25LC256T-E/ST EEPROM Memory IC Equivalent & Substitute Parts

Part Overview

The 25LC256T-E/ST is a 256Kbit Serial Peripheral Interface (SPI) EEPROM memory IC manufactured by Microchip Technology in an 8-TSSOP surface mount package. This non-volatile memory device operates at 10 MHz clock frequency with a 5ms write cycle time and supports supply voltages from 2.5V to 5.5V across an operating temperature range of -40°C to 125°C. The part is ROHS3 compliant and carries an MSL rating of 1 (Unlimited). Equivalent and substitute parts are identified based on matching memory capacity, interface protocol, package type, and electrical operating parameters to ensure functional interchangeability in circuit applications.

Key Parameters

Parameter	Value
Memory Size	256Kbit
Memory Organization	32K x 8
Memory Interface	SPI
Clock Frequency	10 MHz
Write Cycle Time	5ms
Voltage Supply Range	2.5V ~ 5.5V
Operating Temperature	-40°C ~ 125°C
Package Type	8-TSSOP (0.173", 4.40mm Width)
Mounting Type	Surface Mount
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitute parts for the 25LC256T-E/ST are grouped based on the following substitution criteria:

Primary Matching Parameters:

Memory capacity: 256Kbit
Memory organization: 32K x 8
Interface protocol: SPI
Package: 8-TSSOP surface mount
RoHS compliance: ROHS3

Secondary Compatibility Factors:

Clock frequency: 10 MHz or higher (backward compatible)
Supply voltage range: Must encompass or exceed 2.5V ~ 5.5V
Operating temperature: Must support -40°C minimum and 125°C maximum, or equivalent industrial range
Write cycle time: 4ms or 5ms (functionally equivalent)

Substitutes are divided into two categories: direct equivalents (identical specifications) and enhanced alternatives (higher clock frequency or extended temperature range). All substitute parts maintain identical pinout, package dimensions, and SPI protocol compatibility.

Parameter Comparison

Part Number	Manufacturer	Memory Size	Clock Frequency	Supply Voltage	Operating Temperature	Write Cycle Time	Package	Inventory
25LC256T-E/ST	Microchip Technology	256Kbit	10 MHz	2.5V ~ 5.5V	-40°C ~ 125°C	5ms	8-TSSOP	3570 Pcs
25LC256-E/ST	Microchip Technology	256Kbit	10 MHz	2.5V ~ 5.5V	-40°C ~ 125°C	5ms	8-TSSOP	2300 Pcs
AT25256B-XHL-B	Microchip Technology	256Kbit	20 MHz	1.8V ~ 5.5V	-40°C ~ 85°C	5ms	8-TSSOP	2159 Pcs
CAT25256YI-GT3	onsemi	256Kbit	20 MHz	1.8V ~ 5.5V	-40°C ~ 85°C	5ms	8-TSSOP	1884 Pcs
CAV25256YE-GT3	onsemi	256Kbit	10 MHz	2.5V ~ 5.5V	-40°C ~ 125°C	5ms	8-TSSOP	3301 Pcs
M95256-DFDW6TP	STMicroelectronics	256Kbit	20 MHz	1.7V ~ 5.5V	-40°C ~ 85°C	5ms	8-TSSOP	2863 Pcs
M95256-DRDW3TP/K	STMicroelectronics	256Kbit	20 MHz	1.8V ~ 5.5V	-40°C ~ 125°C	4ms	8-TSSOP	2100 Pcs
M95256-DWDW4TP/K	STMicroelectronics	256Kbit	10 MHz	2.5V ~ 5.5V	-40°C ~ 145°C	4ms	8-TSSOP	4180 Pcs
M95256-RDW6TP	STMicroelectronics	256Kbit	20 MHz	1.8V ~ 5.5V	-40°C ~ 85°C	5ms	8-TSSOP	20598 Pcs
M95256-WDW6TP	STMicroelectronics	256Kbit	20 MHz	2.5V ~ 5.5V	-40°C ~ 85°C	5ms	8-TSSOP	31000 Pcs

Engineering Selection Recommendations

Direct Equivalent (Identical Specifications): The 25LC256-E/ST from Microchip Technology is a direct equivalent with matching clock frequency (10 MHz), supply voltage range (2.5V ~ 5.5V), operating temperature (-40°C ~ 125°C), and write cycle time (5ms). This part maintains full functional compatibility and is suitable for one-to-one replacement.

