AT21CS01-SSHM16-T Equivalent & Substitute Parts

Part Overview

The AT21CS01-SSHM16-T is a 1Kbit EEPROM memory IC manufactured by Microchip Technology, featuring I2C and Single Wire interface capability at 125 kbps clock frequency. This component is classified as Active product status with full RoHS3 compliance and REACH unaffected designation. Substitute parts are identified when equivalent memory capacity, interface protocol, package form factor, and electrical operating parameters align within specified tolerances, enabling direct replacement in applications where the original part becomes unavailable or inventory constraints require alternative sourcing.

Key Parameters

Parameter	Value
Memory Size	1Kbit
Memory Organization	128 x 8
Memory Interface	I2C, Single Wire
Clock Frequency	125 kbps
Write Cycle Time	5ms
Voltage Supply Range	1.7V ~ 3.6V
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 AT21CS01-SSHM16-T is determined by the following critical parameters:

Memory capacity must equal 1Kbit with 128 x 8 organization
Package form factor must be 8-SOIC with identical 0.154" (3.90mm) width
Memory interface must support I2C protocol
Write cycle time must not exceed 5ms
Voltage supply range must encompass the operating envelope of the original part
Operating temperature range must cover -40°C to 85°C minimum
RoHS3 compliance and REACH unaffected status must be maintained

The 24AA01T-I/SN meets all substitution criteria as a Microchip Technology EEPROM with identical memory capacity, organization, package geometry, and compliance certifications.

Parameter Comparison

Parameter	AT21CS01-SSHM16-T	24AA01T-I/SN	Compatibility
Memory Size	1Kbit	1Kbit	Equivalent
Memory Organization	128 x 8	128 x 8	Equivalent
Memory Interface	I2C, Single Wire	I2C	Compatible
Clock Frequency	125 kbps	400 kHz	Substitute supports higher frequency
Write Cycle Time	5ms	5ms	Equivalent
Access Time	Not specified	3500 ns	Substitute specified
Voltage Supply Range	1.7V ~ 3.6V	1.7V ~ 5.5V	Substitute range encompasses original
Operating Temperature	-40°C ~ 85°C	-40°C ~ 85°C	Equivalent
Package / Case	8-SOIC (0.154", 3.90mm Width)	8-SOIC (0.154", 3.90mm Width)	Equivalent
Mounting Type	Surface Mount	Surface Mount	Equivalent
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	Equivalent
Moisture Sensitivity Level	3 (168 Hours)	3 (168 Hours)	Equivalent
REACH Status	REACH Unaffected	REACH Unaffected	Equivalent

Engineering Selection Recommendations

The 24AA01T-I/SN qualifies as a direct substitute for the AT21CS01-SSHM16-T based on the following engineering criteria:

Both components maintain Active product status with verified availability through authorized distribution channels. Electrical parameter alignment includes identical memory capacity, organization, write cycle timing, and operating temperature specifications. Package geometry and mounting type are identical, ensuring mechanical compatibility in existing PCB layouts without redesign requirements.

The substitute part demonstrates enhanced electrical specifications: the 400 kHz clock frequency exceeds the original 125 kbps specification, and the 1.7V to 5.5V supply voltage range encompasses the original 1.7V to 3.6V envelope. These enhanced parameters provide operational margin without introducing incompatibility.

Both parts maintain equivalent compliance certifications: RoHS3 compliance, REACH unaffected status, and identical moisture sensitivity levels ensure regulatory and environmental consistency. The substitute part carries Digi-Electronics Verified programmability status, confirming functional validation.

Frequently Asked Questions (FAQ)

Q: Can the 24AA01T-I/SN replace the AT21CS01-SSHM16-T in existing designs without PCB modification?

A: Yes. Both components use identical 8-SOIC package geometry with 0.154" (3.90mm) width and surface mount configuration. Pin-to-pin compatibility and footprint alignment enable direct substitution without PCB redesign.

Q: What is the significance of the higher 400 kHz clock frequency in the substitute part?

A: The 24AA01T-I/SN operates at 400 kHz compared to the original 125 kbps specification. This enhanced frequency provides faster data transfer capability while maintaining backward compatibility with systems designed for the lower frequency. The substitute will function correctly in applications limited to 125 kbps operation.

Q: Does the expanded voltage supply range of the 24AA01T-I/SN (1.7V ~ 5.5V) affect compatibility?

A: No. The substitute part's wider supply voltage range (1.7V ~ 5.5V) encompasses the original specification (1.7V ~ 3.6V). The component will operate correctly within the original design voltage envelope and provides additional flexibility for future applications requiring higher supply voltages.

Q: Are there interface differences between the I2C/Single Wire capability of the original and the I2C-only specification of the substitute?

A: The AT21CS01-SSHM16-T supports both I2C and Single Wire protocols. The 24AA01T-I/SN supports I2C protocol. Applications utilizing only I2C interface will experience no functional difference. Applications requiring Single Wire protocol operation must retain the original AT21CS01-SSHM16-T component.

Q: Do both parts maintain equivalent compliance and regulatory status?

A: Yes. Both components are RoHS3 compliant, REACH unaffected, and carry identical moisture sensitivity levels (MSL 3, 168 hours). Regulatory and environmental compliance requirements are maintained with the substitute part.

Q: What is the inventory status difference between these parts?

A: The AT21CS01-SSHM16-T shows 977 pieces in stock. The 24AA01T-I/SN shows 18,996 pieces in stock through authorized distribution. The substitute part offers significantly higher availability for immediate procurement.

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