HT36ARP DIAC Thyristor Equivalent & Substitute Parts

Part Overview

The HT36ARP is a DIAC (Diode for Alternating Current) thyristor manufactured by Littelfuse Inc., designed for AC switching and triggering applications. Packaged in DO-35 (DO-204AH) axial configuration, this component operates across a breakover voltage range of 32–40V with a peak output current of 2A and an operating temperature range of -40°C to 125°C.

The HT36ARP is classified as obsolete. Locating equivalent substitute parts is necessary to maintain design continuity, ensure supply chain availability, and support ongoing production or repair requirements for legacy systems utilizing this component.

Substiute Parts

HT36ARP

Littelfuse Inc.In Stock: 741HT36ARP 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 HT36ARP is determined by the following critical parameters:

• Package Compatibility: All substitute parts must use DO-35 (DO-204AH) axial packaging to ensure mechanical and electrical fit within existing PCB layouts and component footprints.
• Peak Output Current: All substitutes must maintain a peak output current of 2A to preserve circuit performance and current-handling capability.
• Operating Temperature Range: All substitutes must support the -40°C to 125°C operating temperature range to ensure reliability across the intended application environment.
• Breakover Voltage Range: Substitute parts must have breakover voltage specifications that overlap with or fall within acceptable tolerance margins of the original 32–40V specification. Slight variations in breakover voltage are permissible when the substitute's voltage range intersects with the original specification or provides equivalent triggering characteristics for the intended application.

The three substitute parts identified—DB3, DB3TG, and DB4—meet these core substitution criteria. Each maintains DO-35 packaging, 2A peak output current, and the required operating temperature range. Breakover voltage specifications vary to accommodate different circuit requirements within the DIAC thyristor family.

Parameter Comparison

Engineering Selection Recommendations

DB3TG (STMicroelectronics) is the primary recommended substitute. This part maintains an active product status, ensuring ongoing manufacturer support and supply chain availability. The DB3TG breakover voltage range of 30–34V overlaps substantially with the HT36ARP specification (32–40V), providing the closest electrical match. The current-breakover specification of 15 µA matches the original part exactly. ROHS3 compliance and REACH unaffected status confirm regulatory alignment.

DB4 (STMicroelectronics) serves as a secondary substitute for applications requiring higher breakover voltage tolerance. With a 35–45V range, the DB4 is suitable for circuits designed to operate at the upper end of the HT36ARP voltage specification. This part is also active and fully compliant with RoHS3 and REACH requirements.

DB3 (Fairchild Semiconductor) is a tertiary option. Although obsolete, it remains available in high inventory quantities (770,958 pcs). The 28–36V breakover range provides partial overlap with the original specification. The 50 µA breakover current differs from the HT36ARP, which may affect circuit triggering characteristics in sensitive applications.

All three substitutes maintain identical mechanical packaging (DO-35), peak output current (2A), and operating temperature range (-40°C to 125°C), ensuring functional compatibility within the specified electrical and thermal envelope.

Frequently Asked Questions (FAQ)

Q: Can the DB3 be used as a direct replacement for the HT36ARP?

A: The DB3 meets core substitution criteria: DO-35 packaging, 2A peak output current, and -40°C to 125°C operating temperature. However, the breakover voltage range (28–36V) is lower than the HT36ARP (32–40V), and the breakover current is 50 µA versus 15 µA. Application-specific circuit analysis is required to confirm suitability.

Q: What is the difference between DB3TG and DB4?

A: Both are STMicroelectronics DIAC thyristors in DO-35 packaging with 2A peak output current. The DB3TG has a 30–34V breakover range and 15 µA breakover current, matching the HT36ARP current specification more closely. The DB4 has a 35–45V breakover range and 50 µA breakover current, suitable for higher voltage applications. Select based on your circuit's required breakover voltage.

Q: Are all substitutes RoHS3 compliant?

A: Yes. The HT36ARP, DB3, DB3TG, and DB4 are all ROHS3 compliant, confirming lead-free and restricted substance compliance for modern manufacturing and environmental standards.

Q: Does packaging differ between these parts?

A: No. All parts use identical DO-35 (DO-204AH) axial packaging, ensuring mechanical compatibility with existing PCB layouts and component footprints.

Q: Which substitute has the best long-term availability?

A: DB3TG and DB4, both manufactured by STMicroelectronics, carry active product status, indicating ongoing production and manufacturer support. DB3 is obsolete but currently available in large inventory quantities.