SH300 Gas Discharge Tube - Equivalent & Substitute Parts

Part Overview

The SH300 is a 2-pole surface mount gas discharge tube (GDT) manufactured by Littelfuse Inc., rated for 300V 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 are required due to inventory constraints, supply chain considerations, or design flexibility needs.

Substiute Parts

SH300

Littelfuse Inc.In Stock: 1532SH300 Datasheet

Current PartRFQ

2035-30-SM-RPLF

Bourns Inc.In Stock: 8582035-30-SM-RPLF Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the SH300 is determined by strict equivalence across the following parameters:

• Voltage Rating: Substitute must have 300V DC spark over voltage (nominal)
• Current Rating: Substitute must have 5000A (5kA) impulse discharge current capacity at 8/20µs waveform
• Pole Configuration: Substitute must be 2-pole to maintain circuit topology compatibility
• Mounting Technology: Substitute must be surface mount (SMD) for PCB assembly compatibility
• Fail Mode: Substitute must have non-shorting fail characteristic
• Regulatory Compliance: Substitute must maintain ROHS3 compliance status
• Moisture Sensitivity: Substitute must have MSL 1 rating or better

The 2035-30-SM-RPLF from Bourns Inc. meets all these criteria. Package geometry differences (2-SMD Cylinder Square End versus 2-SMD Square End Block) are acceptable provided footprint compatibility is verified during design integration.

Parameter Comparison

Engineering Selection Recommendations

Both the SH300 and 2035-30-SM-RPLF are active production components with ROHS3 compliance and MSL 1 ratings, making them suitable for equivalent application in transient overvoltage protection circuits. Selection between these parts should be based on:

• Footprint Verification: Package geometry differences require confirmation that the 2-SMD Cylinder Square End case of the Bourns part is compatible with existing PCB layouts designed for the Littelfuse Square End Block package
• Supply Availability: Current inventory shows 1448 units of SH300 and 791 units of 2035-30-SM-RPLF, allowing flexibility based on procurement timelines
• Voltage Tolerance: The Bourns substitute specifies ±15% tolerance, whereas the Littelfuse part does not specify tolerance. This difference is acceptable for overvoltage protection applications where the nominal 300V rating is the controlling parameter
• Regulatory Continuity: Both parts maintain equivalent ROHS3 and MSL compliance, ensuring no regulatory impact from substitution

Frequently Asked Questions (FAQ)

Q: Can the 2035-30-SM-RPLF replace the SH300 in existing designs?

A: Yes, provided that PCB footprint compatibility is verified. Both parts have identical electrical ratings (300V, 5kA, 2-pole, non-shorting fail mode) and equivalent regulatory compliance. Package geometry differences require layout confirmation before implementation.

Q: What is the significance of the ±15% tolerance specification on the Bourns part?

A: The Bourns 2035-30-SM-RPLF specifies ±15% tolerance on the 300V spark over voltage, meaning the actual spark over voltage will fall between 255V and 345V. This tolerance band is typical for gas discharge tubes and does not affect substitution eligibility for overvoltage protection applications where the nominal 300V rating is the design parameter.

Q: Are there any differences in failure mode between these parts?

A: No. Both the SH300 and 2035-30-SM-RPLF are specified as non-shorting fail mode devices, meaning they will open circuit upon failure rather than short circuit.

Q: Do both parts have the same moisture sensitivity requirements?

A: Yes. Both parts are rated MSL 1 (Unlimited), indicating no moisture sensitivity restrictions for storage, handling, or assembly processes.

Q: What should be verified before implementing the Bourns substitute in production?

A: Footprint compatibility must be confirmed by comparing the 2-SMD Cylinder Square End package of the Bourns part against the 2-SMD Square End Block package of the Littelfuse part. Electrical performance is equivalent and requires no additional validation.