25AA640XT-I/ST

Memory IC Overview

The Microchip Technology 25AA640XT-I/ST is a 64 Kbit (8192 x 8 bit) Serial Electrically Erasable PROM. It features an SPI-compatible serial bus interface with SCK, SI, SO, and CS signals. The device supports a maximum clock frequency of 1 MHz at VCC = 1.8V to 5.5V. Operating voltage ranges from 1.8V to 5.5V for Industrial temperature grades (-40°C to +85°C). Key electrical characteristics include typical standby current of 500 nA, read current of 500 μA, and write current of 3 mA. Data retention exceeds 200 years.

Memory IC Feature Summary

• Supports block write protection allowing selection of none, 1/4, 1/2, or all array segments.
• Includes built-in power on/off data protection circuitry and a write enable latch.
• Features a Hold pin to pause serial communication without resetting the sequence.

Memory IC Applications

• Microcontroller system data storage
• Configuration parameter storage
• Calibration data retention

Memory IC Procurement Notes

Verify the specific ordering suffix 'XT' against official Microchip documentation to confirm package type and tape-and-reel specifications. Ensure the Industrial temperature grade (-40°C to +85°C) matches application requirements. Confirm that the 1 MHz maximum clock speed at 1.8V-5.5V is sufficient for the target system timing constraints.

Memory IC Selection Notes

Select this component for applications requiring non-volatile memory with low-power CMOS technology. The 8-pin TSSOP package is suitable for surface mount designs. Consider the 32-byte page write capability for efficient data programming. Verify compatibility with the host microcontroller's SPI interface modes.

Memory IC Part Context

This part belongs to the 25AA640/25LC640 family of 64 Kbit Serial EEPROMs. The datasheet DS21223H indicates these devices are not recommended for new designs; users are advised to use the 25AA640A or 25LC640A variants instead. The 'I' suffix denotes the Industrial temperature range.

Memory IC Replacement Considerations

Officially documented substitutes include the 25AA640A and 25LC640A series. Verify pinout and electrical specifications before substitution.