Equivalent & Substitute Parts for 24AA256T-I/ST

Part Overview

The 24AA256T-I/ST is a 256Kbit EEPROM memory IC manufactured by Microchip Technology, featuring I2C interface communication at 400 kHz with 900 ns access time. The device is packaged in 8-TSSOP surface mount configuration and operates across a supply voltage range of 1.7V to 5.5V with an operating temperature range of -40°C to 85°C. The part maintains Active product status with ROHS3 compliance and unlimited moisture sensitivity rating. Equivalent and substitute parts are identified to address packaging variations, performance enhancements, and alternative manufacturer sourcing while maintaining core functional compatibility.

Key Parameters

Parameter	Value
Memory Size	256Kbit
Memory Organization	32K x 8
Memory Interface	I2C
Clock Frequency	400 kHz
Access Time	900 ns
Write Cycle Time	5ms
Voltage Supply Range	1.7V ~ 5.5V
Operating Temperature	-40°C ~ 85°C
Package Type	8-TSSOP
Mounting Type	Surface Mount
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitute parts are classified into four categories based on substitution relationship type and parameter alignment:

Direct Equivalent (Packaging Variant): 24AA256-I/ST differs only in packaging format (Tube vs. Cut Tape & Digi-Reel), maintaining identical electrical specifications including 400 kHz clock frequency and 900 ns access time.

Manufacturer Recommended (Performance Enhanced): 24FC256T-I/ST, AT24C256C-XHL-T, and M24256-BFDW6TP variants offer improved clock frequency (1 MHz) and reduced access time (400-550 ns) while maintaining 256Kbit capacity and I2C interface. These parts are suitable for applications requiring faster data access.

Parametric Equivalent (Specification Match): 24AA256UIDT-I/ST maintains identical electrical parameters to the main part (400 kHz, 900 ns access time) with verification status difference noted.

Cross-Manufacturer Alternatives (Rohm & STMicroelectronics): BR24G256FVT-3GE2, BR24T256FVT-WE2, and M24256 series variants from Rohm Semiconductor and STMicroelectronics provide functional equivalence with 256Kbit capacity and I2C interface. STMicroelectronics M24256-DRDW3TP/K includes automotive qualification (AEC-Q100) with extended temperature range (-40°C to 125°C).

Key parameters determining substitution eligibility: Memory Size (256Kbit), Memory Organization (32K x 8), Interface Type (I2C), Package Type (8-TSSOP), Voltage Supply Range compatibility, and Operating Temperature Range.

Parameter Comparison

Part Number	Manufacturer	Memory Size	Clock Frequency	Access Time	Voltage Supply	Operating Temp	Package	Inventory
24AA256T-I/ST	Microchip	256Kbit	400 kHz	900 ns	1.7V ~ 5.5V	-40°C ~ 85°C	8-TSSOP	3260 Pcs
24AA256-I/ST	Microchip	256Kbit	400 kHz	900 ns	1.7V ~ 5.5V	-40°C ~ 85°C	8-TSSOP	1314 Pcs
24FC256T-I/ST	Microchip	256Kbit	1 MHz	400 ns	1.7V ~ 5.5V	-40°C ~ 85°C	8-TSSOP	1405 Pcs
AT24C256C-XHL-T	Microchip	256Kbit	1 MHz	550 ns	1.7V ~ 5.5V	-40°C ~ 85°C	8-TSSOP	1193 Pcs
24AA256UIDT-I/ST	Microchip	256Kbit	400 kHz	900 ns	1.7V ~ 5.5V	-40°C ~ 85°C	8-TSSOP	1900 Pcs
BR24G256FVT-3GE2	Rohm	256Kbit	400 kHz	Not specified	1.6V ~ 5.5V	-40°C ~ 85°C	8-TSSOP-B	16373 Pcs
BR24T256FVT-WE2	Rohm	256Kbit	400 kHz	Not specified	1.6V ~ 5.5V	-40°C ~ 85°C	8-TSSOP-B	7325 Pcs
M24256-BFDW6TP	STMicroelectronics	256Kbit	1 MHz	450 ns	1.7V ~ 5.5V	-40°C ~ 85°C	8-TSSOP	1561 Pcs
M24256-BRDW6TP	STMicroelectronics	256Kbit	1 MHz	450 ns	1.8V ~ 5.5V	-40°C ~ 85°C	8-TSSOP	32452 Pcs
M24256-DFDW6TP	STMicroelectronics	256Kbit	400 kHz	450 ns	1.7V ~ 5.5V	-40°C ~ 85°C	8-TSSOP	25300 Pcs
M24256-DRDW3TP/K	STMicroelectronics	256Kbit	1 MHz	450 ns	1.8V ~ 5.5V	-40°C ~ 125°C	8-TSSOP	3300 Pcs

Engineering Selection Recommendations

Direct Substitution (No Design Changes Required): 24AA256-I/ST and 24AA256UIDT-I/ST are electrically and functionally identical to 24AA256T-I/ST. Selection between these parts depends on packaging requirements (Tube vs. Cut Tape & Digi-Reel) and verification status. Both maintain Active product status and ROHS3 compliance.

