M48T35 M48T35Y 5V, 256 Kbit (32 Kb x8) TIMEKEEPER® SRAM
The M48T35/Y TIMEKEEPER® RAM combines a 32 Kb × 8 static RAM with a real‑time clock that stores BCD‑coded year, month, day, date, hours, minutes and seconds. The device includes an ultra‑low‑power supply‑fail detection circuit that write‑protects the memory and switches to a backup battery when VCC drops.
Two package options are offered: a 28‑pin PCDIP with a CAPHAT housing that contains the crystal and a 48 mAh lithium battery, and a 28‑pin SOIC that mates with a separate SNAPHAT housing (available with 48 mAh or 120 mAh batteries). Both packages are pin‑compatible with JEDEC 32 Kb × 8 SRAMs.
| Memory capacity | 32 Kb × 8 (256 Kbit) |
|---|---|
| Supply voltage (VCC) – M48T35 | 4.75 V to 5.5 V |
| Write‑protect voltage (Vpep) – M48T35Y | 4.2 V < Vpep < 4.5 V |
| Clock data format | BCD‑coded year, month, day, date, hours, minutes, seconds |
| Ambient operating temperature | 0 °C to 70 °C (or 40 °C to 85 °C) |
| Battery capacity (CAPHAT / SNAPHAT) | 48 mAh (optionally 120 mAh) |
Eight clock bytes are provided at addresses 7FF8h‑7FFFh.