Fast Switching Thyristor 250 amp, TFI371-250 (1000 – 1400V), Stud Type

Average forward current, ITAV 250A
Voltage, VDRM/VRRM 1000–1400V
Voltage code, VRRM / 100 10 – 14
TFI371-250 on request
M24x1.5 mm
Weight 470 g
Datasheet Datasheet

Fast Switching Thyristor TFI371-250 AS ENERGITM in stud is a fast switching semiconductor device, designed for converting and control DC and AC currents up to 250A with frequency up to 10kHz in circuits with voltages up to 1000V – 1400V (voltage class from 10 to 14). Thyristor package type – ST7, mounting standard thread M24x1.5, (on request, UNF thread 3/4"-16UNF-2A), weight – 470 g.

Fast switching (pulse) thyristors are devices with reduced tq, trr, Qrr values and with a higher value (diT/dt)cr (up to 2500 A/µs) designed to operate at higher frequencies modes (up to 10kHz). The thyristor parameters of VTM, tq, Qrr are interconnected, so a decrease in the value of tq and Qrr leads to an increase in VTM. Fast switching thyristors are characterized with a very low turn-off time that sets them apart from the standard models. They are used in welding, induction heating and melting, electric transportation, AC drives, UPS, and other systems requiring short turn-on and turn-off times. The thyristors have an industry-standard ceramic sealed housing isolating the functional part and the semiconductor element from mechanical impacts and environment.

Fast switching thyristors are supplied in stud design. The base of the thyristor is the Anode, the flexible power lead is the Cathode, the flexible wire exiting the base of the power lead is the auxiliary cathode, the flexible wire exiting the case is the control electrode (Gate). This thyristor can be an alternative product, replacement, analog, equivalent for other types fast switching thyristors 210A, 220A, 230A, 240A, 250 amp in a stud housing.

Air and water heat sinks are used to cool the thyristors. To provide reliable thermal and electrical contact with the heatsink a tightening torque Md must be observed during assembly. For better heat dissipation of thyristor during assembly, heat conducting paste is used.

Specifications and parameters, datasheets PDF, sample technical passport, dimensions, outline drawings, case diagrams thyristors, recommended coolers are listed below.

Our company provides a quality guarantee for power fast switching thyristors of 2 years from the date of purchase. When supplying thyristors, if necessary, we provide technical passport, certificate of conformity.

Fast stud thyristor ratings: TFI371-250-10 (250A 1000V), TFI371-250-11 (250A 1100V), TFI371-250-12 (250A 1200V), TFI371-250-14 (250A 1400V).

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The final price for stud fast switching thyristors depends on the voltage class, quantity, delivery terms, manufacturer, country of origin and form of payment.

General specifications of stud fast switching thyristors TFI371-250:

Fast switching thyristor specifications TFI371-250
Maximum allowable average forward current (Case temperature) IT(AV) (Tcase) 250 A (88°C)
266 A (85°C)
399 A (55°C)
Repetitive peak off-state voltage; Repetitive peak reverse voltage VDRM/VRRM 1000-1400 V
RMS on-state current ITRMS 392 A
Surge on-state current ITSM 7.0 kA
Safety factor I2t 240 kA2·s
Peak on-state voltage, max VTM 1.8 V
Peak on-state current ITM 785 A
On-state threshold voltage, max VT(TO) 1.168 V
On-state slope resistance, max rT 0.915 mΩ
Turn-off time, max tq 25-50 µs
Repetitive peak off-state and Repetitive peak reverse currents, max IDRM/IRRM 70 mA
Critical rate of rise of off-state voltage, min (dVD/dt)cr 200-2500 V/µs
Gate trigger direct voltage, max VGT 2.5 V
Gate trigger direct current, max IGT 250 mA
Critical rate of rise of on-state current (diT/dt)cr 1600 A/µs
Temperature of p-n junction, max Tvj max 125 ºC
Thermal resistance, junction to case, max Rth(j-c) 0.85 ºC/W
Mounting torque Md 25-35 N·m
Weight, approx. W 470 g
Package type, Thread Outline ST7
Recommended heatsinks Heatsinks O181, O281, OM105
Datasheet PDF PDF

Part Numbering Guide for Fast Switching Thyristors TFI371-250:

