24LC21-I/P EEPROM Memory IC Equivalent & Substitute Parts

Part Overview

The 24LC21-I/P is a 1Kbit EEPROM memory integrated circuit manufactured by Microchip Technology, designed for I2C serial communication applications operating at 400 kHz. This through-hole 8-DIP package component is actively produced and widely used in embedded systems requiring non-volatile memory storage. Substitute parts are identified when equivalent electrical specifications and mechanical compatibility are maintained within the allowed parameter ranges for this EEPROM category.

Substiute Parts

24LC21-I/P

Microchip TechnologyIn Stock: 70024LC21-I/P Datasheet

Current PartRFQ

24AA01-I/P

Microchip TechnologyIn Stock: 251224AA01-I/P Datasheet

MFR RecommendedRFQ

24LC01B-I/P

Microchip TechnologyIn Stock: 1031124LC01B-I/P Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the 24LC21-I/P are qualified based on the following critical parameters that must remain constant or within acceptable ranges:

• Memory capacity: 1Kbit (128 x 8 organization)
• Interface protocol: I2C serial communication
• Clock frequency: 400 kHz operation
• Package type: 8-DIP through-hole configuration with 0.300" (7.62mm) pitch
• Operating temperature range: -40°C to 85°C
• Compliance certifications: ROHS3, REACH Unaffected, EAR99 classification

Variations in access time and write cycle time are permitted within the electrical specifications of each part number, as these parameters do not affect functional compatibility in I2C bus applications. Supply voltage ranges may differ between substitute parts while maintaining overlap with system requirements.

Parameter Comparison

Engineering Selection Recommendations

All three parts—24LC21-I/P, 24LC01B-I/P, and 24AA01-I/P—are actively manufactured by Microchip Technology and maintain full ROHS3 compliance and REACH Unaffected status. Selection between these parts depends on system-level requirements:

The 24LC21-I/P offers the fastest access time at 900 ns and operates within a 2.5V to 5.5V supply range. The 24LC01B-I/P provides identical supply voltage specifications with longer access time (4.6 µs) and reduced write cycle time (5 ms). The 24AA01-I/P extends the minimum supply voltage to 1.7V, enabling operation in lower-voltage applications, while maintaining the same 5 ms write cycle time as the 24LC01B-I/P.

All parts share identical memory capacity, organization, I2C interface, clock frequency, operating temperature range, and 8-DIP package configuration, ensuring direct mechanical and functional interchangeability within systems designed for any of these specifications.

Frequently Asked Questions (FAQ)

Q: Can 24LC01B-I/P replace 24LC21-I/P in existing designs?

A: Yes. Both parts maintain identical memory capacity (1Kbit), organization (128 x 8), I2C interface, 400 kHz clock frequency, 8-DIP package configuration, and operating temperature range (-40°C to 85°C). The 24LC01B-I/P has longer access time (4.6 µs vs. 900 ns) and shorter write cycle time (5 ms vs. 10 ms), which do not prevent functional substitution in I2C applications.

Q: What is the key difference between 24AA01-I/P and 24LC21-I/P?

A: The 24AA01-I/P supports a lower minimum supply voltage (1.7V vs. 2.5V), making it suitable for battery-powered or low-voltage systems. All other electrical and mechanical parameters remain equivalent.

Q: Are all three parts pin-compatible?

A: Yes. All three parts use the 8-DIP (0.300", 7.62mm) through-hole package with identical pin configuration, enabling direct socket substitution.

Q: Do these parts require different PCB layouts?

A: No. The identical 8-DIP package and pin pitch ensure that no PCB layout modifications are necessary when substituting between these parts.

Q: Are all parts RoHS compliant?

A: Yes. All three parts are ROHS3 compliant and REACH Unaffected, meeting current environmental and regulatory requirements.