M48T35, M48T35Y are TIMEKEEPER® SRAMs produced by Microchip Technology with 256 Kbit (32Kb x8) capacity, which integrate an ultra-low-power SRAM, real-time clock, power-fail control circuit and battery. It features byte-wide RAM-like clock access, BCD coded year, month, day, date, hours, minutes and seconds, frequency test output for real-time clock, automatic power-fail chip deselect and write protection, write protect voltages of 4.5V ≤ VPFD ≤ 4.75V, 4.2V ≤ VPFD ≤ 4.5V, self-contained battery and crystal in the CAPHAT DIP package, SOIC package provides direct connection to a SNAPHAT housing containing the battery and crystal, SNAPHAT® housing (battery and crystal) is replaceable, and is pin and function compatible with JEDEC standard 32Kb x8 SRAMs.
The M48T35/M48T35Y TIMEKEEPER® SRAM is a 32 Kb × 8 non‑volatile static RAM with an integrated real‑time clock, battery, and crystal in a single package. It is pin‑compatible with JEDEC standard 32 Kb × 8 SRAMs and can be used in DIP or SOIC form factors.
The device includes ultra‑low‑power operation, power‑fail deselect and write‑protect circuitry, and a BCD‑coded clock that can be halted via control‑register bits. Key specifications include a power‑fail deselect voltage of 4.5‑4.75 V (M48T35) or 4.2‑4.5 V (M48T35Y), supply voltage range –0.3 V to 7 V, and data retention of at least 7 years at 25 °C.
| Power‑fail Deselect Voltage (VPFD) – M48T35 | 4.5 V ≤ VPFD ≤ 4.75 V |
|---|---|
| Power‑fail Deselect Voltage (VPFD) – M48T35Y | 4.2 V ≤ VPFD ≤ 4.5 V |
| Supply Voltage (VCC) | –0.3 V to 7 V |
| Input High Voltage (VIH) | 2.2 V + 0.3 V |
| Standby Supply Current (TTL) | 3 mA |
The power‑fail deselect voltage for the M48T35 is between 4.5 V and 4.75 V.
The device operates with a supply voltage from –0.3 V up to 7 V.