AT24C128BW-SH-T Equivalent & Substitute Parts

Part Overview

The AT24C128BW-SH-T is a 128Kbit EEPROM memory IC with I2C interface manufactured by Microchip Technology. This device operates at 1 MHz clock frequency with 550 ns access time and supports a supply voltage range of 1.8V to 5.5V. The part is classified as obsolete, making equivalent and substitute parts necessary for new designs and ongoing production requirements. Substitute parts must maintain functional compatibility across memory capacity, interface protocol, package type, and electrical operating parameters.

Key Parameters

Parameter	Value
Memory Size	128Kbit
Memory Organization	16K x 8
Memory Interface	I2C
Clock Frequency	1 MHz
Access Time	550 ns
Write Cycle Time	5ms
Voltage Supply Range	1.8V ~ 5.5V
Operating Temperature	-40°C ~ 85°C
Package Type	8-SOIC
Mounting Type	Surface Mount
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitution eligibility is determined by strict adherence to the following parameters:

Memory capacity must equal 128Kbit with 16K x 8 organization
I2C interface protocol is mandatory
Package must be 8-SOIC form factor (0.154", 3.90mm Width)
Supply voltage range must encompass or match 1.8V ~ 5.5V
Operating temperature range must match -40°C ~ 85°C
Clock frequency of 1 MHz is preferred but 400 kHz variants are functionally compatible for I2C protocol
Access time and write cycle time must not exceed specified values
Surface mount technology required

Substitute parts are grouped into two categories: direct replacements with identical 1 MHz clock frequency and compatible alternatives with 400 kHz operation that maintain full functional compatibility within I2C protocol specifications.

Parameter Comparison

Part Number	Manufacturer	Memory Size	Clock Frequency	Access Time	Voltage Supply	Package	Product Status	RoHS Status
AT24C128BW-SH-T	Microchip Technology	128Kbit	1 MHz	550 ns	1.8V ~ 5.5V	8-SOIC	Obsolete	ROHS3 Compliant
24AA128-I/SN	Microchip Technology	128Kbit	400 kHz	900 ns	1.7V ~ 5.5V	8-SOIC	Active	ROHS3 Compliant
24AA128T-I/SN	Microchip Technology	128Kbit	400 kHz	900 ns	1.7V ~ 5.5V	8-SOIC	Active	ROHS3 Compliant
24FC128T-I/SN	Microchip Technology	128Kbit	1 MHz	400 ns	1.7V ~ 5.5V	8-SOIC	Active	ROHS3 Compliant
AT24C128C-SSHM-T	Microchip Technology	128Kbit	1 MHz	550 ns	1.7V ~ 5.5V	8-SOIC	Active	ROHS3 Compliant
602-20012	Parallax Inc.	128Kbit	1 MHz	400 ns	1.7V ~ 5.5V	8-SOIC	Active	RoHS Compliant
BR24G128FJ-3AGTE2	Rohm Semiconductor	128Kbit	1 MHz	Not specified	1.7V ~ 5.5V	8-SOIC	Active	ROHS3 Compliant
BR24G128FJ-3GTE2	Rohm Semiconductor	128Kbit	400 kHz	Not specified	1.6V ~ 5.5V	8-SOIC	Active	ROHS3 Compliant
BR24T128FJ-WE2	Rohm Semiconductor	128Kbit	400 kHz	Not specified	1.6V ~ 5.5V	8-SOIC	Active	ROHS3 Compliant
CAT24C128WI-GT3	onsemi	128Kbit	1 MHz	400 ns	1.8V ~ 5.5V	8-SOIC	Active	ROHS3 Compliant
M24128-BRMN6TP	STMicroelectronics	128Kbit	1 MHz	450 ns	1.8V ~ 5.5V	8-SOIC	Active	ROHS3 Compliant

Engineering Selection Recommendations

Primary Substitutes (1 MHz Operation)

AT24C128C-SSHM-T is the recommended primary substitute. It is manufactured by Microchip Technology, the original manufacturer of the AT24C128BW-SH-T, and provides identical 1 MHz clock frequency and 550 ns access time. The part is active in production with ROHS3 compliance and extended supply voltage range (1.7V ~ 5.5V). Inventory availability is substantial at 200,300 units.

