A940 bipolar transistor — Specifications & Equivalents

About the A940

The A940 is a PNP bipolar transistor with a collector–emitter voltage (V_CEO) rating of 150 V, a continuous collector current (I_C) of 1.5 A and a DC current gain (h_FE) of minimum 40. It can dissipate up to 25 W and is rated to a junction temperature of 150 °C. It is supplied in the TO220 package.

At a glance

• Type: PNP bipolar transistor
• Max collector–emitter voltage (V_CEO): 150 V
• Max collector current (I_C): 1.5 A
• DC current gain (h_FE): minimum 40
• Transition frequency (f_T): 4 MHz
• Power dissipation (P_D): 25 W
• Max junction temperature (T_J): 150 °C
• Package: TO220

Typical applications

Judging from its ratings the A940 is generally applied in power output and driver stages.

A transition frequency (f_T) of 4 MHz indicates the frequency range over which useful current gain remains available.

The quoted current gain of minimum 40 determines the base drive needed: divide your target collector current by the minimum h_FE, not the typical figure, when sizing the base resistor.

Biasing and absolute maximum ratings

Absolute-maximum breakdown limits are V_CEO 150 V, V_CBO 150 V and V_EBO 5 V (magnitudes). The emitter–base rating is the easiest to overlook and is often only a few volts, so protect the junction against reverse drive.

Dissipation is capped at 25 W, and that figure assumes the datasheet's mounting and ambient conditions — derate it for your own thermal design.

Choosing a replacement for the A940

A drop-in substitute for the A940 must be the same PNP type and offer a collector–emitter rating of at least 150 V, a collector current rating of at least 1.5 A, current gain in the same ballpark as minimum 40 and a transition frequency of at least 4 MHz for the same bandwidth.

Mechanically, check the replacement against the TO220 footprint and confirm the pin order — parts sharing a package outline do not always share a pinout.

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 A940?

The A940 is a PNP bipolar junction transistor (BJT). It is rated for 150 V collector-emitter and 1.5 A continuous collector current.

What is the maximum voltage of the A940?

Maximum collector-emitter voltage (Vceo) is 150 V, and collector-base (Vcbo) is 150 V.

How much current can the A940 handle?

Continuous collector current is rated at 1.5 A, with dissipation limited to 25 W.

What is the hFE of the A940?

DC current gain (hFE) is quoted as minimum 40. Size base drive from the minimum value so the transistor saturates fully across production spread.

What package does the A940 come in?

It is listed in TO220. Verify the pinout of the specific variant, as one outline can carry different pin assignments.

What can I use to replace the A940?

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.