SA20 Transient Voltage Suppressor (TVS) Diode - Equivalent & Substitute Parts

Part Overview

The SA20 is a unidirectional Zener-type transient voltage suppressor manufactured by Littelfuse Inc., designed for general-purpose overvoltage protection applications. This through-hole component operates across a temperature range of -55°C to 175°C and is housed in a DO-204AC (DO-15) axial package. The SA20 is classified as obsolete, making equivalent substitute parts necessary for ongoing design support and procurement.

Substiute Parts

SA20

Littelfuse Inc.In Stock: 890SA20 Datasheet

Current PartRFQ

SA20A

Fairchild SemiconductorIn Stock: 300483SA20A Datasheet

DirectRFQ

P5KE20A-AP

Micro Commercial CoIn Stock: 867P5KE20A-AP Datasheet

MFR RecommendedRFQ

SA20A-AP

Micro Commercial CoIn Stock: 1185SA20A-AP Datasheet

MFR RecommendedRFQ

SA20A-BP

Micro Commercial CoIn Stock: 816SA20A-BP Datasheet

MFR RecommendedRFQ

SA20A-TP

Micro Commercial CoIn Stock: 10279SA20A-TP Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the SA20 is determined by the following critical parameters:

• Reverse Standoff Voltage: 20V (nominal)
• Breakdown Voltage: minimum 21.02V to 22.2V range
• Clamping Voltage: 32.4V to 34.02V maximum
• Peak Pulse Current: 15.4A to 15.7A
• Peak Pulse Power: 500W
• Package: DO-204AC or DO-15 axial through-hole
• Unidirectional Zener configuration
• General-purpose application class

All substitute parts listed maintain these electrical specifications within acceptable tolerances and share identical mechanical compatibility with the original SA20 footprint.

Parameter Comparison

Engineering Selection Recommendations

For new designs and ongoing procurement, the Micro Commercial Co (MCC) variants SA20A-AP, SA20A-BP, and SA20A-TP are preferred substitutes due to active product status and REACH compliance certification. These parts maintain full electrical and mechanical compatibility with the original SA20 specification.

The SA20A-TP variant in Cut Tape (CT) packaging offers the highest inventory availability (10,214 pcs) and is suitable for automated assembly processes. The SA20A-AP and SA20A-BP variants in bulk packaging provide alternative sourcing options with comparable electrical performance.

The P5KE20A-AP from Micro Commercial Co is functionally equivalent with a slightly lower peak pulse current specification (15.4A versus 15.7A) and an extended lower operating temperature limit (-65°C versus -55°C), making it suitable for applications requiring enhanced cold-temperature performance.

The SA20A from Fairchild Semiconductor remains electrically compatible but shares obsolete status with the original SA20, limiting its suitability for long-term production support.

Frequently Asked Questions (FAQ)

Q: Can SA20A-TP be used in place of SA20 in existing designs? A: Yes. The SA20A-TP maintains identical reverse standoff voltage (20V), peak pulse power (500W), peak pulse current (15.7A), and DO-15 package compatibility. The clamping voltage specification (32.4V) is lower than the original SA20 (34.02V), which provides improved transient suppression performance.

Q: What is the difference between SA20A-AP, SA20A-BP, and SA20A-TP? A: These three Micro Commercial Co variants are electrically identical. The primary difference is packaging: SA20A-AP and SA20A-BP are supplied in bulk packaging, while SA20A-TP is supplied in cut tape (CT) format. Selection depends on assembly process requirements and inventory management preferences.

Q: Is P5KE20A-AP suitable for applications requiring the full -55°C to 175°C temperature range? A: The P5KE20A-AP supports -65°C to 175°C operation, which exceeds the original SA20 specification of -55°C to 175°C. It is suitable for all applications within the original temperature range and provides additional margin for cold-temperature environments.

Q: Are all substitute parts RoHS3 compliant? A: SA20A-TP is explicitly RoHS3 compliant. Compliance status for SA20A (Fairchild), P5KE20A-AP, SA20A-AP, and SA20A-BP is not specified in available documentation.

Q: What is the significance of the clamping voltage difference between SA20 (34.02V) and substitute parts (32.4V)? A: The lower clamping voltage in substitute parts (32.4V) indicates faster transient suppression at lower voltage levels, which is beneficial for circuit protection. This represents an improvement over the original specification and does not compromise compatibility.

Q: Can these parts be used interchangeably in PCB designs? A: Yes. All substitute parts use identical DO-15 axial through-hole package geometry, ensuring direct mechanical and electrical interchangeability in existing PCB layouts without design modification.