25LC256-E/ST16KVAO

Overview

The Microchip Technology 25LC256-E/ST16KVAO is a 256 Kbit (32,768 x 8-bit) Serial Electrically Erasable PROM. It operates within a voltage range of 1.8V 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 offers high reliability with 1,000,000 erase/write cycle endurance and data retention exceeding 200 years. The component is housed in an 8-lead TSSOP package and supports an extended 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 write enable latch to prevent inadvertent writes.
• Features a hold pin that allows suspension of serial communication without resetting the sequence.

Applications

• Data storage for microcontroller systems requiring non-volatile memory
• Configuration parameter storage in industrial control devices
• Calibration data retention in sensor interfaces

Procurement Notes

Verify the specific suffix '16KVAO' against official Microchip documentation to confirm exact marking and packaging details. Ensure the selected variant matches the required temperature grade and package type for your design constraints.

Selection Notes

Select this component when an SPI interface is preferred over I2C for EEPROM applications. The extended temperature range (-40°C to +125°C) makes it suitable for harsh environments. Consider the 64-byte page write limit when designing firmware to optimize write performance.

Part Context

This part belongs to the 25LC256 family of 256 Kbit Serial EEPROMs manufactured by Microchip Technology. The family includes variants with different temperature grades (Industrial and Extended) and package options such as PDIP, SOIC, DFN, and TSSOP. All variants share the same core electrical characteristics and instruction set.

Replacement Considerations

Direct replacements include other 25LC256 variants from Microchip with compatible packages and voltage ranges, such as 25LC256-I/ST or 25LC256-E/SN. Verify pinout compatibility and ensure the substitute meets the required operating temperature and voltage specifications.

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 without resetting the sequence. It must be held low while SCK is low to pause communication, tri-stating the SO line until released.

What is the purpose of the WPEN bit in the STATUS register?

The WPEN bit enables or disables the hardware write-protect function of the WP pin. When WPEN is high and the WP pin is low, writing to the nonvolatile bits in the STATUS register is disabled.