STMicroelectronics M48T02-150PC1

Overview

M48T02-150PC1 from STMicroelectronics is a 5.0 V, 16 Kbit (2 Kb × 8) non-volatile TIMEKEEPER® SRAM integrating ultra-low-power static RAM, real-time clock, and power-fail control circuitry in a single CAPHAT™ DIP package. It features BCD-coded timekeeping registers (year/month/day/hour/minute/second), ±1 minute/month typical clock accuracy at 25 °C, software-controlled calibration, automatic WRITE protection during V_CC brownout, and self-contained lithium battery + 32.768 kHz crystal. Used in industrial control panels for timestamped event logging under intermittent power.

For engineers reviewing the M48T02-150PC1 datasheet, M48T02-150PC1 pinout, M48T02-150PC1 application, or M48T02-150PC1 equivalent, key selection criteria include battery-backed RTC retention duration, BYTEWIDE™ SRAM compatibility with JEDEC 2K×8 sockets, VPFD voltage window (4.5–4.75 V), BOK flag behavior on power-up, and calibration register resolution (±5.35 s/month per LSB).

Technical Context

The M48T02-150PC1 integrates a BiPORT™ SRAM array and quartz oscillator on one die, with clock data mapped to memory-mapped registers at addresses 7F8h–7FFh. The clock control register (7F8h) includes READ/WRITE/STOP/FT bits and a 5-bit calibration field with sign bit, enabling ±31-step adjustment of oscillator timing via pulse blanking/splitting at the ÷256 stage.

Power management uses dual-threshold detection: VPFD (4.5–4.75 V) triggers write-protection and high-Z outputs; VSO (~3 V) initiates battery switchover. The BOK flag indicates low battery voltage post-power-up and blocks first WRITE until cleared by successful write operation - ensuring data integrity during backup power transition.

Key Specifications

Pinout & Package

Package: PCDIP24 - 24-pin plastic DIP with integrated CAPHAT™ battery and crystal.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar battery-backed RTC+SRAM applications.

Compared with DS1642-150+, M48T02-150PC1 reduces bill-of-materials and assembly risk via integrated battery/crystal; versus M48T35Y-150PC1, it delivers optimal cost-performance balance for applications needing only 2 KB of timestamped storage.

Availability

M48T02-150PC1 is available at Aetrix Electronics and suitable for industrial control panels, medical infusion pumps, point-of-sale terminals, and smart electricity meters requiring stable component supply with guaranteed 10-year battery retention and RoHS-compliant lead-free interconnects.

Supply support for M48T02-150PC1 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 automotive, industrial, and consumer markets.

The TIMEKEEPER® product line targets embedded systems requiring autonomous, long-life timekeeping with zero external components - specifically engineered for industrial automation, medical instrumentation, and energy metering where timestamp integrity is safety- or compliance-critical.

FAQ

What is the guaranteed data retention period for M48T02-150PC1 under continuous battery backup?

The M48T02-150PC1 guarantees ≥10 years of data and clock retention in battery-backup mode across the full operating temperature range (0–70 °C), based on integrated lithium button cell capacity and low-quiescent-current oscillator design. This value is measured under worst-case conditions and does not require periodic refresh or external power cycling.

How does the BOK (Battery OK) flag function during power-up sequences?

On power-up, the M48T02-150PC1 samples battery voltage and sets the BOK flag if it falls below the threshold. When set, the first attempted WRITE operation is blocked until the write succeeds, at which point the flag clears automatically. This prevents corrupted timestamps or log entries due to insufficient backup power during critical initialization.

Can the M48T02-150PC1 be used as a direct replacement for standard 2K×8 SRAMs without modifying existing firmware?

Yes - the M48T02-150PC1 is pin- and function-compatible with JEDEC-standard 2K×8 SRAMs. Standard READ/WRITE cycles access SRAM locations 000h–7F7h identically; TIMEKEEPER registers reside at 7F8h–7FFh and require no special timing, enabling drop-in replacement in most legacy designs with minimal firmware updates.

What is the purpose and behavior of the STOP bit in the seconds register (7F9h)?

The STOP bit (MSB of 7F9h) halts the 32.768 kHz oscillator to conserve battery during extended shelf life or storage. The device ships with STOP=1. Writing STOP=0 resumes oscillation within one second. While stopped, RTC registers retain last valid time but do not advance - preserving timestamp consistency across power-off periods.