SMDA24 Equivalent & Substitute Parts Reference

Part Overview

The SMDA24 is a 24V Transient Voltage Suppressor (TVS) diode manufactured by Microchip Technology, designed for general-purpose overvoltage protection in surface-mount applications. This unidirectional 4-channel TVS array operates with a 43V maximum clamping voltage and 5A peak pulse current rating, housed in an 8-SOIC package.

The original Microchip SMDA24 has been discontinued at DiGi Electronics, necessitating identification of functionally equivalent alternatives. Active substitute options are available from Microchip Technology, SMC Diode Solutions, and Semtech Corporation, each offering different packaging configurations and compliance certifications.

Substiute Parts

SMDA24

Microchip TechnologyIn Stock: 1137SMDA24 Datasheet

Current PartRFQ

SMDA24E3/TR7

Microchip TechnologyIn Stock: 5643SMDA24E3/TR7 Datasheet

DirectRFQ

SMDB24/TR7

Microchip TechnologyIn Stock: 1354SMDB24/TR7 Datasheet

SimilarRFQ

SMDA24

SMC Diode SolutionsIn Stock: 6229SMDA24 Datasheet

SimilarRFQ

SMDA24.TBT

Semtech CorporationIn Stock: 2168SMDA24.TBT Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the SMDA24 is determined by strict equivalence across the following critical parameters:

Mandatory Matching Parameters:

• Voltage - Reverse Standoff (Typ): 24V
• Voltage - Breakdown (Min): 26.7V
• Unidirectional Channels: 4
• Package / Case: 8-SOIC (0.154", 3.90mm Width)
• Mounting Type: Surface Mount
• Type: Zener

Allowable Variation Parameters:

• Voltage - Clamping (Max) @ Ipp: 43V to 55V (higher clamping voltage provides additional margin)
• Current - Peak Pulse: 1A to 5A (lower current rating represents reduced surge capacity)
• Capacitance @ 1MHz: 60pF to 90pF (minor variation acceptable for general-purpose applications)
• Operating Temperature: -55°C to 125°C or -55°C to 150°C (both ranges acceptable)
• Packaging Format: Tape & Reel (TR) or Cut Tape (CT) (both are standard distribution methods)
• RoHS Status: RoHS3 Compliant or RoHS non-compliant (compliance status does not affect electrical function)

Substitute Parts Identified:

1. SMDA24E3/TR7 (Microchip Technology) - Direct equivalent with enhanced compliance
2. SMDB24/TR7 (Microchip Technology) - Electrical equivalent with different packaging
3. SMDA24 (SMC Diode Solutions) - Functional equivalent with reduced current rating
4. SMDA24.TBT (Semtech Corporation) - Functional equivalent with higher clamping voltage

Parameter Comparison

Engineering Selection Recommendations

Primary Recommendation: SMDA24E3/TR7 (Microchip Technology)

The SMDA24E3/TR7 is the direct functional and electrical equivalent of the discontinued SMDA24. This part maintains identical electrical specifications across all critical parameters: 24V reverse standoff voltage, 26.7V minimum breakdown voltage, 43V maximum clamping voltage, and 5A peak pulse current. The SMDA24E3/TR7 is currently in active production status with substantial inventory availability (5534 units). This part achieves ROHS3 compliance, meeting modern regulatory requirements. The Tape & Reel packaging format is standard for automated assembly processes.

Secondary Recommendation: SMDB24/TR7 (Microchip Technology)

The SMDB24/TR7 provides electrical equivalence with identical voltage and current specifications. This part remains in active production with 1267 units available. The Cut Tape packaging format is suitable for lower-volume or manual assembly operations. Note that this part does not achieve ROHS3 compliance.

Alternative Recommendation: SMDA24.TBT (Semtech Corporation)

The SMDA24.TBT offers functional equivalence with a higher clamping voltage specification (55V maximum versus 43V). This higher clamping voltage provides additional transient suppression margin. The part achieves ROHS3 compliance and maintains the 5A peak pulse current rating. Operating temperature range is reduced to -55°C to 125°C. Capacitance is lower at 60pF versus 90pF. This part is suitable for applications requiring enhanced overvoltage protection margin.

