STMicroelectronics M48T12-200PC1

Overview

M48T12-200PC1 from STMicroelectronics is a 5.0 V, 16 Kbit (2 Kb × 8) TIMEKEEPER® SRAM integrating ultra-low-power static RAM, real-time clock, and power-fail control in a single CAPHAT™ DIP package. It delivers BCD-coded timekeeping (year/month/day/hour/minute/second), ±1 minute/month accuracy at 25 °C, software-controlled clock calibration, and automatic battery switchover at VPFD = 4.2–4.5 V. It serves as non-volatile memory and RTC in industrial control panels requiring long-term data retention during AC loss.

For engineers reviewing the M48T12-200PC1 datasheet, M48T12-200PC1 pinout, M48T12-200PC1 application, or M48T12-200PC1 equivalent, this page provides verified timing register mapping, VPFD trip point validation, BYTEWIDE™ SRAM access behavior, and JEDEC 2K×8 compatibility confirmation - all critical for legacy system replacement and battery-backed time-critical firmware storage.

Technical Context

The M48T12-200PC1 integrates a 2048 × 8 BiPORT™ SRAM array with a quartz oscillator (32.768 kHz), voltage-sense circuitry, and lithium battery switching logic on one die. Its clock registers (7F8h–7FFh) are memory-mapped SRAM locations updated once per second by dedicated hardware - not software-timed reads - ensuring atomic time capture without CPU intervention.

Power management is hardware-autonomous: when VCC drops into the 4.2–4.5 V VPFD window, the device enters write-protected deselect mode; below ~3 V, it seamlessly switches to battery backup while maintaining clock operation and SRAM data integrity for ≥10 years. The BOK (Battery OK) flag indicates lithium cell health and blocks writes until cleared post-power-up.

Key Specifications

Pinout & Package

Package: PCDIP24 - 24-pin plastic dual in-line package with integrated lithium battery and 32.768 kHz crystal (CAPHAT™).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar real-time clock + non-volatile SRAM applications.

Compared with DS1642-200IND+, M48T12-200PC1 reduces component count and layout complexity via integrated battery/crystal, while matching VPFD behavior and JEDEC compatibility; versus M48T35Y-200PC1, it offers proven 10-year retention at lower cost and smaller footprint where extended memory or alarms are unnecessary.

Availability

M48T12-200PC1 is available at Aetrix Electronics and suitable for industrial control panels, medical diagnostics, telecom shelf management, and smart energy metering requiring stable component supply across extended product lifecycles.

Supply support for M48T12-200PC1 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing microcontrollers, power management ICs, sensors, and analog/mixed-signal devices for industrial, automotive, and consumer markets.

The M48T12 belongs to ST's TIMEKEEPER® family - engineered specifically for battery-backed timekeeping and non-volatile data retention in mission-critical infrastructure where power interruption resilience is mandatory.

FAQ

What is the function of the BOK (Battery OK) flag, and how is it used?

The BOK flag indicates lithium battery health after power-up. When set, it blocks the first WRITE attempt to prevent data corruption from insufficient backup voltage. Software must read any memory location, verify its complement, then write the complement back to clear the flag. Once cleared, normal SRAM operation resumes - no manual reset or external signal is needed.

How does the M48T12-200PC1 handle leap-year calculation?

The M48T12-200PC1 automatically corrects for 28-, 29- (leap year), 30-, and 31-day months using internal logic tied to the BCD-encoded date register. Leap-year handling is valid through year 2100 and requires no software intervention - the hardware updates the day-of-month counter correctly upon rollover from February 28.

Can the M48T12-200PC1 be used as a direct replacement for standard 2K×8 SRAMs?

Yes - it is pin- and function-compatible with JEDEC-standard 2K×8 SRAMs (e.g., 2114, 6116). All control signals (E, G, W), address/data bus timing, and DC characteristics match. During normal VCC operation, it behaves identically; battery backup and clock registers are transparent unless accessed at addresses 7F8h–7FFh.

What is the significance of the "200" in the part number M48T12-200PC1?

The "200" denotes the maximum access time specification: 200 ns. This speed grade ensures compatibility with legacy 5 V systems using 8051, Z80, or 68000-based controllers where memory timing margins are tight. It matches the −200 speed bin defined in ST's Doc ID 2410 Rev 9, Table 3 and Table 4.