HT34BRP Equivalent & Substitute Parts

Part Overview

The HT34BRP is a Diac/Sidac thyristor manufactured by Littelfuse Inc., rated for 32–36V breakover voltage with 2A peak output current in a DO-35 axial package. This component is classified as obsolete, making equivalent substitute parts necessary for new designs and ongoing production requirements. The HT34BRP operates across the industrial temperature range of –40°C to 125°C and complies with ROHS3 standards.

Substiute Parts

HT34BRP

Littelfuse Inc.In Stock: 920HT34BRP Datasheet

Current PartRFQ

DB3

Fairchild SemiconductorIn Stock: 770983DB3 Datasheet

MFR RecommendedRFQ

DB3TG

STMicroelectronicsIn Stock: 2484DB3TG Datasheet

MFR RecommendedRFQ

DB4

STMicroelectronicsIn Stock: 20892DB4 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the HT34BRP is determined by the following critical parameters:

• Package Compatibility: All substitute parts must use DO-204AH, DO-35, or axial packaging to ensure mechanical and electrical fit.
• Voltage - Breakover Range: The HT34BRP operates at 32–36V. Substitute parts must have breakover voltage ranges that overlap or fall within acceptable application tolerances.
• Current - Peak Output: All qualified substitutes must support 2A peak output current minimum.
• Operating Temperature Range: Substitutes must support –40°C to 125°C (TJ) or equivalent.
• Compliance: RoHS3 compliance is required for modern supply chains.

Based on these criteria, three substitute parts are qualified: DB3 (Fairchild Semiconductor), DB3TG (STMicroelectronics), and DB4 (STMicroelectronics).

Parameter Comparison

Engineering Selection Recommendations

DB3TG (STMicroelectronics) is the primary substitute for the HT34BRP. This part matches the breakover voltage range (30–34V overlaps the 32–36V specification), maintains identical breakover current (15 µA), and carries active product status with full ROHS3 compliance. The DB3TG is available in Cut Tape packaging with 2,420 units in stock.

DB3 (Fairchild Semiconductor) is a secondary option with a wider breakover voltage range (28–36V) that encompasses the HT34BRP specification. However, DB3 carries obsolete product status and exhibits higher breakover current (50 µA), which may affect circuit timing characteristics. This part is suitable only when DB3TG availability is constrained.

DB4 (STMicroelectronics) is qualified only for applications requiring higher breakover voltage (35–45V). The DB4 is not suitable as a direct substitute for the HT34BRP in circuits designed for 32–36V operation, as its minimum breakover voltage (35V) exceeds the HT34BRP maximum (36V) and introduces unacceptable circuit behavior drift.

Frequently Asked Questions (FAQ)

Q: Can DB4 replace HT34BRP in my circuit? A: No. The DB4 breakover voltage range (35–45V) does not align with the HT34BRP specification (32–36V). Using DB4 will shift circuit triggering thresholds outside design parameters.

Q: What is the difference between DB3 and DB3TG? A: Both parts meet the HT34BRP voltage specification. DB3TG is preferred because it maintains active product status and identical breakover current (15 µA). DB3 is obsolete and exhibits higher breakover current (50 µA), which may alter circuit timing.

Q: Are all substitutes pin-compatible with HT34BRP? A: Yes. All three substitute parts use identical DO-35 axial packaging, ensuring mechanical and electrical compatibility without PCB redesign.

Q: Do substitute parts meet compliance requirements? A: Yes. DB3, DB3TG, and DB4 are all ROHS3 compliant and carry EAR99 export classification matching the HT34BRP.

Q: Which substitute has the best long-term availability? A: DB3TG and DB4 carry active product status from STMicroelectronics, providing superior long-term supply assurance compared to obsolete alternatives.