DS1221SN

Controllers Overview

The DS1221SN is a nonvolatile RAM controller and decoder IC manufactured by Analog Devices Inc./Maxim Integrated. It converts up to four CMOS RAMs into nonvolatile memories using a 16-SOIC package. The device operates with a supply voltage of 4.5V to 5.5V and supports an operating temperature range of 0°C to 70°C. It features automatic data protection during power loss, battery redundancy support, and optional security access prevention.

Controllers Feature Summary

• Converts CMOS RAMs into nonvolatile memories through automatic power-fail detection and battery switching
• Includes a 2-to-4 decoder for selecting one of four connected CMOS RAMs
• Supports redundant batteries with internal isolation switches for reliability
• Offers optional security features to prevent unauthorized memory access

Controllers Applications

• Battery-backup systems for CMOS RAM banks
• Data integrity protection in industrial control environments
• Systems requiring redundant power sources for critical memory storage

Controllers Procurement Notes

Verify the obsolete status of this component before procurement planning. Confirm that the 16-SOIC package matches your PCB footprint requirements. Ensure compatibility with the 4.5V to 5.5V supply voltage range. Check for available replacement options such as the DS1321 if new designs are required.

Controllers Selection Notes

Select this controller when integrating multiple CMOS RAMs into a single nonvolatile memory system. Consider the 16-pin SOIC package for surface mount applications. Evaluate the need for security features based on system access requirements. Verify battery voltage thresholds align with the 2.0V minimum detection level.

Controllers Part Context

The DS1221 series includes variants like the DS1221S and DS1221Y. The SN suffix denotes the 16-SOIC surface mount package variant. This component belongs to the broader family of nonvolatile memory controllers designed for battery-backed SRAM applications.

Controllers Replacement Considerations

The datasheet recommends the DS1321 as a replacement for new designs.