TIP31C bipolar transistor — Specifications & Equivalents

About the TIP31C

The TIP31C is an NPN bipolar transistor with a collector–emitter voltage (V_CEO) rating of 100 V, a continuous collector current (I_C) of 3 A and a DC current gain (h_FE) of minimum 20. It can dissipate up to 40 W and is rated to a junction temperature of 150 °C. It is supplied in the TO220 package.

At a glance

• Type: NPN bipolar transistor
• Max collector–emitter voltage (V_CEO): 100 V
• Max collector current (I_C): 3 A
• DC current gain (h_FE): minimum 20
• Transition frequency (f_T): 3 MHz
• Power dissipation (P_D): 40 W
• Max junction temperature (T_J): 150 °C
• Package: TO220
• Manufacturer: Multi-source (originally a Texas Instruments TIP series)

Typical applications

Judging from its ratings the TIP31C is generally applied in power output and driver stages.

A transition frequency (f_T) of 3 MHz indicates the frequency range over which useful current gain remains available.

The quoted current gain of minimum 20 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 100 V, V_CBO 140 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 40 W, and that figure assumes the datasheet's mounting and ambient conditions — derate it for your own thermal design.

Choosing a replacement for the TIP31C

A drop-in substitute for the TIP31C must be the same NPN type and offer a collector–emitter rating of at least 100 V, a collector current rating of at least 3 A, current gain in the same ballpark as minimum 20 and a transition frequency of at least 3 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.

This is a widely second-sourced series, so verify parameters against the datasheet of the brand you are buying rather than assuming every version is identical.

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 TIP31C?

The TIP31C is an NPN bipolar junction transistor (BJT). It is rated for 100 V collector-emitter and 3 A continuous collector current.

What is the maximum voltage of the TIP31C?

Maximum collector-emitter voltage (Vceo) is 100 V, and collector-base (Vcbo) is 140 V.

How much current can the TIP31C handle?

Continuous collector current is rated at 3 A, with dissipation limited to 40 W.

What is the hFE of the TIP31C?

DC current gain (hFE) is quoted as minimum 20. Size base drive from the minimum value so the transistor saturates fully across production spread.

What package does the TIP31C 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 TIP31C?

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.