24AA256T/SM EEPROM Memory IC Equivalent & Substitute Parts

Part Overview

The 24AA256T/SM is a 256Kbit I2C EEPROM memory IC manufactured by Microchip Technology in an 8-SOIJ surface mount package. This non-volatile memory device operates at 400 kHz clock frequency with 900 ns access time and supports a supply voltage range of 1.7V to 5.5V. The part is actively produced and RoHS3 compliant. Substitute parts are identified when equivalent memory capacity, interface protocol, and electrical specifications align with application requirements while accommodating variations in packaging, speed grade, and operating temperature range.

Key Parameters

Parameter	24AA256T/SM
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	0°C ~ 70°C
Package Type	8-SOIC (0.209", 5.30mm Width)
Mounting Type	Surface Mount
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitute parts for the 24AA256T/SM are qualified based on the following core parameters:

Memory Capacity: 256Kbit (32K x 8 organization) — all substitutes maintain identical capacity
Interface Protocol: I2C — all substitutes use I2C communication
Supply Voltage: Minimum 1.7V support required; substitutes with 1.8V minimum are compatible in applications using ≥1.8V
Write Cycle Time: 5ms — all substitutes match this specification
Package Compatibility: 8-SOIC variants with equivalent pin configuration and similar physical dimensions
Compliance: RoHS3 and REACH compliance maintained across all substitutes

Substitutes are grouped by manufacturer and performance tier. Higher clock frequency variants (1 MHz) offer improved access time but remain functionally compatible in 400 kHz I2C systems. Automotive-grade variants with extended temperature ranges and AEC-Q100 qualification serve specialized applications.

Parameter Comparison

Parameter	24AA256T/SM	24FC256T-I/SM	BR24S256F-WE2	M24256-BRMN6P	M24256-BRMN6TP	M24256-DRMN3TP/K	M24256-DRMN8TP/K
Manufacturer	Microchip	Microchip	Rohm	STMicroelectronics	STMicroelectronics	STMicroelectronics	STMicroelectronics
Memory Size	256Kbit	256Kbit	256Kbit	256Kbit	256Kbit	256Kbit	256Kbit
Memory Organization	32K x 8	32K x 8	32K x 8	32K x 8	32K x 8	32K x 8	32K x 8
Interface	I2C	I2C	I2C	I2C	I2C	I2C	I2C
Clock Frequency	400 kHz	1 MHz	400 kHz	1 MHz	1 MHz	1 MHz	1 MHz
Access Time	900 ns	400 ns	Not specified	450 ns	450 ns	450 ns	450 ns
Write Cycle Time	5ms	5ms	5ms	5ms	5ms	5ms	5ms
Supply Voltage	1.7V ~ 5.5V	1.7V ~ 5.5V	1.7V ~ 5.5V	1.8V ~ 5.5V	1.8V ~ 5.5V	1.8V ~ 5.5V	1.8V ~ 5.5V
Operating Temperature	0°C ~ 70°C	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 125°C	-40°C ~ 105°C
Package	8-SOIJ (5.30mm)	8-SOIJ (5.30mm)	8-SOP (4.40mm)	8-SOIC (3.90mm)	8-SOIC (3.90mm)	8-SOIC (3.90mm)	8-SOIC (3.90mm)
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Automotive Grade	No	No	No	No	No	Yes (AEC-Q100)	Yes (AEC-Q100)

Engineering Selection Recommendations

Direct Replacement (Same Performance Tier)

24FC256T-I/SM serves as a direct Microchip alternative with identical supply voltage range and package footprint. This part operates at 1 MHz clock frequency with 400 ns access time, providing improved performance while maintaining full backward compatibility in 400 kHz I2C systems. Extended operating temperature range (-40°C to 85°C) supports broader application environments.

