P4SMA540 Equivalent & Substitute Parts

Part Overview

The P4SMA540 is a unidirectional Transient Voltage Suppressor (TVS) diode manufactured by Littelfuse Inc., designed for general-purpose overvoltage protection applications. This component features a 486V reverse standoff voltage with a 777V maximum clamping voltage and 500mA peak pulse current capability in a surface-mount DO-214AC (SMA) package.

The P4SMA540 is classified as obsolete. Equivalent substitute parts are available to maintain design continuity and ensure supply chain reliability for applications requiring this voltage suppression specification.

Substiute Parts

P4SMA540

Littelfuse Inc.In Stock: 1194P4SMA540 Datasheet

Current PartRFQ

P4SMA540A

Littelfuse Inc.In Stock: 18490P4SMA540A Datasheet

MFR RecommendedRFQ

P4SMA540A

Littelfuse Inc.In Stock: 18490P4SMA540A Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the P4SMA540 is determined by the following critical electrical and mechanical parameters:

• Reverse Standoff Voltage (Typ): 486V — must remain constant
• Peak Pulse Current (10/1000µs): 500mA — must remain constant
• Power - Peak Pulse: 400W — must remain constant
• Package / Case: DO-214AC, SMA — must remain identical
• Mounting Type: Surface Mount — must remain identical
• Unidirectional Channels: 1 — must remain constant
• Operating Temperature Range: -65°C ~ 150°C (TJ) — must remain constant

The P4SMA540A qualifies as a direct substitute because it maintains all critical electrical parameters (reverse standoff voltage, peak pulse current, power rating, and operating temperature) and identical mechanical packaging. The difference in maximum clamping voltage (740V vs. 777V) represents a tighter clamping specification, which is acceptable for general-purpose protection applications where the original 777V specification is not a binding design constraint.

Parameter Comparison

Engineering Selection Recommendations

The P4SMA540A is the recommended substitute for the obsolete P4SMA540. Both components are manufactured by Littelfuse Inc. and maintain identical compliance certifications (ROHS3 Compliant, MSL 1). The P4SMA540A carries Active product status, ensuring continued availability and supply chain support.

Both parts are suitable for general-purpose transient voltage suppression applications requiring 486V reverse standoff protection with 500mA peak pulse current handling in surface-mount DO-214AC packaging. The P4SMA540A's lower maximum clamping voltage (740V vs. 777V) provides enhanced protection margins in applications where clamping voltage specification is not a critical design parameter.

Frequently Asked Questions (FAQ)

Q: Can the P4SMA540A be used as a direct replacement for the P4SMA540?

A: Yes. Both components share identical reverse standoff voltage (486V), peak pulse current (500mA), power rating (400W), operating temperature range (-65°C ~ 150°C), and DO-214AC surface-mount packaging. The P4SMA540A is the manufacturer-recommended substitute for the obsolete P4SMA540.

Q: What is the difference between the P4SMA540 and P4SMA540A?

A: The primary difference is the maximum clamping voltage specification: P4SMA540 specifies 777V, while P4SMA540A specifies 740V. Both maintain the same reverse standoff voltage and peak pulse current ratings. The P4SMA540A also carries Active product status, whereas the P4SMA540 is obsolete.

Q: Are there any package or mounting differences?

A: No. Both the P4SMA540 and P4SMA540A use identical DO-214AC (SMA) surface-mount packaging and mounting type. PCB layout and assembly processes require no modification.

Q: What compliance certifications apply to both parts?

A: Both components are ROHS3 Compliant with Moisture Sensitivity Level (MSL) 1 (Unlimited), indicating no moisture sensitivity restrictions during storage or handling.

Q: Why is the P4SMA540 classified as obsolete?

A: The P4SMA540 has been discontinued by the manufacturer. The P4SMA540A remains in active production and is the recommended alternative for new designs and replacement applications.