24FC128T-I/SN offers superior performance with 400 ns access time while maintaining 1 MHz operation. Also from Microchip Technology, this part is active and ROHS3 compliant with 5,400 units in stock.

CAT24C128WI-GT3 from onsemi provides 1 MHz operation with 400 ns access time and matches the original supply voltage range of 1.8V ~ 5.5V. This part has the highest inventory availability at 3,006,560 units and is ROHS3 compliant.

M24128-BRMN6TP from STMicroelectronics operates at 1 MHz with 450 ns access time. Supply voltage range matches the original at 1.8V ~ 5.5V. The part is active, ROHS3 compliant, and has 80,200 units available.

Secondary Substitutes (400 kHz Operation)

24AA128-I/SN and 24AA128T-I/SN from Microchip Technology operate at 400 kHz, which is compatible with I2C protocol specifications. Both parts are active and ROHS3 compliant. The 24AA128-I/SN is packaged in Tube with 12,600 units in stock, while 24AA128T-I/SN is supplied in Cut Tape format with 9,806 units available.

BR24G128FJ-3AGTE2 from Rohm Semiconductor operates at 1 MHz and is ROHS3 compliant with 2,100 units in stock.

BR24G128FJ-3GTE2 and BR24T128FJ-WE2 from Rohm Semiconductor operate at 400 kHz with extended inventory (55,300 and 1,120 units respectively) and are ROHS3 compliant.

602-20012 from Parallax Inc. operates at 1 MHz with 400 ns access time and is RoHS compliant with 1,071 units available.

Frequently Asked Questions (FAQ)

Q: Can I use a 400 kHz I2C EEPROM as a substitute for the 1 MHz AT24C128BW-SH-T?

A: Yes. The I2C protocol supports multiple clock frequencies. A 400 kHz device will operate correctly in a 1 MHz I2C bus environment, though communication will occur at the lower frequency. The 128Kbit capacity, 16K x 8 organization, and 8-SOIC package ensure mechanical and electrical compatibility.

Q: What is the difference between the AT24C128BW-SH-T and AT24C128C-SSHM-T?

A: Both parts are 128Kbit I2C EEPROMs with 1 MHz operation and 550 ns access time in 8-SOIC packages. The AT24C128C-SSHM-T is the active production equivalent with extended supply voltage range (1.7V vs 1.8V minimum) and higher inventory availability. The "C" designation indicates a newer device revision.

Q: Are all substitute parts ROHS3 compliant?

A: All listed substitutes except 602-20012 are ROHS3 compliant. The 602-20012 from Parallax Inc. is RoHS compliant. Both certifications meet environmental and hazardous substance restrictions for electronic components.

Q: Does package type affect substitution?

A: Yes. All listed substitutes use the 8-SOIC package (0.154", 3.90mm Width) with surface mount technology. This ensures PCB footprint compatibility and assembly process compatibility with the original AT24C128BW-SH-T.

Q: What is the significance of access time differences between substitutes?

A: Access time indicates the delay from address input to data output availability. The original AT24C128BW-SH-T specifies 550 ns. Substitutes with faster access times (400 ns or 450 ns) are fully compatible and provide improved performance. Substitutes with slower access times (900 ns) are compatible but may require timing verification in time-critical applications.

Q: Which substitute offers the best inventory availability?

A: CAT24C128WI-GT3 from onsemi has the highest inventory at 3,006,560 units. This part operates at 1 MHz with 400 ns access time and matches the original supply voltage range of 1.8V ~ 5.5V.

Q: Can I mix different substitute parts in the same design?

A: Yes. All listed substitutes maintain identical memory capacity (128Kbit), organization (16K x 8), interface (I2C), package (8-SOIC), and operating temperature range (-40°C ~ 85°C). Mixing parts with different clock frequencies (1 MHz vs 400 kHz) is permissible within a single I2C bus.

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