AT89C55WD-24PI Equivalent & Substitute Parts

Part Overview

The AT89C55WD-24PI is an 8051-based 8-bit microcontroller manufactured by Microchip Technology, featuring 20KB of FLASH program memory and operating at 24MHz. This part is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and production continuity. The 40-PDIP package and core electrical specifications define the substitution criteria for compatible alternatives.

Substiute Parts

AT89C55WD-24PI

Microchip TechnologyIn Stock: 1281AT89C55WD-24PI Datasheet

Current PartRFQ

AT89C55WD-24PU

Microchip TechnologyIn Stock: 5611AT89C55WD-24PU Datasheet

DirectRFQ

DS89C430-MNG+

Analog Devices Inc./Maxim IntegratedIn Stock: 20134DS89C430-MNG+ Datasheet

MFR RecommendedRFQ

DS89C430-MNL+

Analog Devices Inc./Maxim IntegratedIn Stock: 1165DS89C430-MNL+ Datasheet

MFR RecommendedRFQ

DS89C450-MNL+

Analog Devices Inc./Maxim IntegratedIn Stock: 1779DS89C450-MNL+ Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution for the AT89C55WD-24PI is determined by compatibility across the following critical parameters: 8051 core processor architecture, 8-bit core size, FLASH program memory type, 40-PDIP package footprint, 4.5V to 5.5V supply voltage range, -40°C to 85°C operating temperature range, 32 I/O pins, and UART/USART connectivity.

Substitute parts are grouped into two categories:

Direct Equivalent (Identical Specifications): AT89C55WD-24PU maintains all electrical and mechanical specifications of the main part, differing only in packaging format (Tube vs. standard packaging) and product status (Active vs. Obsolete).

Functional Alternatives (Compatible with Design Modifications): DS89C430-MNG+, DS89C430-MNL+, and DS89C450-MNL+ share the 8051 core, 40-PDIP package, voltage range, temperature range, and I/O count. These parts differ in program memory size, operating speed, RAM capacity, oscillator type, and peripheral configuration, requiring design review for memory and speed compatibility.

Parameter Comparison

Engineering Selection Recommendations

AT89C55WD-24PU is the primary direct equivalent for AT89C55WD-24PI. Both parts maintain identical electrical specifications, package footprint, and pin configuration. AT89C55WD-24PU is classified as Active product status with ROHS3 compliance, providing superior long-term availability and regulatory alignment compared to the obsolete, non-compliant main part.

DS89C430-MNL+ is suitable for designs requiring higher operating speed (33MHz vs. 24MHz) and expanded RAM capacity (1K x 8 vs. 256 x 8). This part is Active with ROHS3 compliance. Program memory is reduced to 16KB, requiring verification that application code fits within this constraint. External oscillator requirement differs from the internal oscillator of the main part.

DS89C450-MNL+ provides the highest program memory capacity (64KB) among substitutes, supporting applications with larger code footprints. Operating speed is 33MHz with 1K x 8 RAM. This part is Active with ROHS3 compliance. External oscillator requirement and expanded connectivity (EBI/EMI, SIO) must be evaluated for circuit compatibility.

DS89C430-MNG+ is classified as Obsolete and should be avoided for new designs despite technical compatibility. Preference should be given to Active parts with current product status.

Frequently Asked Questions (FAQ)

Q: Can AT89C55WD-24PU directly replace AT89C55WD-24PI without circuit modifications?

A: Yes. AT89C55WD-24PU is a direct equivalent with identical electrical specifications, pin configuration, and 40-PDIP package. The only differences are packaging format and product status. No circuit modifications are required.

Q: What are the key differences between AT89C55WD-24PI and DS89C430-MNL+?

A: Program memory is reduced from 20KB to 16KB. Operating speed increases from 24MHz to 33MHz. RAM expands from 256 x 8 to 1K x 8. Oscillator type changes from internal to external, requiring external crystal or oscillator circuit. Additional peripherals (Power-Fail Reset) and connectivity options (EBI/EMI, SIO) are added. Application code must be verified to fit within 16KB memory.

Q: Is DS89C450-MNL+ compatible with designs using AT89C55WD-24PI?

A: DS89C450-MNL+ shares the same 8051 core, 40-PDIP package, voltage range, temperature range, and I/O count. However, program memory is increased to 64KB, operating speed is 33MHz, and oscillator type is external. These differences require design review to confirm code compatibility and circuit modifications for external oscillator support.

Q: Why does AT89C55WD-24PI show RoHS non-compliant status?

A: AT89C55WD-24PI is classified as obsolete. Substitute parts AT89C55WD-24PU, DS89C430-MNL+, and DS89C450-MNL+ are all ROHS3 compliant, meeting current regulatory requirements for new designs and production.

Q: What is the impact of changing from internal to external oscillator?

A: DS89C430-MNG+, DS89C430-MNL+, and DS89C450-MNL+ require external oscillator circuits, whereas AT89C55WD-24PI uses an internal oscillator. External oscillator designs require additional components (crystal or oscillator module) and PCB layout considerations. Timing accuracy and frequency stability may differ based on external component selection.

Q: Can I use DS89C430-MNG+ for new production?

A: DS89C430-MNG+ is classified as obsolete. For new designs and ongoing production, use Active parts: AT89C55WD-24PU, DS89C430-MNL+, or DS89C450-MNL+. Active product status ensures long-term availability and manufacturer support.