DS1251Y-70

Overview

The DS1251Y-70 is a 4096K nonvolatile SRAM integrated with a phantom real-time clock, manufactured by Analog Devices Inc./Maxim Integrated. It features 512K x 8 memory organization and operates within a 4.5V to 5.5V supply range. The device provides a 70ns access time and supports parallel interface communication via a 32-pin EDIP module package. Designed for through-hole mounting, it includes an embedded lithium energy source that maintains calendar operation and data retention for over 10 years when VCC is absent. The component automatically switches power sources upon detecting out-of-tolerance conditions.

Feature Summary

• Integrates 512K x 8 NV SRAM with a phantom real-time clock supporting hundredths of seconds, minutes, hours, days, dates, months, and years.
• Features automatic leap year compensation valid up to the year 2100 and transparent watch function operation.
• Includes an embedded lithium energy source electrically disconnected until first power application, ensuring full freshness.
• Provides write protection and battery switchover when VCC falls below specified thresholds to prevent data corruption.

Applications

• Systems requiring persistent timekeeping and data storage without external volatile RAM or EEPROM.
• Industrial equipment needing reliable calendar tracking with automatic date adjustments.
• Embedded controllers utilizing phantom clock serial bit stream communication for time register access.

Procurement Notes

Verify the specific suffix 'Y-70' corresponds to the 5.0V operating voltage and commercial temperature range (0°C to +70°C). Confirm the package type is the 32-pin EDIP module, as PowerCap variants exist. Check current availability status, as this component may be subject to limited supply or end-of-life restrictions.

Selection Notes

Select the DS1251Y-70 for applications requiring 5V logic compatibility and through-hole assembly. Ensure the design accommodates the 64-bit pattern recognition sequence required to access the phantom clock registers. Verify that the system can handle the internal pullup on the RST pin and respects the write recovery times during high-speed operations.

Part Context

This part belongs to the DS1251 family of 4096K NV SRAMs with phantom clocks. It is upward compatible with the DS1248 series. The 'Y' suffix indicates the 5V version, while 'W' denotes the 3.3V variant. The '70' specifies the 70ns speed grade. Other packages include the 34-pin PowerCap module for surface mount applications.

Replacement Considerations

Public confirmed substitute part numbers are not available in the provided documentation. Designers should verify pin-for-pin compatibility with existing DS1248 implementations if upgrading from lower density modules.