2N6661-2 MOSFET — Specifications & Equivalents

About the 2N6661-2

The 2N6661-2 is a MOSFET with a drain–source voltage (V_DS) rating of 90 V and a continuous drain current (I_D) of 0.86 A. It can dissipate up to 0.725 W and is rated to a junction temperature of 150 °C. It is supplied in the TO-39 package.

At a glance

• Type: MOSFET
• Max drain–source voltage (V_DS): 90 V
• Max continuous drain current (I_D): 0.86 A
• Power dissipation (P_D): 0.725 W
• Max junction temperature (T_J): 150 °C
• Package: TO-39
• Manufacturer: Multi-source (JEDEC registered part number)

Typical applications

With its 90 V drain–source rating the 2N6661-2 sits in the mid-range class of switching MOSFETs, typically found in 24 V and 48 V industrial and battery systems, motor drives and H-bridges and load and hot-swap switching.

At 0.86 A it is aimed at small-signal and light-load switching rather than power conversion.

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.

Switching behaviour is characterised by an output capacitance (C_oss) of 15 pF, which together with the gate drive determines switching loss and the practical upper frequency limit.

Choosing a replacement for the 2N6661-2

A drop-in substitute for the 2N6661-2 should match its polarity and offer a drain–source rating of at least 90 V and a continuous drain current rating of at least 0.86 A.

Mechanically, check the replacement against the TO-39 footprint and confirm the pin order — parts sharing a package outline do not always share a pinout.

Because 2N6661-2 is a JEDEC-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 2N6661-2?

The 2N6661-2 is a MOSFET (metal-oxide-semiconductor field-effect transistor). It is rated for 90 V drain-source and 0.86 A continuous drain current.

What is the maximum voltage of the 2N6661-2?

The 2N6661-2 has a maximum drain-source voltage (Vds) of 90 V. Treat this as an absolute maximum and design with margin, especially when switching inductive loads.

How much current can the 2N6661-2 handle?

It is rated for 0.86 A of continuous drain current, with power dissipation limited to 0.725 W. Real-world capability depends on your heatsinking and ambient temperature.

What package does the 2N6661-2 come in?

It is listed in TO-39. Verify the pinout of the specific variant, as one outline can carry different pin assignments.

What can I use to replace the 2N6661-2?

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.