DS1556P-70+

Real Time Clock Overview

The DS1556P-70+ is a nonvolatile, Y2K-compliant timekeeping RAM device manufactured by Analog Devices Inc./Maxim Integrated. It integrates a real-time clock/calendar (RTC), 128k x 8 static RAM, crystal oscillator, power-fail control circuit, and lithium energy source within a single component. The device utilizes a parallel interface with 17 address lines and an 8-bit data bus. It operates at a nominal voltage of 5.0V and supports a commercial temperature range of 0°C to +70°C. The RTC provides century, year, month, date, day, hours, minutes, and seconds in BCD format with automatic leap-year compensation valid through the year 2100.

Real Time Clock Feature Summary

• Integrated NV SRAM, Real-Time Clock, Crystal, Power-Fail Control Circuit, and Lithium Energy Source
• Y2K Compliant with Century Byte Register and Automatic Leap-Year Compensation Valid Up to Year 2100
• Programmable Watchdog Timer and RTC Alarm with Interrupt Output
• Precision Power-On Reset and Battery Voltage-Level Indicator Flag

Real Time Clock Applications

• Systems requiring precise timekeeping and nonvolatile data storage without external components
• Industrial equipment needing battery-backed memory and clock functions
• Embedded controllers utilizing watchdog timer for system stability monitoring

Real Time Clock Procurement Notes

Verify that the separate DS9034PCX or DS9034I-PCX PowerCap module is ordered, as it is required for the DS1556P-70+ package. Confirm the specific temperature grade (+70°C vs -40°C to +85°C) matches the application requirements. Ensure the system design accommodates the 34-pin PowerCap module board dimensions and mounting constraints.

Real Time Clock Selection Notes

Select the DS1556P-70+ when a 5.0V supply is available and a commercial temperature range (0°C to +70°C) is sufficient. Choose this part over the DIP version if surface-mount assembly is preferred, provided the separate PowerCap module can be mounted post-reflow. Verify compatibility with the 34-pin PowerCap module board layout.

Real Time Clock Part Context

The DS1556P-70+ belongs to the DS1556 family of nonvolatile timekeeping RAMs. It shares core functionality with the DS1556-70+ but differs in packaging. While the DS1556-70+ uses a 32-pin EDIP module integrating all components, the DS1556P-70+ uses a 34-pin PowerCap module board that requires a separate PowerCap unit containing the crystal and battery.

Real Time Clock Replacement Considerations

Public confirmed substitute part numbers are not available in the provided documentation.