DS1251W-120+

Overview

The DS1251W-120+ is a nonvolatile RAM (NVSRAM) real-time clock module manufactured by Analog Devices Inc./Maxim Integrated. It integrates 512K x 8 bits of static RAM with a phantom clock for timekeeping, including hundredths of seconds, minutes, hours, days, dates, months, and years. The device operates on a single 3.3V supply within a 3.3V ±10% range and supports an operating temperature from 0°C to +70°C. It features automatic leap year compensation valid up to the year 2100 and maintains data retention for over 10 years using an embedded lithium energy cell. The component utilizes a parallel interface and is housed in a 32-pin EDIP package.

Feature Summary

• Integrates 512K x 8 NV SRAM with a phantom clock for calendar and timekeeping functions
• Includes automatic leap year compensation valid through the year 2100
• Features an embedded lithium energy source that disconnects electrically until initial power application
• Provides over 10 years of data retention in the absence of VCC power

Applications

• Systems requiring persistent timekeeping and volatile RAM replacement
• Industrial equipment needing reliable date and time tracking
• Embedded devices utilizing parallel memory interfaces

Procurement Notes

Verify the specific ordering suffix against the manufacturer's current documentation to confirm lead time and availability status. Confirm that the required PowerCap or crystal components are ordered separately if utilizing the PowerCap variant, though this specific model is a DIP module. Ensure compliance with RoHS standards as indicated by the '+' suffix in the part number.

Selection Notes

Select the DS1251W-120+ when a 3.3V supply voltage is available and the commercial temperature range of 0°C to +70°C meets system requirements. This model is suitable for through-hole mounting applications requiring a 32-pin EDIP footprint. For industrial temperature ranges (-40°C to +85°C), consider the DS1251W-120IND+ variant instead.

Part Context

The DS1251W-120+ belongs to the DS1251 series of 4096K NV SRAM modules with phantom clocks. It is upward compatible with the DS1248 series and shares pinouts with other densities in the DS124xP family. The device replaces traditional volatile static RAM or EEPROM solutions by combining memory storage with autonomous timekeeping capabilities in a single DIP module.

Replacement Considerations

The DS1251W-120+ is upward compatible with the DS1248. For industrial temperature operation, the DS1251W-120IND+ serves as the direct equivalent with extended thermal specifications.