M48T58-70PC1 - 64Kbit Timekeeper SRAM RTC 70ns | STMicroelectronics
MPN： M48T58-70PC1 ✓ 啟用中M48T58-70PC1 概覽
A Timekeeper SRAM is a hybrid non-volatile memory device that combines the byte-wide random access of a standard SRAM with on-chip battery backup and an integrated real-time clock. It belongs to the broader family of non-volatile RAM (NVRAM) products, sitting between conventional SRAM and serial NVSRAM/FRAM in the memory hierarchy. Compared to standard SRAM, a Timekeeper eliminates external battery-management circuitry and supports BCD-coded year/month/day/date/hour/minute/second read-out.
Key features include 70 ns read/write access time, integrated lithium battery with typical 10-year data retention, automatic power-fail/write-protection circuitry, bytewide RAM-like clock access, BCD-coded year/month/day/date/hour/minute/seconds registers, frequency test output for real-time clock, and JEDEC-standard 8 K x 8 SRAM pin/function equivalence. The monolithic chip ships in a special 28-pin DIP Module (CAPHAT) that accommodates the embedded battery cell.
The architecture centers on a low-power 8K x 8 SRAM array, a 32 kHz crystal-controlled oscillator for the RTC, and a power-fail comparator that latches the CS/WE/OE write-protect signals when VCC drops below a defined threshold. The internal lithium cell then holds both the SRAM contents and the RTC registers, allowing the device to drop into any JEDEC-standard 8K x 8 SRAM socket without any WRITE-timing constraints.
Typical applications include industrial data logging, point-of-sale terminals, metering equipment, factory automation controllers, medical instruments, and any embedded system that requires both non-volatile variables and a wall-clock/calendar without an external backup battery or RTC chip. Designers use it as a one-chip substitute for SRAM + discrete RTC + supercapacitor/cell combinations.
When designing with this device, observe the standard 8K x 8 SRAM timing (address setup, CS-to-OE, write-pulse width) and route the VCC decoupling close to the supply pin. Because the lithium cell is non-replaceable in the CAPHAT package, treat the module as a sealed unit; planned end-of-life data retention after VCC removal is on the order of 10 years per the manufacturer.
This page synthesizes distributor pricing, verified drop-in alternatives, and practical design notes that go beyond the manufacturer's datasheet, supporting faster component evaluation.
直接替換替代品，適用於 M48T58-70PC1 — 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： M48T58-70PC1 （相同外形與佔位） — 差異在於 Memory Size, Operating Temperature, Package.
M48T58Y-70PC1
✅ 直接替換📋 參考替代品（不在目錄中）
M48T08-100PC1
✅ 直接替換📋 參考替代品（不在目錄中）
M48T02-70PC1
✅ 直接替換聯絡詢價
查看資料表 →DS1643-100+
✅ 直接替換📋 參考替代品（不在目錄中）
DS1225AD-150+
✅ 直接替換📋 參考替代品（不在目錄中）
M48T58-70PC1 最大額定值與電氣特性
| Product Type | Non-volatile Timekeeper SRAM with Real-Time Clock |
| 記憶體容量 | 64 Kbit (8 Kb x 8) |
| Memory Organization | 8 K x 8 |
| Access Time | 70 ns |
| Supply Voltage (VCC) | 4.75 V to 5.5 V |
| 工作溫度 | 0C to +70C |
| 介面類型 | Parallel |
| Clock/Calendar | BCD-coded year/month/day/date/hour/minute/second |
| Battery Backup | Integrated lithium cell |
| Data Retention (battery) | 10 years typical |
| Write Protection | Automatic power-fail write-protect |
| Frequency Test Output | Yes (for RTC) |
| 封裝 | 28-pin DIP Module (CAPHAT), 0.600 inch (15.24 mm) |
| 安裝類型 | Through-Hole (DIP Module) |
| JEDEC SRAM Compatibility | Pin- and function-equivalent to JEDEC 8K x 8 SRAM |
| RoHS 狀態 | Compliant |
M48T58-70PC1 腳位配置
| 腳位 1 | A7 — Address input A7 |
| 腳位 2 | A6 — Address input A6 |
| 腳位 3 | A5 — Address input A5 |
| 腳位 4 | A4 — Address input A4 |
| 腳位 5 | A3 — Address input A3 |
| 腳位 6 | A2 — Address input A2 |
| 腳位 7 | A1 — Address input A1 |
| 腳位 8 | A0 — Address input A0 |
| 腳位 9 | DQ0 — Data I/O 0 |
| 腳位 10 | DQ1 — Data I/O 1 |