Enhanced Alternatives (Higher Clock Frequency): Parts with 20 MHz clock frequency (AT25256B-XHL-B, CAT25256YI-GT3, M95256-DFDW6TP, M95256-DRDW3TP/K, M95256-RDW6TP, M95256-WDW6TP) provide increased data transfer rates while maintaining backward compatibility with 10 MHz SPI interfaces. These are suitable for applications requiring higher performance without circuit redesign.

Extended Temperature Range: The M95256-DWDW4TP/K supports an extended operating temperature range of -40°C to 145°C, exceeding the original specification. This part carries AEC-Q100 automotive qualification and is suitable for high-temperature industrial applications.

Automotive Grade Options: CAV25256YE-GT3, M95256-DRDW3TP/K, and M95256-DWDW4TP/K carry AEC-Q100 qualification for automotive applications. These parts are suitable for automotive-grade circuit implementations.

Supply Voltage Considerations: Parts with lower minimum supply voltage (1.7V or 1.8V) provide extended low-voltage operation capability. M95256-DFDW6TP supports 1.7V minimum, while AT25256B-XHL-B, CAT25256YI-GT3, M95256-DRDW3TP/K, M95256-RDW6TP support 1.8V minimum. The original 25LC256T-E/ST requires 2.5V minimum.

Frequently Asked Questions (FAQ)

Q: Can I use a 20 MHz substitute in place of the 10 MHz 25LC256T-E/ST? A: Yes. Higher clock frequency parts are backward compatible with 10 MHz SPI interfaces. The SPI bus will operate at the lower frequency determined by the master controller, ensuring functional compatibility.

Q: What is the difference between the 25LC256T-E/ST and 25LC256-E/ST? A: Both parts are manufactured by Microchip Technology with identical electrical specifications (256Kbit, 10 MHz, 2.5V ~ 5.5V, -40°C ~ 125°C). The primary difference is packaging: 25LC256T-E/ST uses Tape & Reel (TR) packaging, while 25LC256-E/ST uses Tube packaging. Electrical performance is identical.

Q: Are all substitute parts pin-compatible with the 25LC256T-E/ST? A: Yes. All listed substitute parts use the 8-TSSOP package with identical pinout and SPI protocol. Physical and electrical pin compatibility is maintained across all substitutes.

Q: Which substitute offers the best low-voltage operation? A: The M95256-DFDW6TP supports the lowest minimum supply voltage at 1.7V, followed by AT25256B-XHL-B, CAT25256YI-GT3, M95256-DRDW3TP/K, and M95256-RDW6TP at 1.8V minimum. The original 25LC256T-E/ST requires 2.5V minimum.

Q: Can I use an automotive-grade part in a non-automotive application? A: Yes. Automotive-grade parts (CAV25256YE-GT3, M95256-DRDW3TP/K, M95256-DWDW4TP/K) meet higher reliability and qualification standards and are suitable for any application requiring equivalent or superior performance specifications.

Q: What is the write cycle time difference between 4ms and 5ms parts? A: Write cycle time represents the duration required to complete a single page write operation. Parts with 4ms write cycle time (M95256-DRDW3TP/K, M95256-DWDW4TP/K) complete write operations faster than 5ms parts. This difference is functionally transparent in most applications but provides performance advantage in write-intensive operations.

Q: Which substitute has the highest inventory availability? A: The M95256-WDW6TP from STMicroelectronics has the highest inventory at 31,000 pieces, followed by M95256-RDW6TP at 20,598 pieces. Both parts support 20 MHz clock frequency and 2.5V ~ 5.5V supply voltage range.

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