DS1251Y-150

Overview

The DS1251Y-150 is a parallel interface Real-Time Clock (RTC) and non-volatile static RAM device manufactured by Analog Devices Inc./Maxim Integrated. It integrates a 512KB NV SRAM array with a phantom clock mechanism for continuous timekeeping without external backup batteries. The component supports both 3V and 5V logic supply ranges, operating between 2.97V to 3.63V or 4.5V to 5.5V. It features BCD-coded date and time registers, leap year compensation, and automatic write protection. The device is housed in a 32-EDIP through-hole package.

Feature Summary

• Integrated 512KB Non-Volatile Static RAM with phantom clock technology
• Dual voltage operation: 3V (2.97V–3.63V) and 5V (4.5V–5.5V)
• Parallel interface with BCD date/time formats and leap year correction
• Automatic power-fail detection and write-protect control

Applications

• Industrial systems requiring persistent time and data storage
• Telecommunications equipment with main power interruptions
• Data logging devices needing high-capacity non-volatile memory
• Embedded controllers utilizing phantom clock functionality

Procurement Notes

Verify the specific suffix 'Y' against official datasheets to confirm pinout and voltage compatibility. Confirm RoHS compliance status as '+', if required, differs from the base part number. Check for obsolescence notices from Analog Devices regarding this specific variant.

Selection Notes

Select this component when a large block of non-volatile memory is required alongside real-time clocking functions. The phantom clock feature eliminates the need for battery maintenance. Ensure the host system supports parallel bus interfacing and matches the 3V or 5V supply rail requirements.

Part Context

This part belongs to the Maxim Integrated DS1251 series of phantom clock RTCs. Unlike standard RTCs that use lithium batteries, these devices utilize a small internal capacitor charged during main power availability to maintain timekeeping. This design reduces long-term maintenance costs associated with battery replacement.

Replacement Considerations

Direct replacements include other DS1251 variants such as DS1251W-120IND+ or DS1251WP-120+, provided the package type (DIP vs. PowerCap) and speed grade are compatible with the PCB layout.