25LC256-E/SN

Overview

The Microchip Technology 25LC256-E/SN is a 256 Kbit (32,768 x 8-bit) Serial Electrically Erasable PROM. It operates within a supply voltage range of 2.5V to 5.5V and supports a maximum clock frequency of 10 MHz via an SPI-compatible serial bus. The device features a 64-byte page size and self-timed erase/write cycles with a maximum duration of 5 ms. It is housed in an 8-lead SOIC package and supports an extended industrial temperature range from -40°C to +125°C.

Feature Summary

• Supports block write protection allowing configuration to protect none, one-quarter, one-half, or the entire memory array.
• Includes built-in power-on/off data protection circuitry and a dedicated write-protect pin for hardware security.
• Features a hold input that allows suspension of serial communication without resetting the sequence.

Applications

• Data storage in microcontroller systems requiring non-volatile retention
• Configuration parameter storage in embedded devices
• Calibration data logging in industrial instrumentation

Procurement Notes

Verify the specific suffix 'E' confirms the extended temperature rating (-40°C to +125°C) and 'SN' indicates the 8-lead SOIC package. Confirm RoHS compliance status as required by your manufacturing standards. Ensure the ordering code matches the exact voltage and speed specifications needed for your target application environment.

Selection Notes

Select this component when an SPI interface is preferred over I2C for system architecture compatibility. The 25LC256-E variant is suitable for applications requiring operation at elevated temperatures up to 125°C. Consider the 64-byte page write capability for efficient data throughput requirements compared to byte-write-only alternatives.

Part Context

This part belongs to the 25XX256 family of Serial EEPROMs manufactured by Microchip Technology. It shares functional similarities with the 25AA256 but differs in minimum operating voltage. The device utilizes standard SPI protocols for communication, making it compatible with a wide range of host controllers supporting this bus standard.

Replacement Considerations

Direct replacements include other variants within the 25LC256 series such as 25LC256-I/SN for industrial temperature ranges. Cross-reference package types like TSSOP or DFN if footprint changes are permissible. Verify voltage tolerances when substituting with lower-voltage counterparts like the 25AA256 series.

FAQ

How does the HOLD pin function during serial communication?

The HOLD pin suspends transmission to the device while in the middle of a serial sequence. When pulled low, the SI, SCK, and SO pins enter a high-impedance state, ignoring transitions until the HOLD pin is released.

What is the mechanism for preventing inadvertent writes?

The device uses a write enable latch that must be set via the WREN instruction before any write operation can complete. This latch resets automatically after power-up, successful write execution, or upon receiving a WRDI instruction.