HT32RP DIAC Thyristor Equivalent & Substitute Parts

Part Overview

The HT32RP is a DIAC (Diode for Alternating Current) thyristor manufactured by Littelfuse Inc., rated for 27–37V 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 continuity. The HT32RP operates across the industrial temperature range of -40°C to 125°C and complies with ROHS3 standards.

Substiute Parts

HT32RP

Littelfuse Inc.In Stock: 925HT32RP 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 of the HT32RP is determined by the following electrical and mechanical parameters:

• Voltage - Breakover Range: The substitute must operate within or overlap the 27–37V range of the HT32RP
• Current - Peak Output: Must support minimum 2A peak output current
• Operating Temperature Range: Must maintain -40°C to 125°C operational capability
• Package / Case: Must use DO-204AH, DO-35, or equivalent axial package format
• RoHS Compliance: Must meet ROHS3 or equivalent environmental standards

Based on these criteria, three substitute parts are identified:

• DB3 (Fairchild Semiconductor): Breakover voltage 28–36V, overlaps the lower-to-mid range of HT32RP
• DB3TG (STMicroelectronics): Breakover voltage 30–34V, centered within HT32RP range, active product status
• DB4 (STMicroelectronics): Breakover voltage 35–45V, overlaps the upper range of HT32RP

Parameter Comparison

Engineering Selection Recommendations

DB3TG (STMicroelectronics) is the primary substitute for the HT32RP. This part maintains active product status, ensuring long-term availability and supply chain stability. The DB3TG operates within the central voltage range (30–34V) of the HT32RP specification, with matching breakover current (15 µA) and peak output current (2A). All electrical and mechanical parameters align with the original part, and ROHS3 compliance is confirmed.

DB3 (Fairchild Semiconductor) provides an alternative substitute with voltage coverage of 28–36V, overlapping the lower-to-mid range of the HT32RP. However, this part is classified as obsolete, which may limit future procurement availability.

DB4 (STMicroelectronics) is suitable only for applications requiring higher breakover voltage (35–45V). This part should be selected only when the circuit design specifically requires operation in the upper voltage range and is not a direct replacement for standard HT32RP applications.

Frequently Asked Questions (FAQ)

Q: Can DB3TG directly replace HT32RP in all applications?

A: DB3TG is electrically and mechanically compatible with HT32RP across the specified operating parameters. The voltage range 30–34V falls within the HT32RP specification of 27–37V, and all other electrical characteristics match. Verification of circuit-specific voltage requirements is necessary to confirm suitability.

Q: What is the difference between DB3 and DB3TG?

A: Both parts are DIAC thyristors in DO-35 packages with 2A peak output current. DB3 (Fairchild) has a breakover voltage of 28–36V and is obsolete. DB3TG (STMicroelectronics) has a breakover voltage of 30–34V and maintains active product status. DB3TG is preferred for new designs due to availability.

Q: When should DB4 be used instead of DB3TG?

A: DB4 is specified for applications requiring breakover voltage in the 35–45V range. The HT32RP upper limit is 37V, so DB4 is suitable only for circuits designed to operate at the upper end of the HT32RP specification or higher.

Q: Are all substitute parts RoHS compliant?

A: Yes. HT32RP, DB3, DB3TG, and DB4 are all ROHS3 compliant.

Q: What is the operating temperature range for these parts?

A: All parts (HT32RP, DB3, DB3TG, DB4) operate across -40°C to 125°C junction temperature, suitable for industrial applications.

Q: Does package format differ among these parts?

A: No. All parts use the DO-204AH, DO-35 axial package format, ensuring mechanical compatibility in existing PCB layouts.