AT80C31X2-SLSUL Equivalent & Substitute Parts

Part Overview

The AT80C31X2-SLSUL is an 8-bit ROMless microcontroller from Microchip Technology's 80C series, designed for embedded applications requiring external program memory. This device operates at 30/20MHz with a 44-PLCC package and supports UART/USART connectivity with Power-On Reset functionality. The part is currently obsolete, making substitute identification critical for ongoing system support and new design implementations.

Key Parameters

Parameter	Value
Core Processor	80C51
Core Size	8-Bit
Speed	30/20MHz
Program Memory Type	ROMless
RAM Size	128 x 8
Voltage Supply (Vcc/Vdd)	2.7V ~ 5.5V
Number of I/O	32
Package	44-PLCC (16.6x16.6)
Operating Temperature	-40°C ~ 85°C (TA)
Mounting Type	Surface Mount

Substitute Part Grouping Explanation

Substitution for the AT80C31X2-SLSUL is determined by the following critical parameters:

Core processor compatibility (80C51 architecture)
ROMless program memory configuration
Identical voltage supply range (2.7V ~ 5.5V)
Matching I/O count (32 pins)
Compatible package form factor (44-PLCC)
Operating temperature range alignment (-40°C ~ 85°C)
Surface mount mounting type

The AT80C51RD2-SLSUM qualifies as a direct substitute based on these parameters. While it offers enhanced specifications (40MHz speed, 1K x 8 RAM, additional peripherals), it maintains full backward compatibility with the electrical and mechanical requirements of the original part.

Parameter Comparison

Parameter	AT80C31X2-SLSUL	AT80C51RD2-SLSUM	Compatibility
Core Processor	80C51	80C51	Identical
Core Size	8-Bit	8-Bit	Identical
Speed	30/20MHz	40MHz	Compatible (higher speed)
Program Memory Type	ROMless	ROMless	Identical
RAM Size	128 x 8	1K x 8	Compatible (larger capacity)
Voltage Supply (Vcc/Vdd)	2.7V ~ 5.5V	2.7V ~ 5.5V	Identical
Number of I/O	32	32	Identical
Package	44-PLCC (16.6x16.6)	44-PLCC (16.6x16.6)	Identical
Operating Temperature	-40°C ~ 85°C (TA)	-40°C ~ 85°C (TA)	Identical
Mounting Type	Surface Mount	Surface Mount	Identical
Connectivity	UART/USART	UART/USART	Identical
Peripherals	POR	POR, PWM, WDT	Compatible (enhanced features)
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	Identical
REACH Status	REACH Unaffected	REACH Unaffected	Identical

Engineering Selection Recommendations

The AT80C51RD2-SLSUM is the qualified substitute for the obsolete AT80C31X2-SLSUL. Selection is based on the following factors:

Both parts maintain ROHS3 compliance and REACH unaffected status, ensuring regulatory alignment
Identical electrical specifications (voltage supply, operating temperature, I/O configuration) guarantee direct pin-compatible replacement
Matching 44-PLCC package form factor and surface mount technology enable direct PCB integration without layout modifications
The substitute part is in active product status with confirmed inventory availability, providing supply chain continuity
Enhanced specifications (40MHz speed, 1K x 8 RAM, PWM and WDT peripherals) provide performance headroom without compromising backward compatibility
Both parts share identical ECCN and HTSUS classifications, maintaining export compliance consistency

Frequently Asked Questions (FAQ)

Q: Can the AT80C51RD2-SLSUM directly replace the AT80C31X2-SLSUL in existing designs?

A: Yes. Both parts share identical core processor architecture (80C51), voltage supply range (2.7V ~ 5.5V), I/O count (32), package form factor (44-PLCC), and operating temperature range (-40°C ~ 85°C). Pin-for-pin compatibility is maintained, allowing direct PCB substitution without design modifications.

Q: What are the key differences between these parts?

A: The AT80C51RD2-SLSUM offers three enhancements: maximum operating speed increased from 30/20MHz to 40MHz, internal RAM expanded from 128 x 8 to 1K x 8, and additional peripherals (PWM and WDT) compared to the original POR-only configuration. These are functional improvements that do not affect compatibility.

Q: Are there any compliance or certification differences?

A: No. Both parts maintain identical RoHS3 compliance, REACH unaffected status, and ECCN/HTSUS classifications. Regulatory and export requirements remain unchanged.

Q: What is the packaging difference between these parts?

A: The AT80C31X2-SLSUL uses standard packaging, while the AT80C51RD2-SLSUM is supplied in tube packaging. Both maintain the identical 44-PLCC (16.6x16.6) form factor and surface mount configuration. Packaging type does not affect electrical or mechanical compatibility.

Q: Why is the AT80C31X2-SLSUL obsolete?

A: The AT80C31X2-SLSUL is classified as obsolete by Microchip Technology. The AT80C51RD2-SLSUM is the active product continuation, offering equivalent functionality with enhanced specifications and ongoing manufacturer support.

Q: Are there any firmware or software modifications required for substitution?

A: No firmware modifications are required. The 80C51 core processor architecture is identical between both parts. Existing firmware compiled for the AT80C31X2-SLSUL will execute on the AT80C51RD2-SLSUM without modification.

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