25LC640T-I/SNG

Overview

The Microchip Technology 25LC640T-I/SN is a 64 Kbit (8192 x 8 bit) Serial Electrically Erasable PROM. It utilizes an SPI-compatible serial bus with SCK, SI, SO, and CS signals for communication. The device supports a maximum clock frequency of 2 MHz at VCC levels between 2.5V and 5.5V. It operates within an industrial temperature range of -40°C to +85°C. The component is housed in an 8-pin SOIC package.

Feature Summary

• Supports sequential read operations with automatic address pointer incrementation across the memory array.
• Includes built-in write protection mechanisms such as a write enable latch and power-on data protection circuitry.
• Features a Hold pin that allows suspension of serial transmission without resetting the sequence.

Applications

• Data storage for microcontroller systems via SPI interface
• Configuration parameter persistence
• Calibration value retention

Procurement Notes

Verify the specific suffix 'T' indicates tape and reel packaging when sourcing this part number. Confirm the 'I' designation matches the required industrial temperature range of -40°C to +85°C. Ensure the voltage supply aligns with the 2.5V to 5.5V operational limits specified for the 25LC640 series.

Selection Notes

Select this component for applications requiring non-volatile storage accessed through standard SPI ports. Consider the 32-byte page write capability for efficient data updates. Evaluate the block write protection features if specific memory segments require hardware-level security against inadvertent writes.

Part Context

This device belongs to the 25XX640 family of serial EEPROMs from Microchip Technology. It shares functional similarities with the 25AA640 but differs in operating voltage requirements. The datasheet notes it is not recommended for new designs, suggesting the use of the updated 25LC640A series instead.

Replacement Considerations

Public confirmed substitute: 25LC640AT-I/SN

FAQ

How does the Hold function affect serial communication?

Pulling the HOLD pin low pauses transmission while keeping the device selected. Transitions on SI, SCK, and SO are ignored during this state, allowing the host to service higher priority interrupts before resuming communication.

What is the purpose of the Write Enable Latch?

The write enable latch must be set by issuing the WREN instruction before any write operation can be completed internally. It resets automatically after power-up or upon completion of a write cycle.