BQ4285S-SB2G4 - Real-Time Clock with NVRAM Control | TI
部品番号: BQ4285S-SB2G4 ✗ 生産終了BQ4285S-SB2G4 概要
A real-time clock, or RTC, is a clock-and-timing integrated circuit that maintains time independently of the main processor. The RTC category belongs to the clock-and-timing hierarchy, which also includes timers, oscillators, and timing controllers. An RTC with NVRAM control can maintain calendar information while providing a mechanism for retaining or managing small amounts of volatile data across resets or controlled power transitions.
The BQ4285S-SB2G4 provides a 114-byte parallel interface and uses 24 SOIC pins. The verified package data describes a 0.295-inch, 7.50 mm-wide SOIC with a gull-wing terminal form and rectangular package shape. The verified date-format information identifies support for YY-MM-DD-dd and BCD representations, which is useful for systems requiring readable calendar data or binary-coded decimal processing.
The family datasheet pin listing includes oscillator-related X1 and X2 connections together with address signals AD0 through AD7. These address lines are relevant when the RTC registers are mapped into a wider system bus or memory-style interface. The parallel interface distinguishes this device from compact serial RTCs and makes it appropriate for platforms whose processor bus can accommodate the additional address and data routing.
Typical uses include industrial controllers, embedded instruments, data-acquisition equipment, and systems that require persistent calendar data, scheduled events, or centralized timekeeping. The 24-pin SOIC footprint also supports conventional surface-mount PCB assembly. Designers should verify the complete electrical limits, oscillator requirements, alarm behavior, and NVRAM-control implementation against the manufacturer datasheet before release.
For a new design, begin with the manufacturer datasheet rather than relying only on distributor summaries. Confirm supply voltage, current consumption, oscillator frequency, accuracy, alarm behavior, timing characteristics, and register access details. Verify the PCB land pattern and decoupling requirements for the exact 24-SOIC package, especially where long parallel traces or slow bus edges could introduce signal-integrity concerns.
This page combines the verified 114-byte parallel interface and 24-SOIC package information with structured sourcing, comparison, and design guidance. It also distinguishes verified catalog facts from parameters that still require confirmation from the manufacturer datasheet, helping engineers build a reliable RTC design without treating incomplete distributor metadata as a complete electrical specification.
ドロップイン代替品: BQ4285S-SB2G4 — 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。
このシリーズのバリエーション
同一シリーズでドロップイン互換のモデル: BQ4285S-SB2G4 （同一形状・フットプリント） — 相違点: Package, Interface Type, Mounting Type, NVRAM Organization, Product Type.
BQ4285S-SB2TR
✅ ドロップイン価格はお問い合わせください
データシートを見る →BQ4285P-SB2
✅ ドロップイン価格はお問い合わせください
データシートを見る →DS14285SN
✅ ドロップイン📋 参考代替品（カタログ未掲載）
DS14285S+
✅ ドロップイン📋 参考代替品（カタログ未掲載）
DS1685SN-5
✅ ドロップイン📋 参考代替品（カタログ未掲載）
BQ4285S-SB2G4 仕様
| Device Type | Real-Time Clock (RTC) IC Clock/Calendar |
| Additional Function | NVRAM control |
| インターフェースタイプ | 114B parallel |
| パッケージ | 24-SOIC (0.295 inch, 7.50 mm width) |
| Number of Terminals | 24 |
| Package Code | SOP |
| Package Shape | Rectangular |
| Terminal Form | Gull wing |
| Temperature Grade | Commercial |
| Date Format | YY-MM-DD-dd, BCD |
| Oscillator Connection Pins | X1 and X2 |
| Address Signals | AD0 through AD7 |
BQ4285S-SB2G4 rectangular ピン配置ガイド
BQ4285S-SB2G4 (rectangular 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: BQ4285S-SB2G4.
詳細は データシート をご参照ください。
主な用途
BQ4285S-SB2G4 の用途: 6 件s: Industrial data-acquisition equipment, Embedded instrumentation and test equipment, Embedded controller timekeeping, Communications equipment, Scheduled industrial control, Battery-backed data retention.
Industrial data-acquisition equipment
The BQ4285S-SB2G4 fits industrial data-acquisition systems that require a dedicated calendar and real-time clock alongside measurement processing. Its verified 114-byte parallel interface provides a structured register-oriented connection for time, date, and related RTC functions, while the 24-SOIC package simplifies assembly on conventional industrial controller boards. The interface is especially useful when the host processor has a parallel memory-style bus. Designers should confirm supply limits, oscillator requirements, and register timing from the manufacturer datasheet before implementation. Compared with a serial RTC, the BQ4285S provides a wider address and data path, but it also requires more PCB routing and careful bus timing review.
おすすめ
Embedded instrumentation and test equipment
The BQ4285S-SB2G4 is suitable for embedded instrumentation, test equipment, and measurement platforms that must timestamp events with calendar information. The verified 114-byte parallel interface permits access to a larger RTC register set than compact serial-only calendar devices, while YY-MM-DD-dd and BCD formatting supports both operator-readable and binary-coded date processing. In a bench instrument, the RTC can provide a local time reference independent of the main application processor. The design trade-off is bus complexity: address signals AD0 through AD7 and the 24-pin SOIC footprint require more routing than an I2C or SPI RTC.
