AT80C31X2-SLSUM Equivalent & Substitute Parts

Part Overview

The AT80C31X2-SLSUM is an 8-bit ROMless microcontroller from Microchip Technology's 80C series, designed for embedded applications requiring external program memory. This device operates at 40/20MHz with 32 I/O pins and 128 x 8 bytes of RAM, housed in a 44-PLCC surface mount package. The part is currently obsolete, making identification of compatible substitutes essential for ongoing system support and new designs requiring equivalent functionality.

Substiute Parts

AT80C31X2-SLSUM

Microchip TechnologyIn Stock: 2386AT80C31X2-SLSUM Datasheet

Current PartRFQ

AT80C51RD2-SLSUM

Microchip TechnologyIn Stock: 1281AT80C51RD2-SLSUM Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

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

• Core Processor Architecture: Must be 80C51-based to maintain instruction set compatibility
• Core Size: Must remain 8-Bit
• Program Memory Type: Must be ROMless to match external memory configuration requirements
• Package / Case: Must be 44-LCC (J-Lead) for PCB compatibility
• Mounting Type: Must be Surface Mount
• I/O Count: Must provide minimum 32 I/O pins
• Operating Temperature Range: Must support -40°C ~ 85°C
• RoHS Compliance: Must maintain ROHS3 Compliant status

The AT80C51RD2-SLSUM qualifies as a direct substitute based on these parameters. While it introduces enhanced features (PWM, WDT peripherals, increased RAM to 1K x 8, and extended voltage range to 2.7V ~ 5.5V), these additions do not compromise compatibility and provide functional improvements for modern applications.

Parameter Comparison

Engineering Selection Recommendations

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

Product Status: The AT80C31X2-SLSUM is obsolete with limited inventory availability. The AT80C51RD2-SLSUM maintains active product status with established supply channels, ensuring long-term availability for production and support applications.

Compliance & Certifications: Both parts maintain ROHS3 Compliant and REACH Unaffected status, meeting current regulatory requirements. Both share identical ECCN (3A991A2) and HTSUS (8542.31.0001) classifications.

Functional Compatibility: The substitute maintains full 80C51 instruction set compatibility, identical I/O count, matching package geometry, and equivalent operating temperature range. The enhanced RAM capacity (1K x 8 versus 128 x 8) and extended voltage range (2.7V ~ 5.5V versus 4.5V ~ 5.5V) provide design flexibility without requiring firmware modifications.

Supply Chain: The AT80C51RD2-SLSUM is available in higher quantities with established distribution, reducing procurement risk compared to the obsolete main part.

Frequently Asked Questions (FAQ)

Q: Can the AT80C51RD2-SLSUM directly replace the AT80C31X2-SLSUM without PCB modifications?

A: Yes. Both devices use identical 44-LCC (J-Lead) packaging with matching pin configurations and I/O assignments. No PCB layout changes are required for pin-to-pin substitution.

Q: What is the difference in RAM capacity, and does it affect compatibility?

A: The AT80C31X2-SLSUM provides 128 x 8 bytes of RAM, while the AT80C51RD2-SLSUM provides 1K x 8 bytes. The increased RAM in the substitute is backward compatible; existing firmware requiring 128 bytes will function without modification. Additional RAM capacity enables enhanced functionality if needed.

Q: Does the extended voltage range of the AT80C51RD2-SLSUM (2.7V ~ 5.5V) affect system design?

A: No. The substitute's extended lower voltage limit (2.7V versus 4.5V) is a superset of the original specification. Systems designed for 4.5V ~ 5.5V operation remain fully compatible. The extended range provides flexibility for low-power applications if desired.

Q: Are the peripheral differences (PWM, WDT in the substitute) relevant for substitution?

A: The additional peripherals in the AT80C51RD2-SLSUM (PWM, WDT) are enhancements that do not interfere with existing firmware. Designs not utilizing these features will operate identically to the original part. Designs requiring these features gain additional capability.

Q: What is the impact of the speed specification difference (40/20MHz versus 40MHz)?

A: The AT80C31X2-SLSUM supports dual-speed operation (40MHz and 20MHz modes). The AT80C51RD2-SLSUM operates at 40MHz. Systems designed for 40MHz operation are fully compatible. Applications requiring 20MHz operation must verify that 40MHz operation meets timing requirements or implement software-based clock division if necessary.

Q: Are both parts RoHS3 compliant?

A: Yes. Both the AT80C31X2-SLSUM and AT80C51RD2-SLSUM are ROHS3 Compliant, meeting current environmental and regulatory standards.