AT24C128C-SSHM-B Equivalent & Substitute Parts

Part Overview

The AT24C128C-SSHM-B is a 128Kbit EEPROM memory IC manufactured by Microchip Technology, featuring I2C interface operation at 1 MHz with 550 ns access time. The device is housed in an 8-SOIC surface mount package and operates across a supply voltage range of 1.7V to 5.5V with an operating temperature range of -40°C to 85°C. This part is currently in active product status with verified programmability through DiGi-Electronics. Substitute parts are identified based on matching core electrical parameters: 128Kbit memory capacity, I2C interface protocol, 16K x 8 memory organization, identical package footprint, compatible supply voltage ranges, and matching operating temperature specifications.

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	1.7V ~ 5.5V
Operating Temperature	-40°C ~ 85°C
Package / Case	8-SOIC (0.154", 3.90mm Width)
Mounting Type	Surface Mount
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitution eligibility for the AT24C128C-SSHM-B is determined by the following critical parameters:

Core Electrical Compatibility Requirements:

Memory capacity: 128Kbit
Memory organization: 16K x 8
Interface protocol: I2C
Write cycle time: 5ms
Package type: 8-SOIC with 0.154" (3.90mm) width
Supply voltage range: Must encompass or be compatible with 1.7V ~ 5.5V
Operating temperature range: -40°C ~ 85°C minimum

Performance Considerations:

Clock frequency: 1 MHz operation preferred for direct substitution; 400 kHz variants acceptable for reduced-speed applications
Access time: Faster access times (400 ns) are backward compatible; slower access times (900 ns) may impact timing-critical applications

Compliance & Certification:

RoHS3 compliance required
Moisture sensitivity level and programmability verification noted for design consideration

Substitute parts are grouped into two categories: direct electrical equivalents operating at 1 MHz with matching or superior access times, and functional equivalents operating at reduced clock frequencies (400 kHz) suitable for applications without strict timing requirements.

Parameter Comparison

Part Number	Manufacturer	Memory Size	Clock Frequency	Access Time	Voltage Supply	Package	Operating Temp	RoHS Status
AT24C128C-SSHM-B	Microchip Technology	128Kbit	1 MHz	550 ns	1.7V ~ 5.5V	8-SOIC (3.90mm)	-40°C ~ 85°C	ROHS3
24AA128T-I/SN	Microchip Technology	128Kbit	400 kHz	900 ns	1.7V ~ 5.5V	8-SOIC (3.90mm)	-40°C ~ 85°C	ROHS3
24FC128T-I/SN	Microchip Technology	128Kbit	1 MHz	400 ns	1.7V ~ 5.5V	8-SOIC (3.90mm)	-40°C ~ 85°C	ROHS3
24LC128T-I/SN	Microchip Technology	128Kbit	400 kHz	900 ns	2.5V ~ 5.5V	8-SOIC (3.90mm)	-40°C ~ 85°C	ROHS3
CAT24C128WI-GT3	onsemi	128Kbit	1 MHz	400 ns	1.8V ~ 5.5V	8-SOIC (3.90mm)	-40°C ~ 85°C	ROHS3
BR24G128F-3AGTE2	Rohm Semiconductor	128Kbit	1 MHz	Not specified	1.7V ~ 5.5V	8-SOP (4.40mm)	-40°C ~ 85°C	ROHS3
BR24G128F-3GTE2	Rohm Semiconductor	128Kbit	400 kHz	Not specified	1.6V ~ 5.5V	8-SOP (4.40mm)	-40°C ~ 85°C	ROHS3
BR24G128FJ-3AGTE2	Rohm Semiconductor	128Kbit	1 MHz	Not specified	1.7V ~ 5.5V	8-SOP-J (3.90mm)	-40°C ~ 85°C	ROHS3
BR24G128FJ-3GTE2	Rohm Semiconductor	128Kbit	400 kHz	Not specified	1.6V ~ 5.5V	8-SOP-J (3.90mm)	-40°C ~ 85°C	ROHS3
BR24T128FJ-WE2	Rohm Semiconductor	128Kbit	400 kHz	Not specified	1.6V ~ 5.5V	8-SOP-J (3.90mm)	-40°C ~ 85°C	ROHS3
CAV24C128WE-GT3	onsemi	128Kbit	1 MHz	400 ns	2.5V ~ 5.5V	8-SOIC (3.90mm)	-40°C ~ 125°C	ROHS3

Engineering Selection Recommendations

Direct Electrical Equivalents (1 MHz Operation):

The 24FC128T-I/SN and CAT24C128WI-GT3 provide direct substitution with superior access time performance (400 ns versus 550 ns). Both maintain 1 MHz clock frequency operation and identical 8-SOIC package footprint. The 24FC128T-I/SN is manufactured by Microchip Technology with verified programmability. The CAT24C128WI-GT3 is manufactured by onsemi with programmability not verified through DiGi-Electronics.

