DS1321S+

Overview

The DS1321S+ is a flexible nonvolatile controller with a lithium battery monitor, designed to convert CMOS SRAMs into nonvolatile memory. It operates within an industrial temperature range of -40°C to +85°C and accepts a supply voltage between 4.75V and 5.5V. The device supports up to four SRAMs in three configurable bank modes. It features automatic power-fail detection, write protection, and processor reset generation. Battery monitoring occurs periodically every 24 hours.

Feature Summary

• Converts standard CMOS SRAMs into nonvolatile memory by managing power switching and write protection during supply failures.
• Monitors lithium backup battery capacity by performing periodic loaded-voltage measurements to provide advance warning of impending failure.
• Configurable memory organization allows support for one, two, or four SRAM banks via the MODE pin.

Applications

• Battery backup systems for volatile memory modules
• Processor-based systems requiring power-fail detection and reset signals
• Industrial equipment requiring nonvolatile data retention

Procurement Notes

Verify component authenticity through authorized distributors. Confirm RoHS compliance status as indicated by the '+' suffix. Ensure the specific package variant matches design requirements. Check current availability status as supply may be limited. Validate datasheet revision against manufacturing date codes.

Selection Notes

Select this controller when converting multiple CMOS SRAMs to nonvolatile storage is required. Choose based on the number of SRAMs needed: Mode 0 for four single-bank units, Mode 1 for two dual-bank units, or Mode 2 for one quad-bank unit. Verify TOL pin configuration for desired power-fail tolerance levels. Ensure system power-up sequences align with the reset hold time requirements.

Part Context

The DS1321S+ belongs to the DS1321 family of flexible nonvolatile controllers manufactured by Analog Devices Inc./Maxim Integrated. This series includes variants such as the DS1321+ (PDIP) and DS1321E+ (TSSOP). The S+ suffix specifically denotes the 16-pin SO package with lead-free/RoHS-compliant construction.

Replacement Considerations

DS1321+