DS1321+

Controllers Overview

The DS1321+ is a flexible nonvolatile memory controller with an integrated lithium battery monitor. It converts CMOS SRAM into nonvolatile memory by automatically switching to a backup battery supply when the main VCCI power fails. The device supports up to four SRAMs in three configurable bank modes and provides unconditionally write-protected operation during power outages. It monitors battery voltage to signal impending failure via an open-drain output. The component operates within a -40°C to +85°C industrial temperature range and accepts a 4.75V to 5.5V supply.

Controllers Feature Summary

• Converts standard CMOS SRAM into nonvolatile memory through automatic power switching and write protection
• Monitors lithium battery capacity and signals low-battery conditions via an active-low warning output
• Configurable memory organization supporting multiple SRAM banks for flexible system integration
• Provides processor reset signals during power failures and holds the system in reset during power-up

Controllers Applications

• Battery-backed nonvolatile memory systems requiring data retention during power loss
• Industrial control systems needing reliable power-fail detection and processor reset management
• Embedded applications utilizing lithium coin cells for long-term data preservation

Controllers Procurement Notes

Verify the specific package variant required, as the base model number corresponds to the 16-pin PDIP configuration. Confirm RoHS compliance status indicated by the plus suffix. Ensure the design accommodates the necessary external pull-up resistors for the open-drain Battery Warning and Reset outputs. Check for availability of alternative packages such as SO or TSSOP if surface-mount assembly is preferred.

Controllers Selection Notes

Select this controller when designing systems that require seamless transition between main power and battery backup for SRAM arrays. Consider the available memory configurations based on the number of SRAM chips used. Evaluate the need for battery monitoring features versus simple backup functionality. Verify that the operating voltage range matches the system's power supply specifications and that the thermal characteristics suit the intended environment.

Controllers Part Context

The DS1321 belongs to a family of flexible nonvolatile controllers designed to manage SRAM backup and battery health. Variants include the DS1321S+ in a 16-pin SO package and the DS1321E+ in a 20-pin TSSOP package. All variants share the same core functionality but differ in physical footprint and pinout compatibility. The series addresses the challenge of maintaining data integrity in volatile memory without complex software overhead.

Controllers Replacement Considerations

Direct substitutes include other models within the DS1321 family with different package types, such as the DS1321S+ or DS1321E+, provided the board layout supports the respective pin configurations.