SH400 Gas Discharge Tube - Equivalent & Substitute Parts

Part Overview

The SH400 is a 2-pole surface mount gas discharge tube (GDT) manufactured by Littelfuse Inc., designed for overvoltage protection applications. With a nominal DC spark-over voltage of 400V and an impulse discharge current rating of 5000A (5kA), this component is classified as Active product status. The SH400 is packaged in a 2-SMD square end block configuration and is ROHS3 compliant with unlimited moisture sensitivity level (MSL 1). Substitute parts are identified when equivalent electrical performance and mechanical compatibility can be maintained across the specified parameters.

Substiute Parts

SH400

Littelfuse Inc.In Stock: 1890SH400 Datasheet

Current PartRFQ

2035-40-SM-RPLF

Bourns Inc.In Stock: 13162035-40-SM-RPLF Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the SH400 is determined by strict equivalence across the following parameters:

• Voltage - DC Spark Over (Nom): 400V (exact match required)
• Impulse Discharge Current (8/20µs): 5000A (5kA) (exact match required)
• Number of Poles: 2 (exact match required)
• Mounting Type: Surface Mount (exact match required)
• Package / Case: 2-SMD configuration (mechanical compatibility required)
• Fail Short: No (exact match required)
• RoHS Status: ROHS3 Compliant (regulatory requirement)

The 2035-40-SM-RPLF manufactured by Bourns Inc. meets all critical electrical and mechanical parameters. Tolerance specification (±15% for the substitute) does not affect substitution eligibility when nominal spark-over voltage and discharge current ratings are identical.

Parameter Comparison

Engineering Selection Recommendations

Both the SH400 and 2035-40-SM-RPLF maintain Active product status and are ROHS3 compliant. The 2035-40-SM-RPLF includes a ±15% tolerance specification on spark-over voltage, which provides additional documentation of performance characteristics while maintaining the same nominal 400V rating. Both components are REACH Unaffected and classified under ECCN EAR99 with identical HTSUS codes (8536.30.8000). Selection between these parts should be based on availability, lead time, and established supply chain preferences, as electrical and mechanical performance are equivalent.

Frequently Asked Questions (FAQ)

Q: Can the 2035-40-SM-RPLF replace the SH400 in existing designs?

A: Yes. Both components share identical nominal spark-over voltage (400V), impulse discharge current (5kA), pole configuration (2-pole), and surface mount package type. The 2-SMD square end block packages are mechanically compatible.

Q: What does the ±15% tolerance on the 2035-40-SM-RPLF mean for substitution?

A: The ±15% tolerance specification documents the acceptable variation range around the nominal 400V spark-over voltage for the Bourns part. This does not affect substitution eligibility, as the nominal rating matches the SH400 exactly.

Q: Are there any compliance differences between these parts?

A: No. Both parts are ROHS3 compliant, REACH Unaffected, and carry the same ECCN and HTSUS classifications. Moisture sensitivity level (MSL 1 - Unlimited) is identical for both.

Q: Does the package description difference ("Square End Block" vs. "Cylinder Square End") affect compatibility?

A: Both descriptions refer to 2-SMD surface mount packages with square end block geometry. The mechanical footprint and PCB mounting interface are compatible.

Q: What is the fail-short characteristic and why does it matter?

A: Both the SH400 and 2035-40-SM-RPLF are specified as "Fail Short: No," meaning they do not short-circuit upon failure. This is a critical safety and circuit protection characteristic that must remain consistent in substitution.