おすすめ
Embedded controller timekeeping
The BQ4285S-SB2G4 can serve as a dedicated timekeeping component in an embedded controller that must retain calendar information independently of its main processor. Its verified parallel architecture is advantageous for systems with a processor bus and register map, while the commercial temperature grade supports general commercial equipment. The BQ4285S family datasheet also identifies NVRAM control, making the device relevant to designs that need controlled retention behavior in addition to clock and calendar functions. Engineers must verify backup-power requirements, alarm timing, and reset behavior directly from the manufacturer documentation before treating it as a complete system timekeeper.
おすすめ
Communications equipment
The BQ4285S-SB2G4 can support communications equipment requiring a nonvolatile calendar reference and event timestamping. The verified 114-byte parallel interface allows a network controller or communications processor to access RTC registers through a bus-oriented architecture, while NVRAM control provides a retention-management function identified in the family documentation. This arrangement is useful in gateways, telemetry equipment, and industrial communication nodes where event logs must retain accurate dates. The designer should assess bus loading and signal integrity, particularly if the address and data paths are long or operate at slow edge rates.
おすすめ
Scheduled industrial control
The BQ4285S-SB2G4 is appropriate for industrial control equipment that performs scheduled operations based on real time. The verified calendar functions and BCD or readable date formats support chronological records, while the parallel RTC interface can be read by a central controller during supervisory tasks. Its 24-SOIC package allows assembly without a fine-pitch BGA footprint, which can simplify inspection and rework in lower-volume industrial products. Before deployment, verify alarm and timing resolution, oscillator stability, supply-voltage tolerance, and behavior during power interruption to ensure that the clock remains reliable across the expected operating environment.
おすすめ
Battery-backed data retention
The BQ4285S-SB2G4 can support battery-backed systems where time and limited retained data must remain available during main-power interruptions. The family description explicitly identifies NVRAM control, while the clock-and-calendar function preserves a time reference independent of the host processor. That combination is relevant to industrial terminals, metering equipment, and controllers that log events around unexpected power loss. The implementation must use the manufacturer-prescribed backup supply, oscillator, and capacitor arrangements. Exact backup-current figures, data-retention duration, and power-fail behavior were not present in the verified snippets and therefore require confirmation from the 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: BQ4285S-SB2G4 — 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 | BQ4285S-SB2TR | BQ4285P-SB2 | DS14285SN | DS14285S+ | DS1685SN-5 |
|---|---|---|---|---|---|---|
| Package | 24-SOIC (0.295 inch, 7.50 mm width) | 24-SOIC (0.295 inch, 7.50 mm width) | 24-SOIC (0.295 inch, 7.50 mm width) | 24-SOIC class | 24-SOIC class | 24-SOIC class |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Maxim Integrated | Maxim Integrated | Maxim Integrated |
| Device Function | Real-time clock and calendar with NVRAM control | Real-time clock and calendar with NVRAM control | Real-time clock family member | RTC comparison candidate | RTC comparison candidate | RTC comparison candidate |
| Number of Terminals | 24 | 24 | 24 | 24 | 24 | 24 |
主な差別化要因
- Explicit NVRAM-control function （vs DS14285SN)
- Verified 114-byte parallel interface （vs DS1685SN-5)
- Readable and BCD date-format support （vs DS14285S+)
- Same-manufacturer ordering option （vs BQ4285S-SB2TR)
設計ノート
Use the exact 24-SOIC land pattern from the manufacturer package drawing and maintain the documented pad spacing, body clearance, and copper-to-body clearance. The verified package is 0.295 inch, or 7.50 mm, wide, but the body width alone is not a complete footprint definition. Route the parallel address and data signals away from switching-node and high-current supply paths to reduce coupling.
Place the X1 and X2 oscillator network close to the device and follow the manufacturer layout guidance exactly. Keep the oscillator loop compact, use a common ground reference, and avoid routing clock signals beneath or beside noisy switching and high-current traces. Verify the required crystal or oscillator frequency and load capacitance from the BQ4285S family datasheet because those values were not included in the verified catalog snippets.
Review the host-bus timing for the 114-byte parallel interface, especially read/write turnaround, address setup, and data hold requirements. The verified data confirms a parallel interface and identifies AD0 through AD7, but it does not provide setup times, hold times, or propagation delays. Those limits must come from the datasheet, and the firmware should avoid polling faster than the published access timing.
Confirm the BQ4285S supply range, backup-supply arrangement, decoupling requirements, and current consumption from the manufacturer datasheet. If the RTC is backed by a separate source, validate start-up behavior and retention time across the complete power-loss and recovery sequence. Do not infer the battery chemistry, capacitor value, or backup-current budget from the verified distributor metadata.
コンプライアンス情報
The verified web results identify the target as a commercial-grade Texas Instruments RTC but do not provide explicit RoHS, REACH, AEC-Q100, lead-free, halogen-free, or conflict-minerals statements. These fields remain unknown rather than assumed.
