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STMicroelectronics T4050-6PF — Discrete Semiconductors

STMicroelectronics T4050-6PF Snubberless Triac, 40 A, 600 V

MPNT4050-6PF
End of Life

STMicroelectronics Snubberless™ Alternistor triac, T4050-6PF, 40 A RMS on-state, 600 V off-state, 400 A non-repetitive surge, TO-3PF through-hole package, industrial temperature range.

$5.55Ref. price · indicative, final on quote
STMicroelectronics T4050-6PF datasheet (PDF)
PackagingTO-3P-3 Full Pack
SeriesSnubberless™
Independent supplier — new & surplus stockAuthenticity-screened · ESD-safe packingListing updated Aug 2026

Specifications

T4050-6PF specifications
ParameterValue
SeriesSnubberless™
Triac typeAlternistor - Snubberless
MountingThrough Hole
Voltage - off state600 V
Voltage - gate trigger (Vgt)1.3 V
Current - hold (Ih)85 mA
Current - gate trigger (Igt)50 mA
Current - on state (It (RMS))40 A
Current - non rep. surge 50, 60Hz420A, 400A
Operating temperature-40°C ~ 125°C (TJ)
PackageTube
ConfigurationSingle
CaseTO-3P-3 Full Pack

Product details

40 A RMS, 600 V — Snubberless™ Alternistor for inductive AC loads

The STMicroelectronics T4050-6PF is a Snubberless™ Alternistor triac rated for 40 A RMS on-state current and 600 V off-state voltage, housed in a TO-3PF through-hole package. It is designed for AC power switching where inductive loads (motors, transformers, solenoids) generate high dV/dt stress.

Surge handling and thermal limits

Non-repetitive surge current is rated at 420 A for 50 Hz and 400 A for 60 Hz half-cycle, giving headroom for motor start-up and capacitive inrush. The TO-3PF full-pack package isolates the tab, simplifying heatsink mounting without an insulating pad.

Gate drive and holding current

Maximum gate trigger current is 50 mA, with a maximum gate trigger voltage of 1.3 V, compatible with standard logic-level drivers or optocoupler outputs. The maximum holding current of 85 mA ensures the triac latches on cleanly with moderate load currents and does not drop out during load transients.

Frequently asked questions

What are the exact specifications of T4050-6PF?

The T4050-6PF is a Snubberless™ Alternistor triac rated for 40 A RMS on-state current, 600 V off-state voltage, 400 A non-repetitive surge at 60 Hz, and 420 A at 50 Hz. Gate trigger current is 50 mA max, gate trigger voltage is 1.3 V max, and holding current is 85 mA max. It comes in a TO-3PF through-hole package.

What is the replacement or equivalent for T4050-6PF?

Within the Snubberless™ family, the T3035H-8I is a lower-current (30 A) 800 V variant in a different package (TO-220I), and the T1235H-6I is a 12 A 600 V option. Neither is a direct pin-compatible replacement; the T4050-6PF is the 40 A 600 V TO-3PF variant in the series.

How does T4050-6PF compare to other 40A triacs like BTA40?

The T4050-6PF is a Snubberless™ Alternistor, meaning it does not require an external RC snubber for inductive loads, unlike standard triacs such as the BTA40 series. This reduces BOM count and board area in motor-drive and transformer applications.