AT89C4051-24SC Equivalent & Substitute Parts

Part Overview

The AT89C4051-24SC is an 8-bit microcontroller from Microchip Technology's 89C series, featuring 4KB FLASH program memory, 128 bytes of RAM, and 15 I/O pins. Designed for embedded applications requiring low-cost 8051-compatible processing, this device operates at 24MHz with integrated UART/USART connectivity and brown-out detection.

The AT89C4051-24SC is classified as obsolete. Locating equivalent substitute parts is necessary to maintain design continuity, ensure supply chain availability, and support legacy system maintenance or redesigns requiring active product alternatives.

Substiute Parts

AT89C4051-24SC

Microchip TechnologyIn Stock: 1342AT89C4051-24SC Datasheet

Current PartRFQ

AT89C4051-24SU

Microchip TechnologyIn Stock: 9889AT89C4051-24SU Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the AT89C4051-24SC is determined by strict equivalence across the following critical parameters:

• Core Architecture: 8051-compatible processor
• Memory Configuration: 4KB FLASH program memory, 128 bytes RAM
• Clock Speed: 24MHz operation
• I/O Count: 15 I/O pins
• Supply Voltage: 4V to 6V operating range
• Package: 20-SOIC form factor with identical pin pitch and dimensions
• Connectivity: UART/USART interface
• Integrated Peripherals: Brown-out detection, LED support, Power-On Reset

The AT89C4051-24SU qualifies as a direct substitute based on identical electrical specifications, core functionality, and mechanical compatibility. Differences in product status, operating temperature range, RoHS compliance, and packaging format (tube vs. unspecified) do not affect functional interchangeability in applications designed for the AT89C4051-24SC.

Parameter Comparison

Engineering Selection Recommendations

The AT89C4051-24SU is the direct functional equivalent of the AT89C4051-24SC. Selection between these parts should be based on the following factors:

Product Availability: The AT89C4051-24SC is obsolete with limited inventory. The AT89C4051-24SU is active with significantly higher stock availability (9879 pcs vs. 1313 pcs), making it the preferred choice for new designs and ongoing production.

Compliance Requirements: The AT89C4051-24SU meets ROHS3 compliance, whereas the AT89C4051-24SC is non-compliant. Applications subject to RoHS regulations must use the AT89C4051-24SU.

Operating Temperature Range: The AT89C4051-24SU supports -40°C to 85°C, compared to 0°C to 70°C for the AT89C4051-24SC. Applications requiring extended temperature operation must use the AT89C4051-24SU.

Moisture Sensitivity: The AT89C4051-24SU has MSL 3 (168 hours) versus MSL 2 (1 year) for the AT89C4051-24SC. Storage and handling procedures must reflect the respective moisture sensitivity classifications.

Pin Compatibility: Both devices use identical 20-SOIC packaging with matching pin assignments, enabling direct PCB-level substitution without layout modifications.

Frequently Asked Questions (FAQ)

Q: Can the AT89C4051-24SU replace the AT89C4051-24SC in existing designs?

A: Yes. Both devices share identical core architecture, memory configuration, clock speed, I/O count, supply voltage range, and 20-SOIC package. Pin-for-pin compatibility is complete. No circuit modifications are required.

Q: What is the difference between the AT89C4051-24SC and AT89C4051-24SU?

A: The primary differences are product status (obsolete vs. active), operating temperature range (0°C–70°C vs. -40°C–85°C), RoHS compliance (non-compliant vs. ROHS3 compliant), moisture sensitivity level (MSL 2 vs. MSL 3), and packaging format (unspecified vs. tube). Electrical and functional specifications are identical.

Q: Are there any circuit design changes needed when switching from AT89C4051-24SC to AT89C4051-24SU?

A: No circuit design changes are required. The devices are electrically and functionally equivalent. However, if the original design operated within the 0°C–70°C temperature range, the extended -40°C–85°C capability of the AT89C4051-24SU may allow operation in wider environmental conditions.

Q: Does the AT89C4051-24SU meet RoHS requirements?

A: Yes. The AT89C4051-24SU is ROHS3 compliant. The AT89C4051-24SC is not RoHS compliant. Applications requiring RoHS compliance must use the AT89C4051-24SU.

Q: What is the moisture sensitivity difference between these parts?

A: The AT89C4051-24SC has MSL 2 (1-year shelf life in dry conditions), while the AT89C4051-24SU has MSL 3 (168-hour shelf life). MSL 3 requires more stringent moisture control during storage and handling. Consult packaging and storage guidelines for each part number.

Q: Is the 20-SOIC package identical for both parts?

A: Yes. Both the AT89C4051-24SC and AT89C4051-24SU use the 20-SOIC package with 0.295" width and 7.50mm body width. Pin pitch, spacing, and mechanical dimensions are identical, enabling direct PCB substitution.

Q: Which part should be selected for new designs?

A: The AT89C4051-24SU should be selected for new designs. It is an active product with higher availability, extended operating temperature range, and RoHS3 compliance. The AT89C4051-24SC is obsolete and should be used only for legacy system maintenance where supply permits.