STMicroelectronics M48T35AV-10MH6E

Overview

M48T35AV-10MH6E from STMicroelectronics is a 3.3 V, 256 Kbit (32 K × 8) non-volatile TIMEKEEPER® SRAM integrating ultra-low-power static RAM, real-time clock, power-fail control circuitry, and on-board lithium battery and crystal in a CAPHAT™ DIP-28 package. It delivers BCD-coded timekeeping (year/month/day/hour/minute/second), battery low flag (BOK), frequency test output, and automatic WRITE protection during power failure with VPFD = 2.7–3.0 V. It is used in industrial control panels requiring persistent time-stamped logging during mains loss.

For engineers reviewing the M48T35AV-10MH6E datasheet, M48T35AV-10MH6E pinout, M48T35AV-10MH6E application, or M48T35AV-10MH6E equivalent, this page provides verified timing accuracy (±35 ppm at 25°C, improved to +1/–2 ppm with calibration), battery-backed data retention (>7 years), BYTEWIDE™ SRAM access compatibility, and JEDEC 32K×8 SRAM pin/function equivalence - critical for legacy socket replacement and fail-safe timekeeping design.

Technical Context

The M48T35AV-10MH6E integrates a 32,768 Hz quartz oscillator, BiPORT™ dual-port memory array, and voltage-sense switching circuitry on a single die. Its clock registers (7FF8h–7FFFh) reside in upper SRAM addresses and are updated once per second by dedicated clock logic - not direct counter reads - enabling atomic time capture without halting system operation.

Power management includes three distinct modes: active SRAM operation (VCC = 3.0–3.6 V), power-fail deselect (VPFD window: 2.7–3.0 V), and battery backup (VCC ≤ VSO). The BOK flag is latched at power-up if battery voltage falls below ~2.5 V, blocking first WRITE until cleared - ensuring time integrity before resuming write cycles.

Key Specifications

Pinout & Package

Package: PCDIP28 (600-mil plastic DIP) with integrated CAPHAT™ housing containing lithium button cell and 32.768 kHz quartz crystal.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar non-volatile timekeeping SRAM applications.

Compared with DS12887A-10+, the M48T35AV-10MH6E offers lower voltage operation, tighter base accuracy, and fully integrated timing - reducing system-level validation. Versus M48T35Y-10MH6E, it trades SMT flexibility for through-hole simplicity and guaranteed pre-assembled timing stability.

Availability

M48T35AV-10MH6E is available at Aetrix Electronics and suitable for industrial control panels, medical data loggers, point-of-sale terminals, and smart energy meters requiring stable component supply with guaranteed long-term timing integrity.

Supply support for M48T35AV-10MH6E 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, designing and manufacturing analog, MCU, power, and memory solutions for industrial, automotive, and consumer markets.

The TIMEKEEPER® product line delivers integrated non-volatile SRAM + RTC devices optimized for fail-safe time-critical data retention in industrial automation, medical instrumentation, and infrastructure equipment.

FAQ

What is the battery lifetime under continuous backup conditions?

The M48T35AV-10MH6E's integrated 48 mAh lithium cell sustains SRAM and RTC operation for a minimum of 7 years when VCC remains below VSO (typically ≤2.7 V). This rating assumes typical operating current of ~1.5 µA in battery mode and accounts for self-discharge. Battery voltage is monitored at power-up via the BOK flag to warn of depletion before data loss occurs.

How does the BYTEWIDE™ clock access work in practice?

TIMEKEEPER® registers occupy SRAM addresses 7FF8h–7FFFh. To read time, the host performs a standard memory READ at those locations - no I²C or SPI protocol needed. To set time, the WRITE bit (D7) in control register 7FF8h is set to '1' to halt updates, BCD values are written to 7FF9h–7FFFh, then the WRITE bit is cleared to '0' to commit changes to the clock counters within one second.

Can the M48T35AV-10MH6E be used in a 5 V system?

No - the M48T35AV-10MH6E is strictly a 3.3 V device with absolute maximum VCC of 3.6 V. Applying 5 V will damage the IC. For 5 V systems, consider the functionally similar but electrically incompatible DS12887A-10+, which requires level-shifting, external battery, and crystal - increasing board complexity and reducing long-term timing stability.

Is the CAPHAT™ package field-repairable if the battery depletes?

No - the CAPHAT™ DIP-28 package is hermetically sealed with non-replaceable internal battery and crystal. Once depleted, the entire unit must be replaced. For field-serviceable designs, ST offers the M48T35Y-10MH6E in SOH28 package with removable SNAPHAT® housing - allowing battery/crystal replacement without replacing the silicon die.