Performance-Enhanced Substitution (Faster Access): 24FC256T-I/ST, AT24C256C-XHL-T, M24256-BFDW6TP, M24256-BRDW6TP, and M24256-DFDW6TP offer reduced access time (400-550 ns vs. 900 ns) and higher clock frequency (1 MHz vs. 400 kHz). These parts are suitable for applications requiring faster I2C communication without design modifications, as they maintain backward compatibility with 256Kbit capacity and I2C interface.

Cross-Manufacturer Selection: Rohm Semiconductor BR24G256FVT-3GE2 and BR24T256FVT-WE2 provide 256Kbit I2C EEPROM functionality with 400 kHz operation. Note that minimum supply voltage is 1.6V (vs. 1.7V for Microchip parts). STMicroelectronics M24256 series variants offer multiple clock frequency and access time combinations. M24256-DRDW3TP/K includes automotive qualification (AEC-Q100) with extended operating temperature to 125°C, suitable for automotive applications.

Compliance Verification: All listed parts maintain ROHS3 compliance and REACH unaffected status. Moisture sensitivity levels are consistent (MSL 1 - Unlimited) across Microchip and STMicroelectronics parts, with AT24C256C-XHL-T rated MSL 3 (168 Hours).

Frequently Asked Questions (FAQ)

Q: Can 24AA256-I/ST replace 24AA256T-I/ST directly? A: Yes. Both parts are electrically identical with 256Kbit capacity, 400 kHz I2C clock, and 900 ns access time. The difference is packaging format: 24AA256-I/ST uses Tube packaging while 24AA256T-I/ST uses Cut Tape & Digi-Reel. No design changes are required.

Q: What is the difference between 24FC256T-I/ST and 24AA256T-I/ST? A: 24FC256T-I/ST operates at 1 MHz clock frequency with 400 ns access time, compared to 24AA256T-I/ST at 400 kHz and 900 ns. Both maintain 256Kbit capacity and I2C interface. The faster part is suitable for applications requiring higher data throughput.

Q: Are Rohm BR24G256FVT-3GE2 and Microchip 24AA256T-I/ST interchangeable? A: Functionally yes, with one consideration: BR24G256FVT-3GE2 has minimum supply voltage of 1.6V versus 1.7V for the Microchip part. Both operate at 400 kHz with 256Kbit capacity in 8-TSSOP package. Verify your circuit's minimum supply voltage before substitution.

Q: Which substitute part has the fastest access time? A: 24FC256T-I/ST offers the fastest access time at 400 ns with 1 MHz clock frequency. M24256-BFDW6TP, M24256-BRDW6TP, and M24256-DRDW3TP/K also provide 450 ns access time at 1 MHz operation.

Q: Is M24256-DRDW3TP/K suitable for automotive applications? A: Yes. M24256-DRDW3TP/K carries AEC-Q100 automotive qualification with extended operating temperature range of -40°C to 125°C. This part is specifically qualified for automotive use.

Q: What is the difference between 8-TSSOP and 8-TSSOP-B packages? A: Both are 8-pin thin shrink small outline packages with 0.173" width and 4.40mm dimensions. The -B designation indicates a variant used by Rohm Semiconductor. Physical compatibility is maintained for PCB layout purposes.

Q: Can I use AT24C256C-XHL-T if my application requires MSL 1 rating? A: No. AT24C256C-XHL-T is rated MSL 3 (168 Hours), while 24AA256T-I/ST and most alternatives are MSL 1 (Unlimited). If moisture sensitivity level 1 is required, select from Microchip or STMicroelectronics parts with MSL 1 rating.

Q: Which substitute offers the highest inventory availability? A: M24256-BRDW6TP from STMicroelectronics has the highest inventory at 32,452 pieces, followed by M24256-DFDW6TP at 25,300 pieces and BR24G256FVT-3GE2 at 16,373 pieces.

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