48L256T-I/SN

Overview

The Microchip Technology 48L256T-I/SN is a 256-Kbit Serial EERAM featuring an SRAM core with hidden EEPROM backup. It operates on a high-speed SPI interface supporting up to 66 MHz clock frequency within a 2.7V to 3.6V supply range. The device provides unlimited read/write cycles for the SRAM array, organized as 32K x 8 bits, while ensuring data retention through automatic cell-for-cell transfers during power disruptions. It includes a 16-bit nonvolatile user space and supports industrial temperature ranges from -40°C to +85°C in an 8-lead SOIC package.

Feature Summary

• Combines high-speed symmetric SRAM access with hidden nonvolatile EEPROM backup for seamless data preservation.
• Supports high-frequency SPI communication up to 66 MHz with Schmitt trigger inputs for noise suppression.
• Features automatic data transfer to EEPROM upon power loss using external capacitor energy storage.
• Includes dedicated 16-bit nonvolatile user space and configurable block write protection levels.

Applications

• Data logging systems requiring frequent updates with guaranteed retention
• Configuration storage in embedded controllers needing fast access and nonvolatility
• Industrial control applications operating under variable power conditions
• Real-time clock or state memory backup in battery-backed systems

Procurement Notes

Verify the specific suffix 'I/SN' corresponds to the Industrial temperature grade (-40°C to +85°C) and 8-Lead SOIC package. Confirm that the design includes the required VCAP pin connection with a suitable external capacitor (typically 33 μF) for proper AutoStore functionality. Ensure the system voltage remains strictly within the 2.7V to 3.6V operational range to prevent malfunction.

Selection Notes

Select this component when both high-speed random access and nonvolatile data retention are required without complex software management of backup cycles. It is suitable for designs where standard SRAM would lose data on power failure but Flash/EEPROM write speeds are insufficient. Verify compatibility with SPI Mode 0 or 3 masters and ensure the power supply architecture can support the transient currents during store operations.

Part Context

The 48L256 belongs to Microchip's Serial EERAM family, bridging the gap between volatile SRAM and nonvolatile EEPROM. Unlike traditional serial EEPROMs, it offers unlimited write endurance by storing data permanently only during specific events. This model specifically utilizes the SPI interface for high-speed communication, distinguishing it from I2C-based counterparts in the same capacity class.

Replacement Considerations

Direct replacements must match the 256-Kbit capacity, SPI interface, and 8-lead SOIC package. Check if alternative devices support the same 2.7V-3.6V voltage range and industrial temperature grade. Note that functional equivalents may differ in maximum clock speed or require different VCAP capacitor values for reliable operation.