STMicroelectronics M48T37Y-70MH6F

Overview

M48T37Y-70MH6F from STMicroelectronics is a 256 Kbit (32 K × 8) battery-backed TIMEKEEPER® SRAM integrating ultra-low-power real-time clock, power-fail control, watchdog timer, and microprocessor reset-operating at 4.5–5.5 V with VPFD = 4.2–4.5 V and crystal accuracy ±20 ppm over –40 to +85 °C. It delivers non-volatile timekeeping and memory retention for industrial control panels requiring tamper-resistant timestamping and fail-safe data logging.

For engineers reviewing the M48T37Y-70MH6F datasheet, M48T37Y-70MH6F pinout, M48T37Y-70MH6F application, or M48T37Y-70MH6F equivalent, this device supports battery-backed RTC+SRAM co-location in space-constrained embedded systems, with programmable alarm interrupt, frequency test output for software calibration, and automatic write-protection during VCC brownout.

Technical Context

The M48T37Y-70MH6F integrates a 32,768 Hz quartz oscillator, BiPORT™ dual-port SRAM array (32,752 × 8), voltage-sense switching circuitry, and VPFD-triggered power-fail logic that disconnects VCC and engages the SNAPHAT® lithium cell within 10 µs when VCC drops below 4.2 V. Its clock registers (7FF1h–7FFFh) store BCD-formatted century, year, month, date, day, hour, minute, and second, updated once per second by dedicated hardware-not software polling.

It implements three distinct power modes: active VCC operation (tAVQV ≤ 70 ns), seamless battery backup (≥7 years at 25 °C), and power-deselect (high-Z I/O, write-protected SRAM). The IRQ/FT pin serves dual function: open-drain alarm interrupt or 32.768 kHz frequency test output, configurable via register bit FT (D4 of 7FFCh).

Key Specifications

Pinout & Package

44-pin SOIC (SOH44) package with gold-plated top/bottom sockets for direct mating with SNAPHAT® housing (e.g., M4T28-BR12SH); SNAPHAT® contains integrated 32.768 kHz crystal and 48 mAh lithium coin cell. Package enables post-reflow assembly to avoid thermal damage to battery/crystal.

Key Features

Applications

Equivalent & Alternatives

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

Compared with DS1307+DS1243, M48T37Y-70MH6F reduces component count and improves reliability via monolithic integration and hardware VPFD; versus M48T59Y-70MH6F, it trades memory capacity for lower cost and smaller footprint in resource-constrained designs.

Availability

M48T37Y-70MH6F is available at Aetrix Electronics and suitable for industrial PLC HMIs, medical infusion pumps, smart energy meters, and telecom base station controllers requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for M48T37Y-70MH6F 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.

M48T37Y-70MH6F belongs to the TIMEKEEPER® family-engineered specifically for embedded systems needing guaranteed timekeeping integrity, data retention during power loss, and minimal external components for RTC+SRAM functionality.

FAQ

What is the purpose of the SNAPHAT® housing and how is it installed?

The SNAPHAT® housing (e.g., M4T28-BR12SH) contains the 32.768 kHz crystal and 48 mAh lithium coin cell, and mounts directly onto the SOH44 SOIC package after surface-mount reflow. Its keyed mechanical design prevents reverse insertion, and gold-plated sockets ensure reliable electrical contact without soldering-protecting the battery and crystal from thermal damage during PCB assembly.

How does the VPFD feature prevent data corruption during power loss?

When VCC falls into the 4.2–4.5 V window, the internal voltage-sense circuit asserts automatic write protection-placing all I/O pins in high-impedance state and disabling SRAM writes within 10 µs. This occurs before VCC reaches levels where partial writes could corrupt memory contents, eliminating need for external supervisor ICs in brownout scenarios.

Can the alarm function operate while the device is powered solely by the battery?

Yes-the Alarm in Battery Backup Mode Enable (ABE) bit (D2 of register 7FF6h) allows the alarm interrupt to remain fully functional during battery-only operation. When enabled, the IRQ/FT pin asserts active-low upon match of alarm registers (7FF2h–7FF5h) with current time-even with VCC removed-supporting low-power wake-up use cases.

What is the significance of the frequency test (FT) output on the IRQ/FT pin?

The FT bit (D4 of register 7FFCh) configures IRQ/FT to output a clean, calibrated 32.768 kHz square wave instead of alarm interrupt. This enables firmware-based oscillator calibration by comparing measured period against known reference, compensating for crystal aging or temperature drift without external test equipment.