24LC256T-E/ST EEPROM Memory IC Equivalent & Substitute Parts

Part Overview

The 24LC256T-E/ST is a 256Kbit I2C EEPROM memory IC manufactured by Microchip Technology, supplied in Cut Tape (CT) & Digi-Reel® packaging. This non-volatile memory device operates at 400 kHz I2C clock frequency with 900 ns access time and supports a supply voltage range of 2.5V to 5.5V across an operating temperature range of -40°C to 125°C. The device is ROHS3 compliant and actively produced. 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	24LC256T-E/ST
Memory Size	256Kbit
Memory Organization	32K x 8
Memory Interface	I2C
Clock Frequency	400 kHz
Access Time	900 ns
Write Cycle Time	5 ms
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 24LC256T-E/ST are qualified based on the following critical parameters:

Memory capacity of 256Kbit with 32K x 8 organization
I2C serial interface protocol
8-TSSOP surface mount package (0.173", 4.40mm Width)
Write cycle time of 5 ms
Supply voltage compatibility within or overlapping the 2.5V to 5.5V range
Operating temperature range supporting at least -40°C to 85°C minimum

Substitutes are grouped into two categories: direct equivalents (identical packaging and specifications) and functional equivalents (same memory capacity and interface with acceptable parameter variations). Clock frequency variations (400 kHz vs. 1 MHz) and access time differences are acceptable provided the I2C interface and memory organization remain constant. Temperature range extensions and automotive-grade qualifications represent enhanced specifications suitable for broader application requirements.

Parameter Comparison

Part Number	Manufacturer	Memory Size	Clock Frequency	Access Time	Voltage Supply	Operating Temperature	Package	Product Status
24LC256T-E/ST	Microchip Technology	256Kbit	400 kHz	900 ns	2.5V ~ 5.5V	-40°C ~ 125°C	8-TSSOP	Active
24LC256-E/ST	Microchip Technology	256Kbit	400 kHz	900 ns	2.5V ~ 5.5V	-40°C ~ 125°C	8-TSSOP	Active
BR24G256FVT-3GE2	Rohm Semiconductor	256Kbit	400 kHz	Not specified	1.6V ~ 5.5V	-40°C ~ 85°C	8-TSSOP-B	Active
CAV24C256YE-GT3	onsemi	256Kbit	1 MHz	400 ns	2.5V ~ 5.5V	-40°C ~ 125°C	8-TSSOP	Active
M24256-BFDW6TP	STMicroelectronics	256Kbit	1 MHz	450 ns	1.7V ~ 5.5V	-40°C ~ 85°C	8-TSSOP	Active
M24256-BRDW6TP	STMicroelectronics	256Kbit	1 MHz	450 ns	1.8V ~ 5.5V	-40°C ~ 85°C	8-TSSOP	Active
M24256-BWDW6TP	STMicroelectronics	256Kbit	1 MHz	450 ns	2.5V ~ 5.5V	-40°C ~ 85°C	8-TSSOP	Not For New Designs
M24256-DFDW6TP	STMicroelectronics	256Kbit	400 kHz	450 ns	1.7V ~ 5.5V	-40°C ~ 85°C	8-TSSOP	Active
M24256-DRDW3TP/K	STMicroelectronics	256Kbit	1 MHz	450 ns	1.8V ~ 5.5V	-40°C ~ 125°C	8-TSSOP	Active
M24256-DRDW8TP/K	STMicroelectronics	256Kbit	1 MHz	450 ns	1.8V ~ 5.5V	-40°C ~ 105°C	8-TSSOP	Active

Engineering Selection Recommendations

Direct Equivalent (Preferred for Drop-In Replacement): The 24LC256-E/ST from Microchip Technology is the direct equivalent, differing only in packaging format (Tube vs. Cut Tape & Digi-Reel®). This part maintains identical electrical specifications and is recommended for applications requiring no design modification.

Functional Equivalents with Extended Temperature Range: The CAV24C256YE-GT3 (onsemi) and M24256-DRDW3TP/K (STMicroelectronics) both support the full -40°C to 125°C operating temperature range matching the 24LC256T-E/ST. The CAV24C256YE-GT3 includes AEC-Q100 automotive qualification. The M24256-DRDW3TP/K also carries AEC-Q100 qualification and is suitable for automotive applications requiring extended temperature performance.

Functional Equivalents with Standard Temperature Range: The M24256-BFDW6TP, M24256-BRDW6TP, M24256-DFDW6TP, and BR24G256FVT-3GE2 operate within -40°C to 85°C, which is acceptable for non-extended-temperature applications. These parts maintain 256Kbit capacity and I2C interface compatibility. The M24256-BWDW6TP is marked "Not For New Designs" and should be avoided in new circuit development.

Voltage Supply Considerations: All substitute parts support the 2.5V to 5.5V supply range of the 24LC256T-E/ST or extend to lower voltages (1.6V to 1.8V minimum). Parts with lower minimum voltage specifications (BR24G256FVT-3GE2 at 1.6V, M24256-BFDW6TP and M24256-DFDW6TP at 1.7V) provide additional design flexibility for low-power applications.

Clock Frequency and Access Time: The 24LC256T-E/ST operates at 400 kHz with 900 ns access time. Substitutes operating at 1 MHz clock frequency with 400-450 ns access time provide improved performance characteristics. The M24256-DFDW6TP maintains the 400 kHz clock frequency for applications requiring exact frequency matching.

Frequently Asked Questions (FAQ)

Q: Can I use a 1 MHz I2C EEPROM as a substitute for the 400 kHz 24LC256T-E/ST? A: Yes. I2C devices operating at higher clock frequencies are backward compatible with lower-frequency applications. A 1 MHz device will operate correctly in a 400 kHz system. The I2C protocol allows devices to operate at the lower bus frequency.

Q: What is the difference between 8-TSSOP and 8-TSSOP-B packages? A: Both are 8-pin thin shrink small outline packages with identical 0.173" width and 4.40mm body dimensions. The "-B" designation indicates a variant from a different manufacturer (Rohm Semiconductor). Pin configuration and footprint compatibility are maintained.

Q: Is the M24256-BWDW6TP suitable for new designs? A: No. This part is marked "Not For New Designs" by STMicroelectronics. While functionally equivalent, it should not be selected for new circuit development. Use M24256-BRDW6TP or M24256-BFDW6TP instead.

Q: Which substitute offers the best temperature range coverage? A: The M24256-DRDW8TP/K supports -40°C to 105°C, and both the CAV24C256YE-GT3 and M24256-DRDW3TP/K support -40°C to 125°C, matching the 24LC256T-E/ST. The M24256-DRDW8TP/K and M24256-DRDW3TP/K include AEC-Q100 automotive qualification.

Q: Are all substitutes ROHS3 compliant? A: Yes. All listed substitute parts are ROHS3 compliant, matching the environmental compliance status of the 24LC256T-E/ST.

Q: What is the significance of the access time difference (900 ns vs. 450 ns)? A: Access time is the delay from address input to data output availability. Faster access times (450 ns) represent improved performance but do not affect functional compatibility. The 24LC256T-E/ST with 900 ns access time will operate correctly in applications designed for faster devices.

Q: Can I substitute based on packaging alone? A: No. Packaging compatibility is necessary but not sufficient. Memory capacity, I2C interface, voltage supply range, and operating temperature must all be verified. The 8-TSSOP package is common across all listed parts, but electrical specifications must match application requirements.

Request Quote (Ships tomorrow)

Part Number

Quantity

Company

Contact Name

E-mail

Message