SMP50-320 Equivalent & Substitute Parts

Part Overview

The SMP50-320 is a thyristor-based transient voltage suppressor (TVS) manufactured by STMicroelectronics, designed for surface mount applications in the DO-214AC (SMA) package. This component provides 320V off-state voltage protection with 150A peak pulse current capability at 8/20µs pulse duration. The SMP50-320 is classified as obsolete, necessitating identification of active equivalent and substitute components to maintain design continuity and ensure supply chain availability for new production and field replacements.

Substiute Parts

SMP50-320

STMicroelectronicsIn Stock: 770SMP50-320 Datasheet

Current PartRFQ

P3500S1ALRP

Littelfuse Inc.In Stock: 837P3500S1ALRP Datasheet

DirectRFQ

SMAJ300CA

MeritekIn Stock: 5114SMAJ300CA Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the SMP50-320 is determined by strict alignment of electrical and mechanical parameters within the transient voltage suppressor category. The primary substitution criteria are:

Direct Electrical Equivalence Requirements:

• Voltage - Off State: 320V
• Voltage - Breakover: 400V
• Current - Peak Pulse (8/20µs): 150A
• Current - Peak Pulse (10/1000µs): 50A
• Current - Hold (Ih): 150mA
• Number of Elements: 1

Mechanical Compatibility Requirements:

• Package / Case: DO-214AC (SMA)
• Mounting Type: Surface Mount

Compliance Requirements:

• RoHS3 Compliant
• Moisture Sensitivity Level (MSL): 1 (Unlimited)

The P3500S1ALRP (Littelfuse Inc.) qualifies as a direct equivalent substitute, meeting all electrical and mechanical parameters while maintaining active product status. The SMAJ300CA (Meritek) is classified as a similar substitute due to differences in device type (Zener TVS diode versus thyristor), voltage ratings, and current handling specifications, and is suitable only for applications where these parameter variations are acceptable.

Parameter Comparison

Engineering Selection Recommendations

P3500S1ALRP (Littelfuse Inc.) - Direct Equivalent:

The P3500S1ALRP is the primary substitute for the obsolete SMP50-320. This component maintains identical electrical specifications across all critical parameters: 320V off-state voltage, 400V breakover voltage, 150A peak pulse current (8/20µs), 50A peak pulse current (10/1000µs), and 150mA hold current. The P3500S1ALRP is manufactured by Littelfuse Inc. under the SIDACtor® series designation and carries active product status, ensuring long-term availability and supply chain continuity. Both components are ROHS3 compliant, REACH unaffected, and feature identical MSL ratings. The P3500S1ALRP is suitable for direct replacement in applications previously designed for the SMP50-320 without circuit modification.

SMAJ300CA (Meritek) - Similar Substitute:

The SMAJ300CA is classified as a similar substitute due to fundamental differences in device architecture and electrical characteristics. This component is a Zener-type TVS diode rather than a thyristor, resulting in different operational behavior. The SMAJ300CA features a 300V reverse standoff voltage (20V lower than the SMP50-320), 335V breakdown voltage (65V lower than the SMP50-320), and significantly reduced peak pulse current capability of 820mA at 10/1000µs pulse duration (compared to 50A for the SMP50-320). The SMAJ300CA is suitable only for applications where lower voltage ratings and reduced current handling are acceptable, or where Zener diode characteristics are specifically required. This component is not recommended as a direct replacement for the SMP50-320 in high-current transient suppression applications.

Frequently Asked Questions (FAQ)

Q: Can the P3500S1ALRP be used as a direct replacement for the SMP50-320?

A: Yes. The P3500S1ALRP meets all electrical and mechanical specifications of the SMP50-320, including voltage ratings, current handling, package type, and compliance certifications. No circuit modifications are required for direct substitution.

Q: What is the primary difference between the SMP50-320 and P3500S1ALRP?

A: Both components are thyristor-based TVS devices with identical electrical performance. The primary difference is manufacturer and product status: the SMP50-320 (STMicroelectronics) is obsolete, while the P3500S1ALRP (Littelfuse Inc.) is active. The P3500S1ALRP features slightly higher capacitance (50pF versus 25pF), which may affect high-frequency circuit behavior in sensitive applications.

Q: Why is the SMAJ300CA listed as a similar substitute rather than a direct equivalent?

A: The SMAJ300CA is a Zener diode TVS, not a thyristor. It has lower voltage ratings (300V standoff versus 320V), lower breakover voltage (335V versus 400V), and significantly reduced current handling (820mA versus 150A peak pulse). These differences make it unsuitable for direct replacement in applications requiring the full electrical specifications of the SMP50-320.

Q: Are all three components available in the same package?

A: Yes. The SMP50-320, P3500S1ALRP, and SMAJ300CA are all available in the DO-214AC (SMA) surface mount package, ensuring mechanical compatibility with existing PCB designs.

Q: What compliance certifications apply to these components?

A: All three components are ROHS3 compliant, REACH unaffected, and feature MSL rating of 1 (Unlimited), indicating no moisture sensitivity restrictions during storage and handling.

Q: Can the SMAJ300CA be used in place of the SMP50-320 in a high-current transient suppression circuit?

A: No. The SMAJ300CA is rated for only 820mA peak pulse current at 10/1000µs, compared to 50A for the SMP50-320. Using the SMAJ300CA in a circuit designed for 50A transient suppression would result in inadequate protection and potential component failure.

Q: What is the difference between the 8/20µs and 10/1000µs pulse duration ratings?

A: These represent different transient event profiles. The 8/20µs pulse (150A for SMP50-320) simulates lightning and switching transients with rapid rise times. The 10/1000µs pulse (50A for SMP50-320) simulates longer-duration transient events. Both ratings are provided to characterize device performance across different transient scenarios.