SH145 Gas Discharge Tube - Equivalent & Substitute Parts

Part Overview

The SH145 is a 2-pole surface mount gas discharge tube (GDT) manufactured by Littelfuse Inc., rated for 145V DC spark-over voltage with 5000A (5kA) impulse discharge current capacity. This component is designed for transient overvoltage protection in telecommunications, data line, and power supply applications. The part is currently in active production status with ROHS3 compliance and unlimited moisture sensitivity rating (MSL 1). Substitute parts are identified when equivalent electrical performance and mechanical compatibility can be maintained within the specified parameter tolerances for this product category.

Substiute Parts

SH145

Littelfuse Inc.In Stock: 943SH145 Datasheet

Current PartRFQ

2035-15-SM-RPLF

Bourns Inc.In Stock: 62702035-15-SM-RPLF Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the SH145 is determined by the following critical parameters:

Electrical Compatibility Requirements:

• Impulse Discharge Current (8/20µs): Must equal 5000A (5kA)
• Number of Poles: Must equal 2
• Fail Short characteristic: Must equal No
• Voltage - DC Spark Over tolerance: Acceptable variance within application circuit design margins

Mechanical Compatibility Requirements:

• Mounting Type: Must be Surface Mount
• Package / Case: Must be 2-SMD configuration with compatible footprint
• Packaging format: Tape & Reel (TR) standard

Regulatory & Compliance Requirements:

• RoHS Status: ROHS3 Compliant minimum
• Moisture Sensitivity Level: MSL 1 or equivalent
• REACH Status: REACH Unaffected or compliant

The substitute part 2035-15-SM-RPLF from Bourns Inc. meets all mandatory electrical and mechanical criteria, with a nominal spark-over voltage of 150V (5V differential from the SH145) and identical 5kA impulse discharge current rating.

Parameter Comparison

Engineering Selection Recommendations

Primary Part (SH145): Recommended for new designs and applications where Littelfuse supply chain and specifications are established. Active production status and full ROHS3 compliance support long-term availability.

Substitute Part (2035-15-SM-RPLF): Qualified as a direct substitute when SH145 availability is constrained or when Bourns supply chain is preferred. The 150V nominal spark-over voltage (5V higher than SH145) remains within acceptable protection thresholds for most overvoltage suppression applications. Identical 5kA impulse discharge current and 2-pole surface mount configuration ensure functional equivalence. Both parts maintain ROHS3 compliance and unlimited moisture sensitivity rating, supporting identical storage and assembly processes.

Frequently Asked Questions (FAQ)

Q: Can the 2035-15-SM-RPLF (150V) be used in place of the SH145 (145V)?

A: Yes. The 5V voltage differential represents a 3.4% increase in spark-over threshold. Both parts are rated for identical 5kA impulse discharge current and share the same 2-pole surface mount configuration. Substitution is valid for applications where the circuit design accommodates the higher protection threshold.

Q: Are the physical packages identical between SH145 and 2035-15-SM-RPLF?

A: Both parts use 2-SMD surface mount packages with square end block geometry, ensuring PCB footprint compatibility. The SH145 specifies "Square End Block" while the 2035-15-SM-RPLF specifies "Cylinder Square End"; both configurations are compatible with standard 2-SMD land patterns.

Q: Do both parts meet the same regulatory requirements?

A: Yes. Both SH145 and 2035-15-SM-RPLF are ROHS3 compliant, REACH unaffected, and rated MSL 1 (unlimited moisture sensitivity). They meet identical environmental and regulatory standards for commercial and industrial applications.

Q: What is the significance of the ±15% tolerance specification on the 2035-15-SM-RPLF?

A: The ±15% tolerance on the Bourns part (150V ±15%) defines the acceptable manufacturing variance range (127.5V to 172.5V). This specification does not affect substitution compatibility; it indicates the precision of the spark-over voltage at the component level.

Q: Can these parts be used interchangeably in existing assemblies?

A: Yes, provided the PCB layout and land pattern are compatible with the 2-SMD surface mount package. Both parts are fail-short devices with identical pole configuration and impulse current rating, supporting direct substitution in assembly processes.