P87C51RC2FN,112 Equivalent & Substitute Parts

Part Overview

The P87C51RC2FN,112 is an 8051-based 8-bit microcontroller manufactured by NXP Semiconductors, featuring 32KB OTP program memory, 512 bytes of RAM, and a 33MHz operating frequency. This device is classified as obsolete, making equivalent and substitute parts necessary for ongoing system support, redesigns, and new production runs. The part is housed in a 40-DIP package with a supply voltage range of 2.7V to 5.5V and operates across the industrial temperature range of -40°C to 85°C.

Substiute Parts

P87C51RC2FN,112

NXP SemiconductorsIn Stock: 1078P87C51RC2FN,112 Datasheet

Current PartRFQ

AT89S51-24PU

Microchip TechnologyIn Stock: 11094AT89S51-24PU Datasheet

MFR RecommendedRFQ

DS87C520-MCL+

Analog Devices Inc./Maxim IntegratedIn Stock: 2458DS87C520-MCL+ Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution for the P87C51RC2FN,112 is determined by the following critical parameters:

• Core Processor Architecture: Must be 8051-compatible to ensure instruction set compatibility
• Package Type: Must be 40-DIP to maintain PCB layout compatibility
• Number of I/O Pins: Must provide 32 I/O pins for circuit interface compatibility
• Program Memory Type: OTP memory is preferred for direct replacement; FLASH memory represents a functional alternative with reprogrammability advantages
• Operating Temperature Range: Must support -40°C to 85°C for industrial applications
• Supply Voltage Range: Must accommodate the 2.7V to 5.5V range or a subset thereof

Two substitute parts are identified based on these criteria:

1. AT89S51-24PU (Microchip Technology): 8051-compatible with FLASH memory, lower speed (24MHz), reduced program memory (4KB), and narrower voltage range (4V ~ 5.5V)
2. DS87C520-MCL+ (Analog Devices Inc./Maxim Integrated): 8051-compatible with OTP memory, matching speed (33MHz), reduced program memory (16KB), and narrower voltage range (4.5V ~ 5.5V)

Parameter Comparison

Engineering Selection Recommendations

DS87C520-MCL+ (Primary Substitute)

The DS87C520-MCL+ is the preferred substitute for direct replacement applications. It maintains the same 8051 core architecture, 33MHz operating frequency, and OTP program memory type. The 16KB program memory capacity accommodates most applications originally designed for 32KB, provided firmware optimization is applied. The device supports the full industrial temperature range (-40°C to 85°C) and includes enhanced connectivity features (EBI/EMI, SIO, UART/USART) with power-fail reset capability. The narrower supply voltage range (4.5V ~ 5.5V) requires verification against the original circuit design. Both devices maintain ROHS3 compliance and identical package geometry.

AT89S51-24PU (Alternative Substitute)

The AT89S51-24PU serves as an alternative for applications with reduced program memory requirements (4KB maximum). The FLASH memory type enables field reprogrammability, eliminating the need for OTP device replacement during development and prototyping phases. The 24MHz operating frequency is lower than the original specification and must be evaluated against timing-critical firmware requirements. The reduced RAM capacity (128 bytes versus 512 bytes) and narrower supply voltage range (4V ~ 5.5V) require circuit design verification. This device maintains full industrial temperature range support (-40°C to 85°C) and ROHS3 compliance.

Frequently Asked Questions (FAQ)

Q: Can the AT89S51-24PU replace the P87C51RC2FN,112 in all applications?

A: The AT89S51-24PU is functionally compatible at the 8051 instruction set level but has significant limitations. The 4KB program memory is substantially reduced from 32KB, the 24MHz speed is lower than 33MHz, and RAM is reduced from 512 bytes to 128 bytes. Applications must be evaluated for these constraints. The FLASH memory type enables reprogrammability, which may be advantageous for development but differs from OTP operation.

Q: What are the voltage supply considerations when substituting?

A: The original P87C51RC2FN,112 operates from 2.7V to 5.5V. The DS87C520-MCL+ requires 4.5V to 5.5V, and the AT89S51-24PU requires 4V to 5.5V. If the original circuit operates below 4V, neither substitute is directly compatible without circuit modification. Verify the actual supply voltage in the target application before selection.

Q: Is the 40-DIP package identical across all three devices?

A: All three devices use the 40-DIP package with 0.600" (15.24mm) body dimensions, ensuring identical PCB footprint and pin spacing. No layout modifications are required for package compatibility.

Q: How does the operating temperature range affect substitution?

A: The P87C51RC2FN,112 and AT89S51-24PU both support -40°C to 85°C. The DS87C520-MCL+ operates only from 0°C to 70°C, which excludes it from applications requiring the full industrial temperature range below 0°C or above 70°C. Verify the target operating environment before selection.

Q: What is the significance of OTP versus FLASH memory?

A: OTP (One-Time Programmable) memory is programmed once during manufacturing and cannot be reprogrammed. FLASH memory can be erased and reprogrammed multiple times. The P87C51RC2FN,112 and DS87C520-MCL+ use OTP; the AT89S51-24PU uses FLASH. For production devices, OTP is standard. For development and prototyping, FLASH offers flexibility.

Q: Are there connectivity differences between the substitutes?

A: The P87C51RC2FN,112 includes EBI/EMI and UART/USART connectivity with POR, PWM, and WDT peripherals. The DS87C520-MCL+ adds SIO connectivity and power-fail reset capability. The AT89S51-24PU provides only UART/USART and WDT. Applications requiring EBI/EMI or PWM functionality must use the DS87C520-MCL+ or verify that the AT89S51-24PU's reduced peripheral set is sufficient.