2SK1202 MOSFET — Specifications & Equivalents

About the 2SK1202

The 2SK1202 is a MOSFET with a drain–source voltage (V_DS) rating of 900 V and a continuous drain current (I_D) of 5 A. It can dissipate up to 100 W and is rated to a junction temperature of 150 °C. It is supplied in the TO3PI package.

At a glance

• Type: MOSFET
• Max drain–source voltage (V_DS): 900 V
• Max continuous drain current (I_D): 5 A
• Power dissipation (P_D): 100 W
• Max junction temperature (T_J): 150 °C
• Package: TO3PI
• Manufacturer: Multi-source (JIS registered part number)

Typical applications

With its 900 V drain–source rating the 2SK1202 sits in the high-voltage (offline) class of switching MOSFETs, typically found in primary-side switching in offline SMPS (flyback, forward and quasi-resonant), active PFC boost stages, half-bridge and full-bridge inverters, induction heating and electronic ballasts and BLDC and AC motor drives. The rating leaves usable margin above the ~325 V DC bus obtained by rectifying 230 VAC mains, which is why this class dominates offline power supplies.

Gate drive and switching notes

Keep gate–source voltage within the ±20 V maximum; exceeding it punctures the gate oxide and destroys the device permanently.

Choosing a replacement for the 2SK1202

A drop-in substitute for the 2SK1202 should match its polarity and offer a drain–source rating of at least 900 V and a continuous drain current rating of at least 5 A.

Mechanically, check the replacement against the TO3PI footprint and confirm the pin order — parts sharing a package outline do not always share a pinout.

Because 2SK1202 is a JIS-registered part number rather than one vendor's proprietary series, it is produced by several manufacturers. Datasheet figures vary slightly between them, so check the datasheet of the brand you actually buy — this also makes like-for-like sourcing easier.

Where the application switches inductive loads or runs near the voltage limit, keep extra headroom rather than choosing a part that only just meets the original numbers.

Frequently asked questions

What is the 2SK1202?

The 2SK1202 is a MOSFET (metal-oxide-semiconductor field-effect transistor). It is rated for 900 V drain-source and 5 A continuous drain current.

What is the maximum voltage of the 2SK1202?

The 2SK1202 has a maximum drain-source voltage (Vds) of 900 V. Treat this as an absolute maximum and design with margin, especially when switching inductive loads.

How much current can the 2SK1202 handle?

It is rated for 5 A of continuous drain current, with power dissipation limited to 100 W. Real-world capability depends on your heatsinking and ambient temperature.

What package does the 2SK1202 come in?

It is listed in TO3PI. Verify the pinout of the specific variant, as one outline can carry different pin assignments.

What can I use to replace the 2SK1202?

This page lists 17 candidate equivalents matched on electrical ratings and package. Any replacement should meet or exceed the original voltage, current and dissipation figures and use a compatible drive level.