AT24C08B-TSU-T Equivalent & Substitute Parts

Part Overview

The AT24C08B-TSU-T is an 8Kbit EEPROM memory IC with I2C interface manufactured by Microchip Technology. This device operates at 1 MHz clock frequency with 550 ns access time and is housed in a SOT-23-5 surface mount package. The part is currently obsolete, with 953 units available in inventory as new original stock. Identification of equivalent and substitute parts is necessary to maintain design continuity and ensure component availability for production and repair applications.

Key Parameters

Parameter	Value
Memory Size	8Kbit
Memory Format	EEPROM
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	SOT-23-5
Mounting Type	Surface Mount
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitution of the AT24C08B-TSU-T is determined by the following critical parameters: 8Kbit memory capacity, EEPROM non-volatile memory format, I2C serial interface, SOT-23-5 surface mount package, and compatible voltage supply range. Substitute parts must maintain electrical compatibility across these core specifications.

Substitute parts are grouped into two categories based on operational characteristics:

Category 1: Direct Functional Equivalents (1 MHz Operation) Parts operating at 1 MHz clock frequency with access times of 400–550 ns provide direct functional equivalence to the AT24C08B-TSU-T. These include AT24CS08-STUM-T, CAT24AA08TDI-GT3, and S-24C08DI-M5T1U5.

Category 2: Compatible Alternatives (400 kHz Operation) Parts operating at 400 kHz clock frequency with 900 ns access time provide functional compatibility for applications where lower clock speed is acceptable. These include 24AA08T-I/OT, 24LC08BT-E/OT, and 24LC08BT-I/OT.

All substitute parts maintain 8Kbit capacity, I2C interface, SOT-23-5 packaging, and ROHS3 compliance. Voltage supply ranges and operating temperature ranges vary among substitutes and must be verified against application requirements.

Parameter Comparison

Part Number	Manufacturer	Memory Size	Clock Frequency	Access Time	Voltage Supply	Operating Temperature	Package	Product Status
AT24C08B-TSU-T	Microchip Technology	8Kbit	1 MHz	550 ns	1.8V ~ 5.5V	-40°C ~ 85°C	SOT-23-5	Obsolete
AT24CS08-STUM-T	Microchip Technology	8Kbit	1 MHz	550 ns	1.7V ~ 5.5V	-40°C ~ 85°C	SOT-23-5	Active
CAT24AA08TDI-GT3	onsemi	8Kbit	1 MHz	400 ns	1.7V ~ 5.5V	-40°C ~ 85°C	TSOT-23-5	Last Time Buy
S-24C08DI-M5T1U5	ABLIC Inc.	8Kbit	1 MHz	500 ns	1.7V ~ 5.5V	-40°C ~ 85°C	SOT-23-5	Active
24AA08T-I/OT	Microchip Technology	8Kbit	400 kHz	900 ns	1.7V ~ 5.5V	-40°C ~ 85°C	SOT-23-5	Active
24LC08BT-E/OT	Microchip Technology	8Kbit	400 kHz	900 ns	2.5V ~ 5.5V	-40°C ~ 125°C	SOT-23-5	Active
24LC08BT-I/OT	Microchip Technology	8Kbit	400 kHz	900 ns	2.5V ~ 5.5V	-40°C ~ 85°C	SOT-23-5	Active

Engineering Selection Recommendations

Primary Recommendation: AT24CS08-STUM-T This Microchip Technology part provides identical electrical performance to the AT24C08B-TSU-T with 1 MHz clock frequency and 550 ns access time. The part is currently in active production status with 15,100 units in inventory. It maintains ROHS3 compliance and extends voltage supply compatibility to 1.7V minimum. This part is the preferred direct replacement.

Secondary Recommendation: S-24C08DI-M5T1U5 This ABLIC Inc. part operates at 1 MHz with 500 ns access time, providing performance equivalent to the original part. The device is in active production status with 4,200 units available. It maintains ROHS3 compliance and operates across the same temperature range as the original part.

Alternative for Extended Temperature Range: 24LC08BT-E/OT This Microchip Technology part extends operating temperature to -40°C ~ 125°C, suitable for applications requiring enhanced thermal performance. However, it operates at 400 kHz clock frequency and requires minimum supply voltage of 2.5V. This part is appropriate only when lower clock speed and higher minimum voltage are acceptable.

Alternative for Lower Voltage Applications: 24AA08T-I/OT This Microchip Technology part supports supply voltage down to 1.7V and operates at 400 kHz. It is suitable for low-power applications where reduced clock frequency is acceptable.

Not Recommended: CAT24AA08TDI-GT3 This onsemi part is in Last Time Buy status, indicating discontinued production. While it provides 1 MHz operation with superior 400 ns access time, its limited availability and end-of-life status make it unsuitable for new designs or long-term production requirements.

Frequently Asked Questions (FAQ)

Q: Can I use a 400 kHz substitute part in place of the 1 MHz AT24C08B-TSU-T? A: Substitution is possible only if the application design does not require 1 MHz clock frequency operation. The 24AA08T-I/OT and 24LC08BT series parts operate at 400 kHz and provide the same 8Kbit capacity and I2C interface. System timing and communication protocols must be verified to confirm compatibility with reduced clock speed.

Q: What is the difference between SOT-23-5 and TSOT-23-5 packages? A: Both designations refer to the same 5-pin surface mount package with identical pin configuration and footprint. TSOT-23-5 indicates a thin variant. The CAT24AA08TDI-GT3 uses TSOT-23-5 designation while other parts use SOT-23-5, but both are mechanically and electrically compatible for PCB assembly.

Q: Does the AT24CS08-STUM-T require any design changes compared to the AT24C08B-TSU-T? A: No design changes are required. The AT24CS08-STUM-T provides identical electrical performance with 1 MHz clock frequency, 550 ns access time, and I2C interface. Pin configuration and package footprint are identical. The part is a direct replacement.

Q: Why is the CAT24AA08TDI-GT3 marked as Last Time Buy? A: Last Time Buy status indicates that onsemi has discontinued production of this part. While inventory is currently available (4,170 units), future availability cannot be guaranteed. This status makes the part unsuitable for new production designs requiring long-term component supply.

Q: What voltage supply range should I verify for my application? A: The original AT24C08B-TSU-T operates from 1.8V to 5.5V. Substitute parts vary: AT24CS08-STUM-T and CAT24AA08TDI-GT3 operate from 1.7V minimum, while 24LC08BT series parts require 2.5V minimum. Verify that your application's power supply voltage falls within the selected substitute part's specified range.

Q: Are all substitute parts ROHS3 compliant? A: Yes. All substitute parts listed in this document maintain ROHS3 compliance status, matching the original AT24C08B-TSU-T specification.

Q: Can I use 24LC08BT-E/OT for applications requiring -40°C to 125°C operation? A: Yes. The 24LC08BT-E/OT is rated for -40°C to 125°C operating temperature, extending the upper temperature limit by 40°C compared to the original part. However, this part operates at 400 kHz clock frequency and requires minimum 2.5V supply voltage. Verify that these specifications are compatible with your application requirements.

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