The CAV24C128WE-GT3 offers 1 MHz operation with automotive-grade qualification (AEC-Q100) and extended operating temperature range (-40°C to 125°C). This part is suitable for applications requiring automotive compliance. Supply voltage range is limited to 2.5V ~ 5.5V, which may restrict use in low-voltage applications below 2.5V.

Reduced-Speed Functional Equivalents (400 kHz Operation):

The 24AA128T-I/SN and 24LC128T-I/SN are Microchip Technology parts operating at 400 kHz with 900 ns access time. These are suitable for applications where reduced clock frequency is acceptable. The 24LC128T-I/SN has a minimum supply voltage of 2.5V, restricting operation below this threshold compared to the 1.7V minimum of the primary part.

Alternative Manufacturers:

Rohm Semiconductor BR24G128 series parts (BR24G128F-3AGTE2, BR24G128FJ-3AGTE2 for 1 MHz; BR24G128F-3GTE2, BR24G128FJ-3GTE2 for 400 kHz) and BR24T128FJ-WE2 provide functional equivalence with package variations. The 8-SOP-J variants (3.90mm width) maintain footprint compatibility with the original part. The 8-SOP variants (4.40mm width) require PCB layout modification. Programmability verification is not available for Rohm parts through DiGi-Electronics.

Compliance & Certification Status:

All listed substitute parts maintain ROHS3 compliance. The CAV24C128WE-GT3 includes AEC-Q100 automotive qualification. Moisture sensitivity levels vary: Microchip 24FC128T-I/SN and onsemi parts show MSL 1 (Unlimited), while the primary AT24C128C-SSHM-B shows MSL 3 (168 Hours).

Frequently Asked Questions (FAQ)

Q: Can I use a 400 kHz part as a substitute for the 1 MHz AT24C128C-SSHM-B?

A: Yes, if your application does not require 1 MHz clock frequency operation. The 24AA128T-I/SN and 24LC128T-I/SN are functional equivalents with identical memory capacity and organization. Verify that your system firmware or hardware can operate at reduced clock speeds. Access time increases from 550 ns to 900 ns with these parts.

Q: What is the difference between the 8-SOIC and 8-SOP-J packages?

A: Both are 8-pin surface mount packages with similar footprints. The 8-SOIC (0.154", 3.90mm width) and 8-SOP-J (0.154", 3.90mm width) variants from Rohm Semiconductor maintain identical PCB footprint compatibility. The 8-SOP variant (0.173", 4.40mm width) requires PCB layout modification and is not recommended for direct substitution.

Q: Is the CAV24C128WE-GT3 suitable for my application?

A: The CAV24C128WE-GT3 is suitable if your application requires automotive-grade qualification (AEC-Q100) or extended operating temperature range to 125°C. However, the minimum supply voltage is 2.5V, which restricts use in systems operating below this threshold. The primary AT24C128C-SSHM-B operates down to 1.7V.

Q: Why do some substitute parts show "Not Verified" for programmability?

A: Programmability verification through DiGi-Electronics is a specific qualification process. Parts marked "Not Verified" have not undergone this particular verification but remain functional equivalents meeting electrical specifications. Consult manufacturer datasheets for detailed programming specifications.

Q: Can I substitute the AT24C128C-SSHM-B with a part from a different manufacturer?

A: Yes. The onsemi CAT24C128WI-GT3 and Rohm Semiconductor BR24G128 series provide functional equivalence with matching memory capacity, organization, and interface protocol. Verify package compatibility and supply voltage requirements for your specific application.

Q: What is the impact of different access times on system performance?

A: Access time determines the delay between address presentation and data availability. The primary part specifies 550 ns. Faster alternatives (400 ns) are backward compatible. Slower alternatives (900 ns) may impact timing-critical read operations. Verify your system timing requirements against the datasheet specifications.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. All listed substitute parts maintain ROHS3 compliance, matching the environmental compliance status of the primary AT24C128C-SSHM-B.

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