AT24C01B-TH-T Equivalent & Substitute Parts

Part Overview

The AT24C01B-TH-T is a 1Kbit EEPROM memory IC manufactured by Microchip Technology, featuring I2C interface operation at 1 MHz with 550 ns access time. The device is packaged in 8-TSSOP surface mount configuration and operates across a supply voltage range of 1.8V to 5.5V with temperature range of -40°C to 85°C. This part is currently listed as obsolete, necessitating identification of active equivalent and substitute components that maintain functional compatibility for existing designs.

Key Parameters

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

Substitute Part Grouping Explanation

Substitution of the AT24C01B-TH-T is determined by strict equivalence in the following parameters: memory size (1Kbit), memory organization (128 x 8), I2C interface protocol, package type (8-TSSOP), operating temperature range (-40°C to 85°C), and RoHS3 compliance status. Substitute parts are grouped into two categories based on clock frequency capability:

Category 1: 1 MHz Operation (Direct Functional Equivalents) Parts operating at 1 MHz clock frequency with 550 ns access time provide direct functional replacement with identical performance characteristics. These include AT24CS01-XHM-T (Microchip) and BR24G01FVT-3AGE2 (Rohm Semiconductor).

Category 2: 400 kHz Operation (Reduced Speed Substitutes) Parts operating at 400 kHz clock frequency with 900 ns or 3500 ns access time are functionally compatible for applications where reduced I2C bus speed is acceptable. These include 24AA014H-I/ST, 24AA014HT-I/ST, 24AA014T-I/ST, 24AA01HT-I/ST, 24AA01T-I/ST (Microchip), BR24G01FVT-3GE2, and BR24T01FVT-WE2 (Rohm Semiconductor).

All substitute parts maintain I2C protocol compatibility, identical memory capacity, and compatible voltage supply ranges (minimum 1.6V to 1.8V, maximum 5.5V).

Parameter Comparison

Part Number	Manufacturer	Memory Size	Clock Frequency	Access Time	Voltage Supply	Package	Product Status
AT24C01B-TH-T	Microchip Technology	1Kbit	1 MHz	550 ns	1.8V ~ 5.5V	8-TSSOP	Obsolete
AT24CS01-XHM-T	Microchip Technology	1Kbit	1 MHz	550 ns	1.7V ~ 5.5V	8-TSSOP	Active
BR24G01FVT-3AGE2	Rohm Semiconductor	1Kbit	1 MHz	Not specified	1.6V ~ 5.5V	8-TSSOP-B	Active
24AA014H-I/ST	Microchip Technology	1Kbit	400 kHz	900 ns	1.7V ~ 5.5V	8-TSSOP	Active
24AA014HT-I/ST	Microchip Technology	1Kbit	400 kHz	900 ns	1.7V ~ 5.5V	8-TSSOP	Active
24AA014T-I/ST	Microchip Technology	1Kbit	400 kHz	900 ns	1.7V ~ 5.5V	8-TSSOP	Active
24AA01HT-I/ST	Microchip Technology	1Kbit	400 kHz	900 ns	1.7V ~ 5.5V	8-TSSOP	Active
24AA01T-I/ST	Microchip Technology	1Kbit	400 kHz	3500 ns	1.7V ~ 5.5V	8-TSSOP	Active
BR24G01FVT-3GE2	Rohm Semiconductor	1Kbit	400 kHz	Not specified	1.6V ~ 5.5V	8-TSSOP-B	Active
BR24T01FVT-WE2	Rohm Semiconductor	1Kbit	400 kHz	Not specified	1.6V ~ 5.5V	8-TSSOP-B	Active

Engineering Selection Recommendations

For direct replacement of the AT24C01B-TH-T in applications requiring 1 MHz I2C operation, AT24CS01-XHM-T is the primary active equivalent from Microchip Technology. This part maintains identical clock frequency (1 MHz) and access time (550 ns) specifications, ensuring no timing modifications are required in existing designs. AT24CS01-XHM-T carries active product status with 25,400 units in stock and maintains ROHS3 compliance.

BR24G01FVT-3AGE2 from Rohm Semiconductor provides an alternative 1 MHz equivalent with active product status. This part uses 8-TSSOP-B package variant and operates across 1.6V to 5.5V supply range, offering broader low-voltage compatibility than the original part.

For applications where I2C bus speed reduction to 400 kHz is acceptable, multiple active alternatives exist from both Microchip Technology and Rohm Semiconductor. Microchip 24AA014 and 24AA01 series parts (24AA014H-I/ST, 24AA014HT-I/ST, 24AA014T-I/ST, 24AA01HT-I/ST, 24AA01T-I/ST) provide 400 kHz operation with varying access times and packaging options. Rohm BR24G01FVT-3GE2 and BR24T01FVT-WE2 offer 400 kHz alternatives with 8-TSSOP-B packaging.

All recommended substitutes maintain ROHS3 compliance, identical memory capacity (1Kbit, 128 x 8 organization), I2C protocol compatibility, and -40°C to 85°C operating temperature range. Selection between substitutes should consider specific application I2C bus speed requirements, packaging preferences (standard 8-TSSOP versus 8-TSSOP-B), and supply voltage operating margins.

Frequently Asked Questions (FAQ)

Q: Can 24AA014HT-I/ST replace AT24C01B-TH-T directly without circuit modifications?

A: 24AA014HT-I/ST is functionally compatible but operates at 400 kHz I2C clock frequency versus the original 1 MHz. If your application I2C bus is configured for 1 MHz operation, the substitute will operate at reduced speed without causing circuit malfunction. No hardware modifications are required; however, I2C bus timing may need adjustment if the application enforces strict 1 MHz operation.

Q: What is the difference between 8-TSSOP and 8-TSSOP-B packages?

A: Both packages are physically compatible 8-pin thin shrink small outline packages with identical 0.173" width and 4.40mm dimensions. The -B variant indicates a package design revision from Rohm Semiconductor. Pin configuration and footprint remain compatible for PCB assembly purposes.

Q: Is AT24CS01-XHM-T a true 1:1 replacement for AT24C01B-TH-T?

A: AT24CS01-XHM-T maintains identical 1 MHz clock frequency and 550 ns access time specifications, making it functionally equivalent for timing-critical applications. The part operates across 1.7V to 5.5V supply range (versus original 1.8V to 5.5V), providing slightly broader low-voltage compatibility. Both parts are ROHS3 compliant with identical memory organization and I2C interface protocol.

Q: Why do some substitutes show different access times (900 ns or 3500 ns)?

A: Access time represents the delay from I2C address/command transmission to data availability. Longer access times (900 ns or 3500 ns) indicate slower memory response compared to the original 550 ns specification. These parts remain functionally compatible with I2C protocol but may require longer read cycle times in applications with strict timing constraints.

Q: Are Rohm Semiconductor parts (BR24G01, BR24T01 series) fully compatible with Microchip designs?

A: Rohm parts maintain I2C protocol compatibility, identical memory capacity, and compatible package dimensions. Both manufacturers implement standard I2C EEPROM interface specifications. Cross-manufacturer substitution is supported by identical functional parameters; however, verify specific device datasheets for any manufacturer-specific timing or electrical characteristic variations.

Q: What inventory considerations apply when selecting substitutes?

A: AT24CS01-XHM-T offers the highest inventory availability (25,400 units) among 1 MHz equivalents. For 400 kHz alternatives, 24AA01T-I/ST provides 4,182 units in stock. Rohm parts show lower inventory levels (712-1,284 units). Inventory status should be considered for production volume requirements and supply chain continuity.

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