CR3500SC Equivalent & Substitute Parts

Part Overview

The CR3500SC is a Transient Voltage Suppressor (TVS) thyristor manufactured by Littelfuse Inc., designed for overvoltage protection in surface-mount applications. This component operates at 320V off-state voltage with a peak pulse current rating of 250A (8/20µs). The CR3500SC is classified as obsolete, making identification of suitable substitute parts essential for ongoing system support and new design implementations.

Substiute Parts

CR3500SC

Littelfuse Inc.In Stock: 1277CR3500SC Datasheet

Current PartRFQ

P3500SCLRP

Littelfuse Inc.In Stock: 55207P3500SCLRP Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the CR3500SC is determined by electrical and mechanical compatibility across the following critical parameters:

Voltage ratings (breakover, off-state, and on-state) must remain within the same specification range to ensure proper overvoltage protection without nuisance triggering. Peak pulse current ratings determine the component's ability to suppress transient events; substitutes must meet or exceed the original specification. The holding current (Ih) establishes the minimum current required to maintain the thyristor in its conducting state. Package and mounting type must be identical to ensure PCB compatibility without redesign. Capacitance values affect high-frequency response characteristics.

The P3500SCLRP qualifies as a direct substitute based on matching voltage ratings (400V breakover, 320V off-state), identical package configuration (DO-214AA, SMB), and equivalent holding current (150mA). The substitute provides enhanced peak pulse current capability (400A at 8/20µs versus 250A), representing an upgrade in transient suppression capacity.

Parameter Comparison

Engineering Selection Recommendations

The P3500SCLRP is the qualified substitute for the obsolete CR3500SC. Both components share identical voltage ratings and package configurations, ensuring direct PCB compatibility. The P3500SCLRP maintains active product status with ROHS3 compliance, addressing regulatory requirements that may apply to new designs or system updates. The substitute's enhanced peak pulse current rating (400A versus 250A) provides additional transient suppression margin without compromising circuit performance. The minimal on-state voltage difference (4V versus 5V) and slight capacitance increase (65pF versus 60pF) remain within acceptable operating parameters for equivalent functionality.

Frequently Asked Questions (FAQ)

Q: Can the P3500SCLRP be used as a direct replacement for CR3500SC on existing PCBs?

A: Yes. Both components use the DO-214AA, SMB package with identical pinout and mounting footprint. No PCB modifications are required.

Q: What is the significance of the higher peak pulse current rating in the P3500SCLRP?

A: The P3500SCLRP's 400A peak pulse current (8/20µs) exceeds the CR3500SC's 250A rating. This provides enhanced transient suppression capability and greater safety margin during overvoltage events without affecting circuit operation.

Q: Are there compliance differences between these parts?

A: Yes. The CR3500SC is RoHS non-compliant, while the P3500SCLRP is ROHS3 compliant. For new designs or systems subject to RoHS regulations, the P3500SCLRP is the appropriate selection.

Q: How do the on-state voltage differences affect circuit design?

A: The on-state voltage difference (5V for CR3500SC versus 4V for P3500SCLRP) is minimal and does not require circuit redesign. Both values fall within typical TVS thyristor operating ranges for this voltage class.

Q: Is the capacitance difference between parts significant?

A: The capacitance increase from 60pF to 65pF is negligible for most applications. This minor difference does not affect circuit performance in standard overvoltage protection configurations.

Q: What is the availability status of these parts?

A: The CR3500SC is obsolete with limited inventory. The P3500SCLRP is active production with substantial stock availability, ensuring reliable supply for current and future applications.