Infineon Technologies T1851N70TOHXPSA1

Overview

T1851N70TOHXPSA1 from Infineon Technologies is a phase-control thyristor designed for high-power AC line commutation in medium-voltage industrial drives and static var compensators (SVC). It delivers 1830 A average on-state current at 85°C case temperature, 7000 V repetitive peak off-state voltage, and withstands 50 kA surge current with 300 A/µs critical di/dt capability.

For engineers reviewing the T1851N70TOHXPSA1 datasheet, T1851N70TOHXPSA1 pinout, T1851N70TOHXPSA1 application, or T1851N70TOHXPSA1 equivalent, key selection criteria include clamping force range (45–65 kN), two-sided thermal resistance (6.0 K/W), gate trigger current ≤350 mA, and verified 600 µs turn-off time under rated commutation conditions.

Technical Context

This thyristor operates as a line-commutated, gate-controlled power switch in phase-angle controlled rectifiers and cycloconverters. Its design supports bidirectional blocking at 50/60 Hz over –40°C to +125°C junction temperature, with full DC blocking stability and high non-rupture case current.

It features a pressure-contact silicon pellet construction requiring precise mechanical clamping. Critical electrical behavior includes 2000 V/µs critical dv/dt rating, 12 mAs recovered charge at maximum junction temperature, and analytical transient thermal impedance data provided for anode-, cathode-, and two-sided cooling configurations.

Key Specifications

Pinout & Package

Package: Disc-type, double-side cooled, pressure-contact thyristor with 121 mm max diameter, 86 mm contact diameter, and 26 mm height. Requires precision torque-controlled mounting per Infineon's clamping specification.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TT1851N70KOF and STT1851N70TOF, T1851N70TOHXPSA1 uniquely combines 7000 V blocking, 1830 A rating, and validated 600 µs t_q under two-sided cooling-making it the sole option for 7.2 kV cycloconverters and 15+ MW SVC systems requiring simultaneous voltage, current, and commutation margin.

Availability

T1851N70TOHXPSA1 is available at Aetrix Electronics and suitable for static var compensation (SVC), medium voltage drives, load commutating inverters (LCI), and cycloconverter applications requiring stable component supply and long-term industrial lifecycle support.

Supply support for T1851N70TOHXPSA1 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, with global manufacturing and quality certification to ISO/TS 16949 and IECQ QC 080000.

This part belongs to Infineon's "Netz-Thyristor" product line, engineered specifically for high-reliability, high-power phase-control applications in utility-scale reactive power systems and heavy industrial motor drives.

FAQ

What is the required clamping force range for reliable operation?

The T1851N70TOHXPSA1 requires a mechanical clamping force between 45 kN and 65 kN to ensure uniform pressure across the silicon pellet interface. This range maintains consistent on-state voltage (v_T), prevents localized hot spots, and guarantees specified R_thJC of 6.0 K/W under two-sided cooling. Torque values must be verified using calibrated tools per Infineon's mounting guide.

Can this thyristor be used in single-sided heatsink configurations?

Yes, but with significant derating: R_thJC increases to 11.0 K/W (anode-cooled) or 13.0 K/W (cathode-cooled), reducing maximum allowable I_TAVM to approximately 1100 A at T_C = 85°C. Two-sided cooling is strongly recommended to achieve the rated 1830 A and maintain thermal stability in continuous-duty applications.

What gate drive parameters are necessary for reliable triggering?

A minimum gate trigger current of 350 mA (at 12 V anode-cathode voltage) with rise time ≤1 µs is required. The gate pulse width must exceed 20 µs to ensure latching, and peak gate power must not exceed 60 W for 0.5 ms pulses. Gate-cathode wiring inductance must be kept below 50 nH to avoid false turn-on from dv/dt coupling.

How does the 600 µs turn-off time impact system-level commutation design?

The 600 µs typical turn-off time (t_q) defines the minimum commutation interval: for 50 Hz AC supply, this allows reliable operation up to 167 Hz output frequency in cycloconverters. Designers must ensure sufficient reverse voltage duration (>2×t_q) and rate-of-fall (-di/dt) <10 A/µs during commutation to prevent failure due to recovery overshoot or tail current interruption.