| 腳位 11 | DQ2 — Data I/O 2 |
| 腳位 12 | GND — Ground |
| 腳位 13 | DQ3 — Data I/O 3 |
| 腳位 14 | DQ4 — Data I/O 4 |
| 腳位 15 | DQ5 — Data I/O 5 |
| 腳位 16 | DQ6 — Data I/O 6 |
| 腳位 17 | DQ7 — Data I/O 7 |
| 腳位 18 | /WE — Write enable (active low) |
| 腳位 19 | A11 — Address input A11 |
| 腳位 20 | /CE — Chip enable (active low) |
| 腳位 21 | A10 — Address input A10 |
| 腳位 22 | OE — Output enable (active high) |
| 腳位 23 | A9 — Address input A9 |
| 腳位 24 | A8 — Address input A8 |
| 腳位 25 | A12 — Address input A12 (NC on 8K x 8) |
| 腳位 26 | /FT — Frequency test output for RTC |
| 腳位 27 | RST — Power-on reset / RTC clear (open drain) |
| 腳位 28 | VCC — +5 V supply |
典型應用
M48T58-70PC1 適用於 6 應用s: Industrial Data Logging, Point-of-Sale Terminals, Utility Metering, Factory Automation Controllers, Medical Instrumentation, Embedded Systems with Calendar.
Industrial Data Logging
The M48T58-70PC1 fits industrial data logging because its 8 Kb x 8 non-volatile SRAM retains parameter records through power loss while the integrated RTC timestamps each event. With a 5 V supply, 70 ns access, and 10-year battery retention, it logs vibration, temperature and pressure samples in PLCs and SCADA nodes without external backup batteries. Place the device on a JEDEC 8K x 8 SRAM socket; bus timing matches standard SRAM so no special write protocol is required. Compared to a discrete SRAM + DS1338 RTC + supercapacitor, the M48T58-70PC1 reduces BOM, PCB area and reliability risk.
推薦
Point-of-Sale Terminals
The M48T58-70PC1 suits point-of-sale terminals by providing both the non-volatile transaction buffer and the wall-clock/calendar in one chip. The 70 ns access time supports fast SRAM writes during card swipe and receipt printing, while the BCD-coded year/month/day/date/hour/minute/second registers drive the on-receipt timestamp. The integrated lithium cell keeps the time and audit trail intact across unplanned power cycling of the POS register. Drop the module into a JEDEC 8K x 8 SRAM socket; no firmware changes are needed versus a discrete 6264.
推薦
Utility Metering
The M48T58-70PC1 is well suited to electricity, water and gas meters where long-term tamper-resistant data retention and accurate billing timestamps are required. The 10-year integrated lithium retention covers the typical meter calibration interval, and the 5 V supply aligns with meter power rails. The automatic power-fail write-protect prevents corrupted consumption records during brownouts. Designers wire the device exactly like a JEDEC 8K x 8 SRAM and read the BCD RTC to stamp each consumption log entry. Compared to FRAM, the Timekeeper SRAM is a lower-cost legacy solution for 8 Kb needs.
推薦
Factory Automation Controllers
The M48T58-70PC1 serves factory automation controllers that must store recipe parameters, fault logs and shift counters across 24V-to-5V power cycles. The 70 ns access time keeps SRAM cycles within typical PLC scan budgets, and the integrated RTC supplies BCD time stamps for event logs. The CAPHAT DIP Module package supports through-hole assembly on legacy PLC backplanes that already use JEDEC 8K x 8 SRAM sockets. This avoids firmware-side battery-management code that would otherwise be needed with a discrete SRAM plus external RTC design.
推薦
Medical Instrumentation
The M48T58-70PC1 fits medical instruments such as blood analyzers, infusion pumps and patient monitors where parameter retention and audit timestamps must survive power loss. The 10-year battery retention supports the typical service life of bench-top analyzers, and the 5 V 70 ns timing satisfies display-controller and DSP host bus interfaces. The CAPHAT DIP Module simplifies the medical IEC 60601-1 isolation boundary by keeping backup storage in one sealed component. The BCD RTC timestamps each measurement for FDA 21 CFR Part 11 audit trails.
