HT32BRP Equivalent & Substitute Parts

Part Overview

The HT32BRP is a DIAC thyristor manufactured by Littelfuse Inc., rated for 30–34V breakover voltage with 2A peak output current in a DO-35 axial package. This component is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement.

DIACs are bidirectional thyristors used primarily in AC switching applications, particularly in triac gate triggering circuits. The HT32BRP's specifications define its operational envelope and determine which alternative components can serve as direct substitutes.

Substiute Parts

HT32BRP

Littelfuse Inc.In Stock: 1170HT32BRP 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 DIAC thyristors is determined by three critical parameters: breakover voltage range, peak output current rating, and physical package compatibility.

The HT32BRP operates within a 30–34V breakover window. Substitute parts must either match this voltage range exactly or provide a voltage range that encompasses the original specification without exceeding safe operating margins for the application circuit.

All substitute candidates maintain the 2A peak output current rating and DO-35 axial package format, ensuring mechanical and thermal compatibility. RoHS3 compliance and operating temperature range (–40°C to +125°C) are consistent across all listed alternatives.

The following substitutes are grouped by breakover voltage alignment:

Direct Voltage Match (30–34V): DB3TG (STMicroelectronics) — identical breakover voltage specification.

Overlapping Voltage Range (28–36V): DB3 (Fairchild Semiconductor) — breakover range encompasses the HT32BRP specification.

Higher Voltage Class (35–45V): DB4 (STMicroelectronics) — suitable only for applications requiring higher breakover voltage; not interchangeable for 30–34V circuits.

Parameter Comparison

Engineering Selection Recommendations

Primary Substitute: DB3TG (STMicroelectronics)

DB3TG is the optimal substitute for HT32BRP applications. It provides identical breakover voltage (30–34V), matching breakover current (15µA), and equivalent peak output current (2A). The component is in active production status, ensuring long-term availability and supply chain stability. RoHS3 compliance and DO-35 package compatibility are confirmed. This part requires no circuit redesign or application re-evaluation.

Secondary Substitute: DB3 (Fairchild Semiconductor)

DB3 offers a wider breakover voltage range (28–36V) that encompasses the HT32BRP specification. However, DB3 is classified as obsolete, presenting the same procurement challenge as the original part. The higher breakover current specification (50µA vs. 15µA) may affect gate triggering behavior in sensitive applications. Use only when DB3TG is unavailable and circuit tolerance permits the higher breakover current.

Higher Voltage Alternative: DB4 (STMicroelectronics)

DB4 operates in the 35–45V breakover range and is not a direct substitute for 30–34V applications. This part is suitable only for circuits designed for higher breakover voltage thresholds. Substituting DB4 into a 30–34V circuit will result in delayed or failed triggering.

All listed substitutes maintain ROHS3 compliance, operating temperature range, and peak output current specifications required for thermal and electrical compatibility.

Frequently Asked Questions (FAQ)

Q: Can DB3 replace HT32BRP in any application?

A: DB3 has a wider breakover voltage range (28–36V) that overlaps with HT32BRP (30–34V), making it functionally compatible for most applications. However, the higher breakover current (50µA) may alter gate triggering timing in precision circuits. Additionally, DB3 is obsolete, offering no long-term supply advantage. DB3TG is the preferred choice.

Q: Why is DB4 listed if it cannot replace HT32BRP?

A: DB4 is included for reference because it shares the same package, current rating, and manufacturer ecosystem. It is not a substitute for 30–34V applications but serves as an alternative for circuits requiring 35–45V breakover voltage. Selecting DB4 for a 30–34V design will cause circuit malfunction.

Q: What is the difference between breakover voltage and breakover current?

A: Breakover voltage is the applied voltage threshold at which the DIAC transitions to conduction. Breakover current is the leakage current flowing through the DIAC before breakover occurs. Both parameters affect circuit triggering behavior and must be considered during substitution.

Q: Are all listed parts available in the same packaging options?

A: All listed parts are supplied in DO-35 axial package format. Packaging variants (bulk, cut tape) may differ by supplier and availability, but the physical component package remains consistent across all alternatives.

Q: Does the obsolete status of HT32BRP affect its performance?

A: No. Obsolete status indicates discontinued manufacturing, not performance degradation. Existing HT32BRP inventory remains fully functional. Obsolescence necessitates substitution planning for future designs and long-term production support.