Infineon Technologies T731N44TOHXPSA1

Overview

T731N44TOHXPSA1 from Infineon Technologies is a high-power phase-control thyristor designed for medium-voltage AC line commutation in industrial drive rectifiers and soft starters. It delivers 870 A average on-state current at TC = 85°C, 4400 V repetitive peak off-state voltage (VDRM/VRRM), and withstands 18 kA surge current (ITSM) with 300 A/µs critical di/dt capability. Used in crowbar protection circuits and load-commutated inverters where robust gate-controlled turn-on and thermal stability across –40°C to +125°C are required.

For engineers reviewing the T731N44TOHXPSA1 datasheet, T731N44TOHXPSA1 pinout, T731N44TOHXPSA1 application, or T731N44TOHXPSA1 equivalent, key selection criteria include verified clamping force range (15–24 kN), two-sided cooling thermal resistance (17.0 K/kW), gate trigger current ≤350 mA, and transient recovery charge ≤5.5 mAs under rated commutation conditions.

Technical Context

This thyristor employs a pressure-contact silicon pellet structure enabling bidirectional heat dissipation and high case non-rupture current. Its gate-controlled turn-on is characterized by low threshold voltage (vT0 = 1.08 V) and steep slope resistance (rT = 0.65 mΩ), supporting stable conduction at up to 1200 A with <1.86 V on-state drop at junction temperature maximum.

The device features 2000 V/µs critical dv/dt rating and 500 µs circuit-commutated turn-off time (tq), optimized for line-frequency (50/60 Hz) phase-angle control in high-energy systems. Recovery behavior is defined by 5.5 mAs recovered charge (Qr) and 175 A peak reverse recovery current (IRM) under standardized -di/dt = 10 A/µs conditions.

Key Specifications

Pinout & Package

Package: Press-pack, double-sided cooled, disc-type thyristor with 76 mm outer diameter, 50 mm contact diameter, and 26 mm height. Requires controlled clamping force between 15–24 kN.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar phase-control thyristor applications.

Compared with TT731N44KOF and T731N44KO, the T731N44TOHXPSA1 provides superior noise immunity via dedicated auxiliary cathode, lower thermal resistance with true two-sided cooling, and validated 15–24 kN clamping window-making it optimal for mission-critical medium-voltage drives and crowbar systems.

Availability

T731N44TOHXPSA1 is available at Aetrix Electronics and suitable for soft starter systems, medium voltage drive rectifiers, crowbar protection circuits, and load-commutated inverters requiring stable component supply across extended production lifecycles.

Supply support for T731N44TOHXPSA1 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Infineon Technologies is a German semiconductor manufacturer specializing in power electronics, automotive ICs, and industrial control solutions.

This part belongs to Infineon's T731N series of high-power phase-control thyristors engineered for ruggedized medium-voltage energy conversion in industrial drives, traction, and grid infrastructure.

FAQ

What is the required gate trigger pulse specification for reliable turn-on?

The T731N44TOHXPSA1 requires a minimum gate trigger current of 3 A (latching current IL) with diG/dt ≥ 6 A/µs and pulse width ≥ 20 µs. Gate voltage must reach ≥2.5 V within the first 1 µs, and the gate-cathode loop inductance must be kept below 100 nH to avoid false turn-off during high di/dt transients.

How is thermal performance affected by clamping force deviation?

Clamping force below 15 kN increases contact resistance and raises RthJC beyond 17.0 K/kW, risking junction overheating above 125°C at rated current. Force above 24 kN risks silicon pellet fracture or housing deformation, degrading long-term reliability and increasing Qr drift after thermal cycling.

Can this thyristor replace older T731N44KOF units without redesign?

No-T731N44TOHXPSA1 uses a different mechanical interface (TOHXPSA1 housing) and requires updated mounting hardware, torque sequence, and thermal interface material. Its auxiliary cathode terminal also mandates separate gate return routing, unlike the single-cathode T731N44KOF.

What is the maximum allowable gate-cathode reverse voltage during off-state?

The gate-cathode junction is rated for –2.0 V reverse voltage. Exceeding this value-even briefly-can cause irreversible gate oxide damage. Gate drivers must include active clamping or Zener limiting to prevent negative swing beyond –1.5 V under all operating and fault conditions.