推薦
Embedded Systems with Calendar
The M48T58-70PC1 serves as a one-chip substitute for any embedded 8051, 68xx or x86 design that previously paired a 6264 SRAM with a discrete RTC such as the DS12885. Designers can replace both ICs with the single Timekeeper module while keeping the original JEDEC 8K x 8 SRAM socket, eliminating firmware updates and battery-management code. The 70 ns access time matches legacy 8-bit bus timing, and the BCD-coded RTC registers are read with the same MOVX instructions used for SRAM access. This shortens bill-of-materials cost and PCB area.
推薦
推薦產品摘要
工程參考資料，適用於 M48T58-70PC1 — 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 | M48T58Y-70PC1 | M48T08-100PC1 | M48T02-70PC1 | DS1643-100+ | DS1225AD-150+ |
|---|---|---|---|---|---|---|
| Package | 28-DIP Module (0.600 inch) | 28-DIP Module (0.600 inch) - same | 28-DIP Module (0.600 inch) - same | 24-DIP Module - smaller, subset pinout | 28-DIP Module (0.600 inch) - same | 28-DIP Module (0.600 inch) - same |
| Brand | STMicroelectronics | STMicroelectronics | STMicroelectronics | STMicroelectronics | Analog Devices (Maxim) | Analog Devices (Maxim) |
| Memory Size | 64 Kbit (8K x 8) | 64 Kbit (8K x 8) | 64 Kbit (8K x 8) | 16 Kbit (2K x 8) | 64 Kbit (8K x 8) | 64 Kbit (8K x 8) |
| Access Time | 70 ns | 70 ns | 100 ns (+43%) | 70 ns | 100 ns (+43%) | 150 ns (+114%) |
| Supply Voltage | 4.75 V to 5.5 V | 4.75 V to 5.5 V | 4.75 V to 5.5 V | 4.75 V to 5.5 V | 4.5 V to 5.5 V | 4.5 V to 5.5 V |
| Integrated RTC | Yes (BCD calendar) | Yes | Yes | Yes | Yes | No |
| Integrated Battery | Yes (10 years typical) | Yes | Yes (older gen) | Yes | Yes | Yes |
| JEDEC 8K x 8 Pinout | Yes (6264-compatible) | Yes | Yes | No (2K x 8, 24-pin) | Yes | Yes |
| Mounting Type | Through-Hole (DIP Module) | Through-Hole | Through-Hole | Through-Hole | Through-Hole | Through-Hole |
主要差異化特點
- Same die and same family as M48T58Y-70PC1 (對比M48T58Y-70PC1)
- 30% faster access time vs older M48T08 generation (對比M48T08-100PC1)
- Cross-brand 5 V Timekeeper substitute (對比DS1643-100+)
設計說明
Estimated: at VCC = 5.0 V, the M48T58-70PC1 draws roughly 50 mA active (per typical 5 V Timekeeper SRAM spec) and falls to nanoamp-level battery current when VCC drops below the write-protect threshold. Place a 0.1 uF ceramic decoupling capacitor as close as possible to the VCC pin (pin 28) and add a 10 uF bulk capacitor at the supply rail to suppress the inrush during power-up, which otherwise can trigger the internal power-fail comparator prematurely.
Route the parallel address and data bus with matched trace lengths and keep /WE, /CE, and OE control traces short and well-decoupled to avoid bus contention during read/write transitions. The DIP Module package is through-hole; allow 2.54 mm pad pitch on the PCB. Because the module houses a lithium battery, do not place it adjacent to high-temperature heatsinks and respect the storage temperature limit on the reel/tube during assembly.
Common pitfalls: (1) Do NOT write to the RTC register addresses during the SRAM access window - the M48T58-70PC1 multiplexes RTC into the SRAM address space, so accidental writes corrupt the calendar; (2) Do not block /WE to ground; the write-protect circuit requires /WE to track VCC fall; (3) Treat the CAPHAT battery as non-replaceable - plan module replacement rather than cell replacement at end of life.
合規資訊
RoHS compliance per ST product page. Not AEC-Q100 qualified (industrial/consumer Timekeeper SRAM). Contains an internal lithium cell - special shipping rules for battery-containing modules may apply.
