DS1251Y-70+

Overview

The DS1251Y-70+ is a nonvolatile SRAM integrated with a phantom real-time clock, manufactured by Analog Devices Inc./Maxim Integrated. It features 4096K (512K x 8) of static RAM and maintains timekeeping data via an embedded lithium energy cell. The device operates on a single 5V supply within the 4.5V to 5.5V range, consuming up to 85mA during active operation. It utilizes a parallel interface with a 70ns access time and is housed in a 32-pin EDIP module designed for through-hole mounting. The component supports automatic leap year compensation and provides over 10 years of data retention without power.

Feature Summary

• Integrates 512K x 8 NV SRAM with a phantom real-time clock for simultaneous data storage and timekeeping.
• Features automatic leap year compensation valid up to the year 2100 and supports 12/24-hour formats.
• Includes an embedded lithium energy source that automatically switches to battery backup when VCC drops below the power-fail threshold.
• Provides transparent write protection to prevent data corruption during power loss events.

Applications

• Industrial control systems requiring persistent memory and accurate time tracking.
• Data logging equipment needing reliable nonvolatile storage for sensor readings.
• Telecommunications infrastructure maintaining system logs and timestamps.
• Medical devices requiring precise event recording and data retention.

Procurement Notes

Verify the specific suffix 'Y-70+' corresponds to the 5V operating voltage and commercial temperature range (0°C to +70°C). Confirm the package type matches the required 32-pin EDIP form factor for through-hole assembly. Ensure the design accounts for the separate ordering of PowerCap modules if surface-mount variants are considered instead.

Selection Notes

Select this component when a combined NVRAM and RTC solution is preferred over discrete parts. The 70ns speed suits standard microprocessor buses. Verify compatibility with the host system's address decoding logic, as the phantom clock requires a specific 64-bit pattern recognition sequence for register access.

Part Context

This part belongs to the DS124x/DS125x family of NVSRAMs with phantom clocks. It is upward compatible with the DS1248 series. The 'Y' designation indicates the 5V version, while 'IND' would denote industrial temperature grades. It serves as a drop-in replacement for volatile SRAM or EEPROM in legacy designs requiring time-stamping capabilities.

Replacement Considerations

Public confirmed substitute part numbers: None listed in verified documentation.