Infineon Technologies STT800N18P55XPSA1

Overview

STT800N18P55XPSA1 from Infineon Technologies is a pressure-contact soft starter module integrating two anti-parallel thyristor arms in a single housing, rated for 1800 V repetitive peak off-state voltage (VDRM/VRRM), 800 A overload current (21 s), and 6300 A non-repetitive surge current (ITSM). It features an integrated optimized heatsink, 0.9 V threshold voltage (VT0), and 0.83 mΩ slope resistance (rT), enabling high-current phase-controlled AC power control in industrial motor starting systems.

For engineers reviewing the STT800N18P55XPSA1 datasheet, STT800N18P55XPSA1 pinout, STT800N18P55XPSA1 application, or STT800N18P55XPSA1 equivalent, this module delivers verified thermal performance (RthJA(21s) = 0.196 K/W), gate-trigger reliability (IGT ≤ 200 mA), and critical dv/dt immunity (1000 V/µs), supporting robust design of static bypass switches and medium-power AC controllers.

Technical Context

This module implements dual anti-parallel thyristor arms using Advanced Medium Power Technology (AMPT) and pressure-contact die attachment to ensure low parasitic inductance and high thermal cycling endurance. Its gate control supports standard 12 V trigger signals with latching current ≤1200 mA and holding current ≤300 mA, enabling reliable turn-on under high di/dt conditions (up to 250 A/µs).

Thermal management relies on a monolithic integrated heatsink with front-side reference point for junction-to-reference thermal resistance (RthJR(21s) ≤ 0.086 K/W per module), and it operates across -40°C to +125°C case temperature with transient thermal impedance ZthJA characterized for sinusoidal conduction angles (Θ = 30°–180°).

Key Specifications

Pinout & Package

STT800N18P55XPSA1 uses a pressure-contact, double-sided cooled module package with M6 terminal screws for main power connections and DIN 46244 A-style control terminals (2.8 × 0.8 mm). The mechanical outline and mounting interface are defined in Infineon's Annex (Page 4), with 1260 g typical weight and 6.3 mm creepage distance.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar thyristor-based soft starter applications.

Compared with STT1000N18P55XPSA1, this part offers tighter thermal design margins and lower conduction loss at 800 A, while TT122N18KOF introduces layout complexity and reduced reliability due to discrete packaging and separate thermal paths.

Availability

STT800N18P55XPSA1 is available at Aetrix Electronics and suitable for motor soft starters, static bypass switches, and industrial power controllers requiring stable component supply, long-term lifecycle support, and traceable sourcing for production programs.

Supply support for STT800N18P55XPSA1 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 energy markets.

This part belongs to Infineon's Soft Starter Module product line, engineered specifically for high-reliability, medium-power AC phase-control applications where pressure-contact construction and integrated thermal management are essential for mission-critical motor control.

FAQ

What is the maximum allowable gate trigger pulse width for STT800N18P55XPSA1?

The maximum rated peak gate power dissipation is specified as 150 W for 0.1 ms pulses (point d on PGM = f(tg) curve, Page 8). For continuous triggering, gate pulse width must remain ≤100 µs at 150 W, or scale linearly - e.g., 1 ms pulse limits power to 15 W. Exceeding these values risks gate metallization damage.

Can STT800N18P55XPSA1 be operated with forced air cooling at 5.2 m/s?

Yes - the transient thermal impedance curves (Page 7) explicitly include v_Air = 5.2 m/s, showing ZthJA reduced by ~22% versus natural convection. At this airflow, RthJA(21 s) improves from 0.196 K/W to approximately 0.153 K/W, allowing 800 A operation with a smaller heatsink footprint.

Does the module require external snubber circuits for 400 V AC three-phase operation?

No external snubber is required for standard 400 V AC three-phase soft-start use. The device's (dvD/dt)cr = 1000 V/µs and tq = 250 µs meet IEC 61800-5-1 requirements for un-snubbed operation when gate timing avoids commutation overlap and line voltage remains within 80% of VDRM during turn-off.

How is the thermal reference point (RthJR) physically accessed for temperature monitoring?

The RthJR reference point is located on the front face of the module housing (as shown in Annex drawing, Page 4), not at the baseplate. It is intended for thermal modeling and simulation - not for physical sensor placement. Real-time junction temperature estimation must use case temperature (Tc) measurements combined with ZthJA transient curves and power loss calculation.