Not Recommended: SMDA24 (SMC Diode Solutions)

While this part maintains voltage equivalence and ROHS3 compliance, the reduced peak pulse current rating (1A versus 5A) significantly limits surge handling capacity. This part is suitable only for applications with lower transient energy requirements.

Frequently Asked Questions (FAQ)

Q1: Can SMDA24E3/TR7 be used as a direct replacement for the discontinued SMDA24?

A: Yes. The SMDA24E3/TR7 is electrically and mechanically identical to the original SMDA24. Both parts feature 24V reverse standoff voltage, 26.7V minimum breakdown voltage, 43V maximum clamping voltage, 5A peak pulse current, and 8-SOIC packaging. The primary difference is that SMDA24E3/TR7 is supplied in Tape & Reel format and achieves ROHS3 compliance.

Q2: What is the difference between SMDA24E3/TR7 and SMDB24/TR7?

A: Both parts are manufactured by Microchip Technology and share identical electrical specifications. The primary difference is the base product designation (SMDA24 versus SMDB24). Both maintain 24V reverse standoff voltage, 43V clamping voltage, and 5A peak pulse current. SMDA24E3/TR7 achieves ROHS3 compliance while SMDB24/TR7 does not.

Q3: Why does SMDA24.TBT have a higher clamping voltage (55V) than the original SMDA24 (43V)?

A: The SMDA24.TBT is manufactured by Semtech Corporation and represents a different design variant within the same voltage class. The higher 55V clamping voltage provides additional protection margin during transient suppression events. This part is suitable for applications requiring enhanced overvoltage protection.

Q4: Can the SMC Diode Solutions SMDA24 be used in high-current surge applications?

A: No. The SMC Diode Solutions SMDA24 is rated for only 1A peak pulse current, compared to 5A for the original Microchip SMDA24. This reduced current rating limits its use to applications with lower transient energy requirements. For applications requiring 5A surge handling, use SMDA24E3/TR7, SMDB24/TR7, or SMDA24.TBT.

Q5: Are all substitute parts compatible with the same PCB footprint?

A: Yes. All substitute parts use the 8-SOIC package with 0.154" width (3.90mm). PCB footprints are mechanically identical and directly compatible.

Q6: What is the significance of Tape & Reel versus Cut Tape packaging?

A: Tape & Reel packaging is optimized for high-volume automated assembly processes using pick-and-place equipment. Cut Tape packaging is suitable for lower-volume production or manual assembly. Both formats contain the same component; the difference is in distribution and handling method.

Q7: Does RoHS3 compliance affect electrical performance?

A: No. RoHS3 compliance is a regulatory certification indicating the absence of restricted substances in the component. It does not alter electrical specifications, performance characteristics, or functional equivalence. Both RoHS3-compliant and non-compliant parts perform identically in circuit applications.

Q8: What is the operating temperature difference between substitute parts?

A: The original Microchip SMDA24 and SMDA24E3/TR7 operate from -55°C to 150°C. The SMC Diode Solutions SMDA24 and Semtech SMDA24.TBT operate from -55°C to 125°C. For applications requiring operation above 125°C, use Microchip parts.

Q9: How does capacitance variation (60pF to 90pF) affect circuit performance?

A: Capacitance variation is minor and acceptable for general-purpose TVS applications. The 60pF capacitance of SMDA24.TBT versus 90pF of other parts may provide slightly improved high-frequency performance in sensitive circuits, but both values are within acceptable ranges for standard overvoltage protection applications.

Q10: Which substitute part offers the best overall compatibility?

A: SMDA24E3/TR7 offers the best overall compatibility. It maintains complete electrical equivalence with the original SMDA24, achieves ROHS3 compliance, is in active production with high inventory availability, and uses standard Tape & Reel packaging suitable for automated assembly.