25LC640/WF

Overview

The Microchip Technology 25LC640/WF is a 64 Kbit (8192 x 8 bit) Serial Electrically Erasable PROM. It utilizes a standard SPI-compatible serial bus interface requiring SCK, SI, SO, and CS signals. The device supports a maximum clock frequency of 3 MHz at VCC levels between 4.5V and 5.5V. It operates within an industrial temperature range of -40°C to +85°C. Key electrical characteristics include a typical standby current of 500 nA and self-timed erase/write cycles with a maximum duration of 5 ms.

Feature Summary

• Supports sequential read operations with automatic address pointer incrementation across the memory array.
• Includes built-in write protection mechanisms featuring power-on/off data protection circuitry and a dedicated write-protect pin.
• Offers block write protection capabilities allowing users to protect none, one-quarter, one-half, or all segments of the memory array.

Applications

• Data storage for microcontroller systems via direct SPI port interfacing
• Configuration parameter retention in embedded devices
• Calibration data logging in industrial instrumentation

Procurement Notes

Verify that the specific ordering suffix corresponds to the wafer form factor rather than standard packaged units. Confirm voltage requirements align with the 4.5V to 5.5V operational range for optimal performance. Ensure compatibility with existing SPI bus protocols before integration into final designs.

Selection Notes

Select this component when a 64 Kbit non-volatile memory solution is required for industrial applications. It is suitable for designs needing hardware write protection and low standby power consumption. Verify that the system voltage supports the specified operating range and that the SPI interface timing meets the device's setup and hold requirements.

Part Context

This part belongs to the 25AA640/25LC640 family of 64 Kbit Serial EEPROMs manufactured by Microchip Technology. The datasheet DS21223H indicates that these devices are not recommended for new designs; customers are advised to use the updated 25AA640A or 25LC640A series instead.

Replacement Considerations

Public confirmed substitute part numbers: 25LC640A-I/P, 25LC640A-I/SN, 25LC640A-I/ST.