Cross-Manufacturer Substitutes (Standard Grade)

BR24S256F-WE2 (Rohm Semiconductor) and M24256-BRMN6P/M24256-BRMN6TP (STMicroelectronics) provide functionally equivalent 256Kbit I2C EEPROM solutions. All three maintain 400 kHz or 1 MHz operation with 5ms write cycle time. Package dimensions vary: BR24S256F-WE2 uses 8-SOP (4.40mm width) while STMicroelectronics variants use 8-SOIC (3.90mm width). These parts support extended temperature ranges and are RoHS3 compliant. Selection depends on PCB layout constraints and available inventory.

Automotive-Grade Substitutes (Extended Temperature)

M24256-DRMN3TP/K and M24256-DRMN8TP/K are AEC-Q100 qualified automotive-grade variants from STMicroelectronics. M24256-DRMN3TP/K operates to 125°C while M24256-DRMN8TP/K operates to 105°C. Both maintain 1 MHz clock frequency, 450 ns access time, and 1.8V to 5.5V supply range. These parts are specified for automotive and industrial applications requiring extended temperature performance and formal qualification documentation.

Voltage Compatibility Note

The 24AA256T/SM supports 1.7V minimum supply voltage. STMicroelectronics and Rohm substitutes specify 1.8V minimum. In applications operating below 1.8V, only Microchip variants (24AA256T/SM and 24FC256T-I/SM) are suitable.

Frequently Asked Questions (FAQ)

Q: Can 24FC256T-I/SM replace 24AA256T/SM in existing designs?

A: Yes. Both are Microchip I2C EEPROM devices with identical 256Kbit capacity, 32K x 8 organization, 5ms write cycle time, and 1.7V to 5.5V supply range. The 24FC256T-I/SM operates at 1 MHz (versus 400 kHz) with 400 ns access time (versus 900 ns), providing performance improvement. Pin configuration and I2C protocol are identical. Extended temperature range (-40°C to 85°C) may benefit temperature-sensitive applications.

Q: Are STMicroelectronics M24256 variants pin-compatible with Microchip 24AA256T/SM?

A: Yes. All 256Kbit I2C EEPROM devices in 8-SOIC packages share identical pin configuration and I2C protocol. Physical package dimensions differ slightly (3.90mm versus 5.30mm width), requiring PCB layout verification. Electrical specifications are compatible when supply voltage is ≥1.8V.

Q: What is the difference between M24256-BRMN6TP and M24256-DRMN3TP/K?

A: Both are STMicroelectronics 256Kbit I2C EEPROM devices with 1 MHz operation and 450 ns access time. M24256-BRMN6TP is standard industrial grade (-40°C to 85°C). M24256-DRMN3TP/K is automotive-grade AEC-Q100 qualified with extended temperature range (-40°C to 125°C) and formal qualification documentation for automotive applications.

Q: Can BR24S256F-WE2 be used in place of 24AA256T/SM?

A: Yes, with package dimension verification. BR24S256F-WE2 is a Rohm 256Kbit I2C EEPROM with 400 kHz operation, 5ms write cycle, and 1.7V to 5.5V supply range. The 8-SOP package (4.40mm width) differs from the 24AA256T/SM 8-SOIJ package (5.30mm width). Pin configuration is identical. PCB layout must accommodate the narrower package width.

Q: Which substitute supports the lowest supply voltage?

A: 24AA256T/SM and 24FC256T-I/SM both support 1.7V minimum supply voltage. All other substitutes (Rohm and STMicroelectronics) specify 1.8V minimum. For applications operating below 1.8V, only Microchip variants are suitable.

Q: Are automotive-grade M24256 variants necessary for non-automotive applications?

A: No. Automotive-grade variants (M24256-DRMN3TP/K and M24256-DRMN8TP/K) are specified for automotive and industrial applications requiring AEC-Q100 qualification and extended temperature operation. Standard-grade variants are appropriate for consumer and commercial applications within 0°C to 85°C operating range.

Q: What is the inventory status of substitute parts?

A: 24FC256T-I/SM: 3,300 units. BR24S256F-WE2: 9,900 units. M24256-BRMN6P: 3,375 units. M24256-BRMN6TP: 30,200 units. M24256-DRMN3TP/K: 15,675 units. M24256-DRMN8TP/K: 24,279 units. All parts are new original stock and RoHS3 compliant.

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