DS1553-70

Real Time Clock Overview

The DS1553-70 is a Year-2000-compliant real-time clock/calendar integrated with 64kB nonvolatile static RAM. It features a byte-wide parallel interface, automatic leap year compensation, and BCD-coded timekeeping registers. The device includes an internal lithium battery source for over 10 years of data retention without power. Key functions include a programmable watchdog timer, RTC alarm, power-on reset, and battery voltage monitoring. Operating at 5V or 3.3V, it provides precise timing accuracy within ±1 minute per month at +25°C.

Real Time Clock Feature Summary

• Integrated 64kB NV SRAM with identical access to RTC registers
• Year-2000 compliant with automatic leap year correction up to 2100
• Built-in lithium energy source providing >10 years backup life
• Programmable watchdog timer and RTC alarm with interrupt output

Real Time Clock Applications

• Industrial control systems requiring precise timekeeping
• Data logging equipment needing nonvolatile storage
• Embedded systems with watchdog timer requirements
• Battery-powered devices with low standby current needs

Real Time Clock Procurement Notes

Verify the specific suffix (e.g., -85, -100) against the required voltage and package type. Confirm RoHS compliance status as indicated by the '+' symbol in ordering information. Check for availability of separate PowerCap modules if using the 34-pin variant. Ensure compatibility with existing system voltage levels before procurement.

Real Time Clock Selection Notes

Select based on operating voltage: 5V for standard logic levels or 3.3V for lower power applications. Choose between 28-pin EDIP (integrated crystal/battery) or 34-pin PowerCap (separate module) packages. Consider temperature range requirements; commercial grade covers 0°C to +70°C. Verify interface timing constraints match system bus speeds.

Real Time Clock Part Context

The DS1553 series belongs to Maxim Integrated's family of nonvolatile timekeeping RAM devices. It combines RTC functionality with substantial SRAM capacity in a single package. The device simplifies system design by integrating the crystal and battery source, reducing component count and board space requirements compared to discrete solutions.

Real Time Clock Replacement Considerations

Direct replacements must match the 64kB NV SRAM capacity and RTC functionality. Verify pin compatibility for 28-pin DIP or 34-pin PowerCap packages. Ensure equivalent voltage operation (5V or 3.3V) and temperature range. Check if alternative parts require external crystals or batteries, which may impact board layout.