Infineon Technologies TT425N18KOFXPSA1

Overview

TT425N18KOFXPSA1 from Infineon Technologies is a phase-control thyristor module designed for high-power AC line switching and rectification in industrial power electronics. It features 1800 V repetitive peak off-state voltage (VDRM/VRRM), 471 A average on-state current at 85 °C case temperature (ITAVM), 14.5 kA non-repetitive surge current (ITSM), and electrically insulated baseplate construction. It is used in soft starters, UPS rectifiers, and static bypass switches where robust gate-controlled turn-on and thermal stability are critical.

For engineers reviewing the TT425N18KOFXPSA1 datasheet, TT425N18KOFXPSA1 pinout, TT425N18KOFXPSA1 application, or TT425N18KOFXPSA1 equivalent, key selection criteria include verified VDRM/VRRM rating, ITAVM derating across conduction angles, RthJC (0.065 K/W per module), gate trigger thresholds (IGT ≤ 250 mA, VGT ≤ 1.5 V), and pressure-contact reliability for long-term cycling in drive and crowbar circuits.

Technical Context

This dual-thyristor module operates in phase-controlled AC applications using gate-triggered conduction with precise timing control over half-cycle conduction angles (Θ = 30°–180°). Its pressure-contact die attachment ensures low parasitic inductance and stable thermal resistance (RthJC = 0.065 K/W) under DC and sinusoidal load conditions.

The device supports both two-pulse (B2) and six-pulse (B6) bridge configurations, with validated current ratings up to 1200 A (B2) and 1600 A (B6) depending on heatsink thermal resistance (RthCA). Critical dynamic parameters include (diT/dt)cr = 120 A/µs and (dvD/dt)cr = 1000 V/µs, enabling reliable commutation in high-dI/dt environments like motor drives and battery chargers.

Key Specifications

Pinout & Package

TT425N18KOFXPSA1 is housed in an industrial-standard press-pack module with electrically insulated AlN ceramic baseplate (19 mm creepage), M1 mechanical mounting (6 Nm), and M2 terminal connections (12 Nm). The module contains two anti-parallel thyristor arms sharing a common insulated baseplate.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TT425N18KOFXPSA1, the 1600 V variant trades blocking voltage for lower cost in medium-voltage systems, while the 500 A version adds headroom for thermal-limited designs-neither offers pin or footprint compatibility, requiring PCB and heatsink re-evaluation.

Availability

TT425N18KOFXPSA1 is available at Aetrix Electronics and suitable for soft starters, UPS rectifiers, crowbar protection circuits, and static bypass switches requiring stable component supply across industrial OEM production cycles.

Supply support for TT425N18KOFXPSA1 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 semiconductors, microcontrollers, and sensor solutions for industrial, automotive, and renewable energy markets.

This part belongs to Infineon's high-power thyristor module product line, engineered specifically for ruggedized phase-control applications in motor drives, power conditioning, and grid-tied equipment where reliability under thermal and electrical stress is non-negotiable.

FAQ

What is the maximum allowable junction temperature for TT425N18KOFXPSA1?

The maximum junction temperature (Tvj max) is 125 °C, as specified in the thermal characteristics section of the official Infineon technical information document (Revision 3.6, p.3). Operation beyond this temperature risks irreversible degradation of the silicon die and pressure-contact interface, even if case temperature remains within limits. Thermal design must ensure that transient ZthJC curves and steady-state RthJC + RthCH + RthCA do not exceed this threshold under worst-case conduction angles and ambient conditions.

Does TT425N18KOFXPSA1 require forced cooling?

Yes-forced air or liquid cooling is required to sustain ITAVM = 471 A at TC = 85 °C. With RthJC = 0.065 K/W and RthCH ≤ 0.02 K/W, a typical RthCA of ≤ 0.15 K/W (achievable with finned heatsink + 5 m/s airflow) is necessary to maintain Tvj ≤ 125 °C. At natural convection (RthCA > 0.6 K/W), the usable ITAVM drops below 150 A, as shown in Figure 7 (TC vs. ITAVM curves).

Can TT425N18KOFXPSA1 be used in reverse-conducting mode?

No-it is a standard phase-control thyristor module with two unidirectional arms configured anti-parallel for AC conduction, not a reverse-conducting (RC) or reverse-blocking (RB) IGBT hybrid. Each arm conducts only in one direction (anode-to-cathode), and reverse voltage blocking is provided by the opposing arm. True reverse conduction (e.g., freewheeling in inductive loads) requires external diodes or a dedicated RC-IGBT module.

What gate drive voltage and current are needed to reliably trigger TT425N18KOFXPSA1?

A minimum gate trigger voltage of 1.5 V (VGT max) and current of 250 mA (IGT max) at 25 °C is required for guaranteed turn-on. For robust operation across temperature (-40 °C to +125 °C), a 15 V/1 A pulse (≥20 µs width) is recommended, as confirmed by the gate characteristic curve (Fig. 6) and latching current specification (IL ≤ 1500 mA). Gate resistor selection must limit peak current to ≤150 W (per PGM curve) to avoid gate damage.