commands, write behavior, alarm functions, and retained-memory semantics also need verification.
おすすめ
Telemetry and Communications Equipment
The BQ4850YMA-85 is suitable for communication equipment that must time-stamp events and retain operational records when power fails. Its real-time clock provides date and time in a compact BCD format, while 512Kx8 NVSRAM capacity can hold local queues, counters, or configuration snapshots. The parallel interface allows connection to a host processor bus rather than consuming a serial peripheral. During an outage, the integrated power-fail function can support orderly state preservation, although the detailed warning and switchover timing must be taken from the manufacturer document. For communications products, engineers should also validate oscillator behavior, supply tolerances, and firmware handling of invalid or partially updated calendar values.
おすすめ
Process-Control Terminals
The BQ4850YMA-85 can support process-control terminals that need event ordering, alarm history, and retained operating parameters. The RTC counts seconds through years, allowing the controller to annotate process events, while NVSRAM preserves critical records during a power interruption. Its RAM-like clock access supports practical integration into legacy parallel control architectures. The integrated battery and power-fail control are useful for brownout and shutdown handling, but firmware should account for the time available before supply collapse and validate every recovered record after startup. Qualification for a specific process environment requires the operating-temperature range, endurance data, and applicable industrial compliance records, none of which are verified in the supplied search data.
おすすめ
Secure Logging and Access Records
The BQ4850YMA-85 can provide timestamped local records in access-control and secure-logging systems where event order must survive a power interruption. Its 512Kx8 NVSRAM holds a modest ring buffer or audit segment, while the RTC supplies calendar and time information for each event. The 32-DIP package is practical for established security panels designed around through-hole modules and may simplify maintenance replacements. The design must still protect access to the memory map, define tamper-response behavior outside the IC's scope, and validate write integrity during unexpected power loss. Since the supplied data does not provide endurance or data-retention specifications, production security designs should obtain those limits directly from the current manufacturer datasheet.
おすすめ
おすすめ製品の概要
エンジニアリング参考データ: BQ4850YMA-85 — 比較、設計ガイダンス、コンプライアンス情報。
選定ガイド
代替品との比較
| パラメータ | この製品 | BQ4850YMA-85N |
|---|---|---|
| Package | 32-DIP module | 32-DIP module |
| Brand | Texas Instruments | Texas Instruments |
| Product Type | RTC module with 512Kx8 NVSRAM | Parallel 32-DIP RTC module |
| Supply Voltage Range | 4.5 V to 5.5 V | 4.5 V to 5.5 V |
| Interface | Parallel | Parallel |
主な差別化要因
- Integrates timekeeping and retained storage in one module （vs Separate SRAM and RTC implementation)
- Maintains calendar timing in BCD （vs Software-timestamp-only systems)
- Uses an established parallel memory-style interface （vs Serial RTC modules)
設計ノート
Do not treat the BQ4850YMA-85 as a generic x8 SRAM when writing replacement firmware. The verified description confirms RAM-like clock access, but RTC commands, address interpretation, status behavior, and power-fail semantics remain device-specific. Obtain the manufacturer register map and validate reads, writes, alarm operations, and startup defaults on hardware before releasing code.
Design the supply and backup paths around the verified 4.5 V to 5.5 V operating range. Confirm from the manufacturer datasheet which pins receive normal and backup supply, their allowed sequencing, and the voltage present during battery operation. Decoupling, ground return, and power-fail routing should be checked against the reference circuit; the supplied search data does not provide capacitor values or battery chemistry.
Use the verified 32-DIP module format, 0.610 inch or 15.49 mm wide, when defining connector and board footprints. Keep the parallel data and address routing away from noisy analog or switching nodes, provide a solid ground plane, and route the crystal, supply, and backup-capable pins according to the manufacturer layout guidance. Verify every pin name and signal direction from the complete package drawing because it is absent from the supplied data.
Treat time and retained-memory reads as potentially multi-step operations. The verified format uses BCD and 24-hour time, so firmware should convert it deliberately and define behavior for invalid values, oscillator-stop flags, and interrupted writes. The supplied data does not report read atomicity, oscillator accuracy, write endurance, or battery life; those limitations must be resolved from the current Texas Instruments datasheet.
コンプライアンス情報
No verified compliance declarations were included in the supplied target-product data.
