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M48T35-70PC1

M48T35-70PC1

STMicroelectronics
Real Time Clock (RTC) IC Clock/Calendar Parallel 28-DIP Module (0.600", 15.24mm)
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Overview

The M48T35-70PC1 is a 256 Kbit (32 Kb x 8) non-volatile TIMEKEEPER SRAM that integrates a real-time clock, crystal, and lithium battery into a single 28-pin CAPHAT DIP package. It provides a complete solution for applications requiring persistent memory and timekeeping functionality without the need for external components. The device utilizes a parallel interface with a 70ns access time, making it compatible with many standard SRAM footprints.

Why Choose This Part

The integrated battery and crystal eliminate the need for complex PCB layout considerations and external component sourcing. It features a leap year-compensated calendar and is housed in a robust 28-pin PCDIP module that simplifies through-hole assembly and field replacement.

Applications

Industrial Control Systems
Used for maintaining system configuration data and event logs with accurate timestamps even during total power loss.
Legacy Computing Maintenance
Ideal for replacing expired RTC modules in vintage workstations and arcade hardware that require 32KB of parallel NVRAM.
Embedded Data Logging
Provides reliable time-stamped data storage for remote monitoring equipment operating on 5V supply rails.

Key Specifications

Type Clock/Calendar
Features Leap Year
Interface Parallel
Date Format YY-MM-DD-dd
Time Format HH:MM:SS (24 hr)
Mounting Type Through Hole
Package / Case 28-DIP Module (0.600", 15.24mm)
Voltage - Supply 4.75V ~ 5.5V
Operating Temperature 0degC ~ 70degC
Supplier Device Package 28-PCDIP, CAPHAT
Current - Timekeeping (Max) 2mA @ 4.75V ~ 5.5V

Getting Started

To integrate this part, ensure your system provides a stable 4.75V to 5.5V supply. Interfacing is handled via a standard parallel asynchronous SRAM protocol; simply map the 32KB address space into your MCU or CPU memory map and access the top 8 bytes to read or set the RTC registers.

Also Consider

M48T35Y-70PC1 STMicroelectronics - A 10-percent voltage tolerance version suitable for systems where the supply may drop to 4.5V.
DS12885+ Maxim Integrated / Analog Devices - A popular alternative RTC for parallel bus architectures, though it requires an external battery and crystal.