Infineon Technologies T345N18EOFXPSA1

Overview

T345N18EOFXPSA1 from Infineon Technologies (formerly EUPEC) is a 1800 V, 345 A average on-state current, press-pack thyristor designed for high-power phase-controlled rectification and AC line commutation in industrial medium-voltage drives and HVDC converter valves. It features 0.75 mΩ slope resistance, 1.65 V max on-state voltage at 1000 A, and 1000 V/µs critical dv/dt rating. The device uses silicon pellet with pressure contact and is rated for 125 °C junction temperature.

For engineers reviewing the T345N18EOFXPSA1 datasheet, T345N18EOFXPSA1 pinout, T345N18EOFXPSA1 application, or T345N18EOFXPSA1 equivalent, key selection criteria include repetitive peak off-state voltage (VDRM/VRRM = 1800 V), RMS on-state current (ITRMSM = 550 A), surge current capability (ITSM = 8000 A @ 10 ms), thermal resistance (RthJC = 0.077 °C/W DC), and gate trigger sensitivity (IGT ≤ 200 mA).

Technical Context

This thyristor operates as a line-commutated, gate-controlled power switch in half- or full-wave controlled rectifier topologies. Its 1800 V blocking rating supports 1.1 kV AC line systems with safety margin, while its 345 A average current rating assumes two-sided cooling with heatsink KO.55-FB54-A and case temperature ≤85 °C. The 150 A/µs critical di/dt ensures reliable turn-on under high dv/dt stress.

Thermal design relies on transient impedance modeling (ZthJC analytical elements provided) and DC thermal resistance of 0.077 °C/W. Gate drive requires ≥1 A pulse with ≥1 A/µs diG/dt to achieve ≤4 µs delay time; holding current is 300 mA and latching current is 1.2 A at 25 °C.

Key Specifications

Pinout & Package

Press-pack construction with two main terminals (anode and cathode) and one gate terminal; no leads or solderable pins. Anode and cathode are flat copper contact surfaces (70 mm² Cu), clamped at 5.5 kN force. Gate terminal is a M4 screw terminal located on the side of the housing. Temperature measurement hole (ø3.2 × 1.5 mm deep) is provided adjacent to the anode side.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-power thyristor applications.

Compared with TT165N18SOF and T430N18TOF, T345N18EOFXPSA1 delivers optimal balance of current rating, thermal performance, and mechanical compatibility for retrofitting into existing 300–350 A industrial drive and SVC installations without redesigning heatsinks or clamping fixtures.

Availability

T345N18EOFXPSA1 is available at Aetrix Electronics and suitable for industrial medium-voltage drives, HVDC converter stations, static VAR compensators, and high-power electrolysis rectifiers requiring stable component supply and long-term obsolescence management.

Supply support for T345N18EOFXPSA1 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 AG is a German semiconductor manufacturer specializing in power semiconductors, microcontrollers, and sensor solutions for industrial, automotive, and energy infrastructure markets.

This part belongs to Infineon's high-power thyristor product line, engineered for reliability in grid-scale power conversion, where long service life, predictable aging behavior, and robustness under repetitive surge stress are primary design objectives.

FAQ

What is the maximum allowable case temperature for continuous operation?

The maximum allowable case temperature (tc op) is +125 °C, but the rated average on-state current ITAVM = 345 A is specified at tc = 85 °C with two-sided cooling. Operation above 85 °C requires derating per Fig. 3 in the datasheet; at 125 °C case temperature, ITAVM drops to approximately 190 A for θ = 180° conduction.

Does this thyristor require a heatsink, and if so, which one is recommended?

Yes, mandatory two-sided heatsinking is required. The datasheet specifies KO.55-FB54-A as the reference heatsink for all thermal curves. This heatsink provides symmetric thermal paths and is dimensioned for 5.5 kN clamping force; natural or forced air variants (VL = 50 l/s) are validated for different cooling modes per Figs. 4–5 and 8–9.

Can T345N18EOFXPSA1 be used in parallel configurations?

Yes, but only with strict dynamic matching and active current-sharing control. The device's 150 A/µs (di/dt)cr and low rT (0.75 mΩ) support parallel operation, yet static and dynamic imbalance must be mitigated via gate drive synchronization, identical layout, and temperature feedback-no inherent current-sharing capability is provided.

What gate drive specifications are required to ensure reliable turn-on?

A minimum gate trigger current of 1 A with diG/dt ≥ 1 A/µs is required to achieve tgd ≤ 4 µs at 25 °C. Gate voltage must reach ≥2 V within the pulse width (tg ≥ 20 µs). For reliable operation across temperature, gate power dissipation must stay below 150 W peak (Fig. 15), and non-trigger leakage (IGD ≤ 10 mA) must be respected in high-noise environments.