P3500SA Equivalent & Substitute Parts

Part Overview

The P3500SA is a 320V off-state, 150A peak pulse TVS thyristor manufactured by Littelfuse Inc. in the SIDACtor® series, housed in a DO-214AA (SMB) surface mount package. This component is classified as obsolete, making identification of equivalent and substitute parts essential for ongoing design support and procurement continuity. The part's primary function is transient voltage suppression in electronic circuits requiring high current handling capability.

Substiute Parts

P3500SA

Littelfuse Inc.In Stock: 10476P3500SA Datasheet

Current PartRFQ

P3500SALRP

Littelfuse Inc.In Stock: 10202P3500SALRP Datasheet

DirectRFQ

SMTPA270

STMicroelectronicsIn Stock: 4219SMTPA270 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the P3500SA are identified based on the following critical parameters that determine functional equivalence:

Primary Matching Criteria:

• Voltage - Off State: 320V (exact match required for circuit protection threshold)
• Current - Peak Pulse (8/20µs): 150A (exact match required for transient suppression capacity)
• Package / Case: DO-214AA, SMB (mechanical and thermal compatibility)
• Mounting Type: Surface Mount (PCB assembly compatibility)
• Number of Elements: 1 (functional architecture)

Secondary Compatibility Factors:

• Voltage - Breakover: 400V nominal (defines trigger threshold)
• Voltage - On State: 4V (forward voltage drop during conduction)
• Current - Hold (Ih): 150mA (minimum holding current)

Substitutes are grouped into two categories: direct manufacturer equivalents and manufacturer-recommended alternatives with minor parameter variations.

Parameter Comparison

Engineering Selection Recommendations

P3500SALRP (Direct Littelfuse Equivalent)

The P3500SALRP is the primary substitute for the obsolete P3500SA. Both parts share identical electrical specifications across all critical parameters: 320V off-state voltage, 400V breakover voltage, 150A peak pulse current (8/20µs), and 150mA holding current. The P3500SALRP maintains active product status and is available in Cut Tape and Digi-Reel packaging formats. The part achieves ROHS3 compliance, addressing regulatory requirements that the original P3500SA does not meet. Capacitance variation (35pF vs. 30pF) falls within acceptable tolerance for TVS thyristor applications. This part is the recommended direct replacement for new designs and existing inventory replenishment.

SMTPA270 (STMicroelectronics Alternative)

The SMTPA270 represents a manufacturer-recommended alternative from STMicroelectronics within the SMP/TRISIL™ series. This part maintains the 150A peak pulse current specification and identical package form factor (DO-214AA, SMB). The SMTPA270 operates at a lower off-state voltage of 270V with a correspondingly lower breakover voltage of 360V, representing a 50V reduction in both parameters. This voltage differential positions the SMTPA270 for applications requiring lower voltage suppression thresholds. The part achieves ROHS3 compliance and is available in Tape & Reel packaging. Selection of this alternative requires circuit-level validation to confirm compatibility with the reduced voltage ratings.

Frequently Asked Questions (FAQ)

Q: Can P3500SALRP be used as a direct drop-in replacement for P3500SA?

A: Yes. The P3500SALRP is electrically and mechanically identical to the P3500SA across all critical parameters: off-state voltage (320V), breakover voltage (400V), peak pulse current (150A), holding current (150mA), and package form factor (DO-214AA, SMB). The minor capacitance increase (35pF vs. 30pF) does not affect functional compatibility. The P3500SALRP is the recommended replacement due to active product status and improved regulatory compliance.

Q: What is the primary difference between P3500SALRP and SMTPA270?

A: The primary difference is the off-state voltage rating. P3500SALRP maintains 320V off-state voltage matching the original P3500SA, while SMTPA270 operates at 270V off-state voltage. Both parts share identical 150A peak pulse current capacity and DO-214AA package specifications. The voltage difference makes SMTPA270 suitable for lower-voltage protection circuits but requires circuit validation before substitution.

Q: Are there packaging differences between these substitutes?

A: P3500SALRP is available in Cut Tape (CT) and Digi-Reel® formats. SMTPA270 is supplied in Tape & Reel (TR) format. All three parts use the same DO-214AA (SMB) surface mount package, ensuring mechanical compatibility with existing PCB layouts. Packaging format selection depends on assembly process requirements and procurement volume.

Q: Do all substitute parts meet RoHS compliance?

A: The original P3500SA is RoHS non-compliant. Both P3500SALRP and SMTPA270 achieve ROHS3 compliance, meeting current regulatory requirements for electronic component procurement in most markets.

Q: What is the capacitance variation across these parts, and does it matter?

A: Capacitance values are P3500SA (30pF), P3500SALRP (35pF), and SMTPA270 (25pF). For TVS thyristor applications, capacitance variations within this range do not significantly impact transient suppression performance. The capacitance specification reflects parasitic junction capacitance and does not affect the primary voltage suppression or current handling functions.