AT80C51RA2-SLSUL Equivalent & Substitute Parts

Part Overview

The AT80C51RA2-SLSUL is an 8-bit microcontroller from Microchip Technology's 80C series, featuring ROMless architecture with 512 x 8 bytes of RAM. This device operates at 30/20MHz with a supply voltage range of 2.7V to 5.5V and includes integrated peripherals such as UART/USART connectivity, Power-On Reset (POR), Pulse Width Modulation (PWM), and Watchdog Timer (WDT) functionality. The part is mounted in a 44-PLCC surface mount package with 32 I/O pins.

The AT80C51RA2-SLSUL is classified as obsolete. Locating equivalent or substitute components becomes necessary when original inventory is depleted or when design requirements necessitate active production status and enhanced specifications.

Key Parameters

Parameter	Value
Core Processor	80C51
Core Size	8-Bit
Speed	30/20MHz
Program Memory Type	ROMless
RAM Size	512 x 8
Voltage Supply (Vcc/Vdd)	2.7V ~ 5.5V
Number of I/O	32
Connectivity	UART/USART
Peripherals	POR, PWM, WDT
Operating Temperature	-40°C ~ 85°C (TA)
Package / Case	44-LCC (J-Lead)
Mounting Type	Surface Mount
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitution of the AT80C51RA2-SLSUL is determined by strict adherence to the following critical parameters:

Core Architecture Compatibility: The substitute must maintain the 80C51 core processor and 8-bit architecture to ensure instruction set compatibility and firmware portability.

Package Compatibility: The substitute must use the 44-LCC (J-Lead) surface mount package with identical pinout and mechanical dimensions (16.6x16.6mm) to enable direct board-level replacement without layout modifications.

Voltage Supply Range: The substitute must support the 2.7V to 5.5V supply voltage range to maintain compatibility with existing power distribution designs.

Memory Architecture: The substitute must retain ROMless program memory type and maintain or exceed the 512 x 8 RAM capacity to support existing firmware requirements.

Peripheral Set: The substitute must include UART/USART connectivity, POR, PWM, and WDT functionality to preserve system-level integration.

Operating Temperature Range: The substitute must support the -40°C to 85°C operating temperature range to maintain thermal compatibility.

The AT80C51RD2-SLSUM qualifies as a manufacturer-recommended substitute based on these criteria.

Parameter Comparison

Parameter	AT80C51RA2-SLSUL (Main Part)	AT80C51RD2-SLSUM (Substitute)
Manufacturer	Microchip Technology	Microchip Technology
Core Processor	80C51	80C51
Core Size	8-Bit	8-Bit
Speed	30/20MHz	40MHz
Program Memory Type	ROMless	ROMless
RAM Size	512 x 8	1K x 8
Voltage Supply (Vcc/Vdd)	2.7V ~ 5.5V	2.7V ~ 5.5V
Number of I/O	32	32
Connectivity	UART/USART	UART/USART
Peripherals	POR, PWM, WDT	POR, PWM, WDT
Operating Temperature	-40°C ~ 85°C (TA)	-40°C ~ 85°C (TA)
Package / Case	44-LCC (J-Lead)	44-LCC (J-Lead)
Mounting Type	Surface Mount	Surface Mount
Product Status	Obsolete	Active
RoHS Status	ROHS3 Compliant	ROHS3 Compliant
REACH Status	REACH Unaffected	REACH Unaffected

Engineering Selection Recommendations

The AT80C51RD2-SLSUM is the manufacturer-recommended substitute for the AT80C51RA2-SLSUL. This substitution is supported by the following factors:

Product Status: The AT80C51RD2-SLSUM maintains active production status, ensuring long-term availability and supply chain continuity compared to the obsolete AT80C51RA2-SLSUL.

Regulatory Compliance: Both parts maintain ROHS3 compliance and REACH unaffected status, preserving environmental and regulatory requirements across design lifecycles.

Performance Enhancement: The AT80C51RD2-SLSUM operates at 40MHz compared to the 30/20MHz of the original part, providing increased processing capability while maintaining full backward compatibility with the 80C51 instruction set.

Memory Expansion: The substitute provides 1K x 8 RAM compared to 512 x 8 in the original part, offering doubled RAM capacity for enhanced application flexibility without architectural changes.

Electrical Compatibility: Identical voltage supply range (2.7V ~ 5.5V), operating temperature range (-40°C ~ 85°C), and peripheral configuration ensure direct functional replacement.

Frequently Asked Questions (FAQ)

Q: Can the AT80C51RD2-SLSUM be used as a direct replacement for the AT80C51RA2-SLSUL without PCB modifications?

A: Yes. Both parts use the 44-LCC (J-Lead) package with identical pinout and mechanical dimensions (16.6x16.6mm). Direct board-level substitution is possible without layout changes.

Q: What are the key differences between these two parts?

A: The AT80C51RD2-SLSUM operates at 40MHz versus 30/20MHz for the AT80C51RA2-SLSUL, and provides 1K x 8 RAM versus 512 x 8. Both maintain identical core architecture, voltage supply range, I/O count, and peripheral configuration.

Q: Is firmware compatibility maintained between these parts?

A: Yes. Both parts use the 80C51 core processor and instruction set. Existing firmware requires no modification for operation on the AT80C51RD2-SLSUM.

Q: What is the significance of the AT80C51RA2-SLSUL being classified as obsolete?

A: Obsolete status indicates the part is no longer in active production. The AT80C51RD2-SLSUM is the active production alternative, ensuring availability for new designs and ongoing supply for existing applications.

Q: Are there any thermal or environmental considerations when substituting these parts?

A: Both parts operate across the identical temperature range (-40°C ~ 85°C) and maintain the same RoHS3 and REACH compliance status. No thermal or environmental design modifications are required.

Q: Does the increased RAM capacity of the AT80C51RD2-SLSUM affect compatibility?

A: No. The increased RAM (1K x 8 versus 512 x 8) is a superset of the original specification. Existing firmware designed for 512 x 8 RAM operates without modification on the substitute part.

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