AT89C51-24PI Equivalent & Substitute Parts

Part Overview

The AT89C51-24PI is an 8-bit microcontroller from Microchip Technology's 89C series, featuring 4KB of FLASH program memory and operating at 24MHz. This device is classified as obsolete, which necessitates identification of functionally equivalent alternatives for new designs and production continuity. The part operates within a 4V to 6V supply range and includes 32 I/O pins with UART/USART connectivity in a 40-DIP through-hole package.

Substiute Parts

AT89C51-24PI

Microchip TechnologyIn Stock: 18864AT89C51-24PI Datasheet

Current PartRFQ

AT89S51-24PU

Microchip TechnologyIn Stock: 11094AT89S51-24PU Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the AT89C51-24PI is determined by the following critical parameters:

• Core Architecture: Both 80C51 and 8051 cores are compatible within the 89-series microcontroller family
• Memory Configuration: Program memory must be 4KB FLASH; RAM must be 128 x 8
• Operating Speed: 24MHz operation is required
• I/O Count: 32 I/O pins minimum
• Package: 40-DIP through-hole form factor with identical pin spacing (0.600", 15.24mm)
• Supply Voltage: Operating range must encompass the application requirements
• Connectivity: UART/USART interface must be present

The AT89S51-24PU qualifies as a direct substitute based on these parameters. The primary distinction is the series designation (89S versus 89C) and product status transition from obsolete to active.

Parameter Comparison

Engineering Selection Recommendations

The AT89S51-24PU is the qualified substitute for the AT89C51-24PI based on the following factors:

• Product Status: The AT89S51-24PU maintains active production status with 11,000 units in stock, ensuring supply continuity for the obsolete AT89C51-24PI
• Regulatory Compliance: The AT89S51-24PU is ROHS3 compliant, whereas the AT89C51-24PI is non-compliant, making the substitute the appropriate choice for applications subject to RoHS requirements
• Functional Equivalence: All critical electrical and mechanical parameters align, including core architecture compatibility, memory configuration, speed, I/O count, and package form factor
• Supply Voltage Consideration: The AT89S51-24PU operates within 4V to 5.5V, which is a subset of the AT89C51-24PI range (4V to 6V). Applications operating above 5.5V require voltage verification

Frequently Asked Questions (FAQ)

Q: Can the AT89S51-24PU directly replace the AT89C51-24PI in existing designs?

A: Yes, the AT89S51-24PU is a direct functional replacement. Both devices share identical pin configurations, memory architecture, speed ratings, and I/O specifications in the same 40-DIP package. No PCB modifications are required.

Q: What is the difference between the 89C and 89S series designations?

A: The 89C and 89S designations represent different product lines within Microchip's 8051-compatible microcontroller family. The 89S series (represented by AT89S51-24PU) is the active production line, while the 89C series (AT89C51-24PI) has reached end-of-life status.

Q: Are there voltage supply differences between these parts?

A: The AT89C51-24PI operates at 4V to 6V, while the AT89S51-24PU operates at 4V to 5.5V. If your application requires operation above 5.5V, the substitute may not be suitable without circuit redesign.

Q: Is the AT89S51-24PU RoHS compliant?

A: Yes, the AT89S51-24PU is ROHS3 compliant. The original AT89C51-24PI is RoHS non-compliant. This makes the substitute the required choice for applications subject to RoHS regulations.

Q: Are the packages identical?

A: Yes, both parts use the 40-DIP (0.600", 15.24mm) through-hole package with identical pin spacing and mechanical dimensions.

Q: What is the inventory status for the substitute part?

A: The AT89S51-24PU has 11,000 units in new original stock, providing adequate supply for production requirements.