TFI 371 250 14 9 5 2
TFI Fast Switching Thyristor (Fast Impulse Thyristor), brand AS ENERGITM
371 Thyristor type (stud type).
250 Average current in open state IT(AV), Amp.
14 Voltage class VRRM / 100  (Nominal voltage – 1400 V).
9 Parameter of the critical rate of rise of off-state voltage (dVD/dt)cr:
Alpha-numeric coding 0 P3 E3 A3 P2 K2 E2 A2 T1 P1 M1
Digital coding 0 1 2 3 4 5 6 7 8 9
Value, V/µs not standardized 20 50 100 200 320 500 1000 1600 2000 2500
5 Parameter of turn-off time tq:
Alpha-numeric coding 0 C3 E3 H3 K3 M3 P3 T3 X3 A4 B4 C4 E4
Digital coding 0 1 2 3 4 5 6 7 8 9
Value, µs not standardized 63 50 40 32 25 20 16 12.5 10 8 6.3 5
2 Parameter of turn-on time tgt:
Alpha-numeric coding 0 T3 A4 B4 C4 H4 K4 M4 P4 T4 X4 A5 C5
Digital coding 0 1 2 3 4 5 6 7 8
Value, µs not standardized 16 10 8 6.3 4 3.2 2.5 2.0 1.6 1.25 1.0 0.63

Polarity (anode, cathode, gate) and dimensions of stud fast switching thyristor TFI371-250:

Thyristor polarity Dimensions

Fast thyristor TFI371-250 datasheet:

PDFDownload pdf datasheet for thyristors TFI371-250

Technical Passport for Thyristors (sample):

When supplying thyristors, if necessary, we provide technical passport and certificate of conformity.

  • Technical Passport
  • Technical Passport
  • Technical Passport

High Power Semiconductors AS ENERGITM

Our company is engaged in the manufacturer and sale of wide range of power semiconductors (power thyristors, modules, rectifier diodes, rotor and welding diodes, triacs etc.) currents up to 15000A and voltages to 9000V, and air and water heatsinks to them. You can buy semiconductors in any volumes, and when ordering large lots, the price will be lower.
We have earned the trust of customers and supply products all over the world.

For questions regarding the acquisition of Power Thyristors, Diodes, Modules send an email request to:

[email protected]

And we will provide you a commercial offer for delivery.
For a large number, we will provide an individual price!!!

We are open to manufacture products at our production facilities
according to your requests and technical task.

Photo Gallery

The photo gallery shows many different semiconductor devices, semiconductor chips and SCRs produced by AS ENERGITM, examples of test reports.

Heat sinks for power stud fast switching thyristors:

Heat sinks (radiators) are used for cooling of power semiconductor devices in stud design.

Heat sinks of coolers are made of aluminum radiator profiles and do not require additional protective coating when used in various climatic conditions.

See for more information about heatsinks: "Air-cooled heatsinks for stud devices".

Photo of High Power Stud Type Fast Switching Thyristors:

  • Stud Fast Switching Thyristors
  • Stud Fast Switching Thyristors
  • Stud Fast Switching Thyristors
  • Stud Fast Switching Thyristors
  • Stud Fast Switching Thyristors
  • Stud Fast Switching Thyristors

icon Why choose AS ENERGITM

  • Own production facilities, including semiconductor silicon chips production
  • European brand - 100% quality, favorable price, short production terms
  • Over 20 years of experience in the semiconductor industry
  • Clients from more than 50 countries trust us
  • 20000 items in the product line for currents from 10A to 15000A, voltages from 100V to 9000V
  • We produce analogues of other manufacturers' products
  • Guaranteed certified quality, warranty period of operation - 2 years


Quality Warranty

Our products are certified and correspond to international standards.
Our company provides a quality guarantee for products of 2 years.
We provide certificates of conformity, reliability reports, data sheets and technical passports at the request of the customer.


Each product is tested for the main parameters, and Test reports of the parameters for each product are provided.

Test Report

Geography of partnership

AS ENERGITM company manufactures and supplies power semiconductors to more than 50 countries around the world.


Logistics and Delivery

We deliver our products all over the world with the services of logistics companies: DHL, TNT, UPS, EMS, Fedex, Aramex.
Products can be delivered by any means of transport: air, sea, rail and road.


AS ENERGITM Semiconductors Manufacturing

Our products range includes rectifier diodes, phase control thyristors in disc and stud design, avalanche diodes and thyristors, fast switching, high frequency thyristors, fast recovery, welding and rotor diodes, triacs, bridge rectifiers, power modules (thyristor, diode, thyristor-diode, IGBT), and air and water heatsinks to them.

Power diodes and thyristors are produced for currents from 10A to 15000A, voltage range from 100V to 9000V.
Power diode and thyristor modules are produced from 25A and up to 1250A, voltage range 400V - 4400V.
The range of power semiconductors also includes equivalent, replacement, analogue and alternative semiconductor devices of global manufacturers.

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