This document describes the features of the M41T56 512-bit (64-bit x8) Serial Access TIMEKEEPER® SRAM, which was released on June 24, 2004. The product has a supply voltage of 5V ±10%, counters for seconds, minutes, hours, day, date, month, years, and century, year 2000 compliance, software clock calibration, automatic power-fail detect and switch circuitry, compatibility with I2C bus, 56 bytes of general purpose RAM, ultra-low battery supply current of 450nA, low operating current of 300µA, operating temperature range of -40°C to 85°C, automatic leap year compensation, and a special software programmable output.
The M41T56 TIMEKEEPER® SRAM provides 512 bits (64 words × 8 bits) of static CMOS memory with an integrated 32.768 kHz oscillator for clock/calendar functions. It features a two‑wire bi‑directional bus (SDA/SCL) for serial data transfer, automatic power‑fail detection, and battery backup using a small lithium coin cell.
The device operates from a 5 V supply (±10 %) with ultra‑low battery current (450 nA) and low active current (300 µA). It operates over –40 °C to 85 °C, supports automatic leap‑year compensation, and is available in 8‑lead SOIC or 28‑lead SNAPHAT packages.
| Supply voltage | 5 V ±10 % |
|---|---|
| Battery supply current | 450 nA |
| Operating current | 300 µA |
| Operating temperature | –40 °C to 85 °C |
| Memory size | 512 bits (64 × 8) |
| Oscillator frequency | 32.768 kHz |
| Data retention (battery backup) | >10 years with 50 mAh, 3 V lithium cell |
| Package options | 28‑lead SOIC and SNAPHAT® TOP |
It operates from a 5 V supply with a tolerance of plus or minus 10 %.
Data can be retained for more than 10 years when powered by a 50 mAh, 3 V lithium coin cell.
Yes, the device includes automatic leap‑year compensation.