This document describes the features and characteristics of the M48T37Y and M48T37V products. These products are chips that integrate ultra-low power SRAM, real-time clock, battery, and power-fail control circuit. They feature a frequency test output, year 2000 compliance, automatic power-fail chip deselect and write protection, watchdog timer, programmable alarm output, etc. They also provide their respective operating voltage ranges and packaging forms.
The M48T37Y/V combines a 32 Kbyte (256 Kbit) static RAM with a real‑time clock, power‑fail detection, watchdog timer and battery‑low flag. It is supplied in a 44‑lead SOIC (SOH44) package that mates with a separate SNAPHAT top housing containing the battery and crystal.
The device operates from 4.5‑5.5 V (M48T37Y) or 3.0‑3.6 V (M48T37V), supports a wide temperature range, and provides programmable alarm and clock calibration features. Detailed timing parameters, pin functions and mechanical dimensions are listed in the following sections.
| Memory size | 256 Kbit (32 Kbit x8) |
|---|---|
| Supply voltage (M48T37Y) | 4.5 V to 5.5 V |
| Supply voltage (M48T37V) | 3.0 V to 3.6 V |
| Package type | 44‑lead SOIC (SOH44) with SNAPHAT top |
| Operating temperature range | -40 °C to 85 °C (or 0 °C to 70 °C) |
| Read cycle time | 70 ns to 100 ns |
| Watchdog timer | Included |
| Battery low flag | Included |
The SNAPHAT housing is inserted after the SOIC reflow process to avoid damage to the battery and crystal.
The read cycle time is specified as 70 ns to 100 ns.
Yes, the M48T37Y/V includes a watchdog timer.