STMicroelectronics M48T201Y-70MH1E

Overview

M48T201Y-70MH1E from STMicroelectronics is a 5.0 V real-time clock (RTC) supervisor IC integrating RTC, watchdog timer, programmable alarm, square wave output, power-fail detection, and battery-backed SRAM interface control. It supports up to 512 K × 8 external low-power SRAM, provides year-2000-compliant date/time tracking with leap-year correction through 2100, and features VPFD = 4.1–4.5 V write-protect threshold. Used in industrial control panels for time-stamped event logging during main power loss.

For engineers reviewing the M48T201Y-70MH1E datasheet, M48T201Y-70MH1E pinout, M48T201Y-70MH1E application, or M48T201Y-70MH1E equivalent, key selection criteria include VCC=4.5–5.5 V operation, 44-pin SOIC package with SNAPHAT® top compatibility, battery-low flag signaling, microprocessor power-on reset validity in backup mode, and GCON/ECON-controlled external RAM enable timing.

Technical Context

The device implements a BiPORT™ memory architecture where TIMEKEEPER® registers (7FFF0h–7FFFFh) reside in upper SRAM address space and are accessed identically to standard SRAM bytes-no dedicated I²C/SPI interface. Clock updates occur once per second via internal oscillator, with calibration register (7FFF8h) enabling ±128 ppm fine-tuning.

Power management uses dual-threshold detection: VPFD (4.1–4.5 V) triggers write protection and RST assertion before switchover; VSO (≈3.0 V) initiates automatic battery backup via VOUT, sustaining RTC and SRAM with ≤100 µA supply at <0.3 V drop. GCON and ECON outputs are actively controlled during transients to prevent data corruption on external memory.

Key Specifications

Pinout & Package

44-pin SOIC (SOH44, 330 mil width), RoHS-compliant, lead-free second-level interconnect. Designed for direct mating with separate SNAPHAT® top (e.g., M4Txx-BR12SH) containing 32.768 kHz crystal and lithium coin cell - mounted post-reflow to avoid thermal damage.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar RTC supervisor applications.

Compared with DS12887A+, M48T201Y-70MH1E offers field-replaceable battery, flexible alarm modes, and SRAM control integration; versus PCF8583, it delivers native 5 V operation, hardware-based write protection, and zero-software RTC access - critical for deterministic industrial logging.

Availability

M48T201Y-70MH1E is available at Aetrix Electronics and suitable for industrial HMI logging, medical device timestamping, energy meter data buffering, and building automation controllers requiring stable component supply across extended product lifecycles.

Supply support for M48T201Y-70MH1E 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 specializing in automotive, industrial, and power management solutions, with over 40 years of analog and mixed-signal IC design expertise.

The M48T201Y-70MH1E belongs to ST's TIMEKEEPER® supervisor family, engineered specifically to convert standard SRAM into nonvolatile memory while delivering robust, battery-backed real-time clocking for mission-critical industrial and medical applications.

FAQ

What is the function of the VOUT pin?

VOUT supplies regulated backup current (≤100 µA at <0.3 V drop) to external SRAM during battery mode. It connects directly to the SRAM VCC pin when VCC falls below VSO, eliminating need for external regulators. Its voltage tracks VBAT minus internal diode drop, ensuring seamless transition without data loss.

How does the M48T201Y-70MH1E handle leap years?

The calendar logic automatically adjusts day-of-month for February (28 or 29 days) and applies Gregorian leap-year rules through year 2100. This behavior is hardwired in silicon - no firmware intervention or register programming is required. The century byte (7FFF1h) enables correct rollover from 1999 to 2000 and beyond.

Can the SQW output frequency be changed dynamically during operation?

Yes. The square wave frequency (1 Hz, 1.024 kHz, 4.096 kHz, or 8.192 kHz) is set by bits RS0–RS3 in register 7FFF0h and can be modified in real time via standard SRAM write cycles. No reset or oscillator restart is needed - the change takes effect on the next clock edge.

Is the SNAPHAT® top included with the M48T201Y-70MH1E order?

No. The SNAPHAT® housing (e.g., M4T12-BR12SH for 48 mAh) is ordered separately. The SOIC (M48T201Y-70MH1E) ships bare; the SNAPHAT top contains the 32.768 kHz crystal and lithium coin cell and mounts mechanically onto the SOIC after reflow soldering to avoid thermal damage.