FJA4310 bipolar transistor — Specifications & Equivalents

About the FJA4310

The FJA4310 is an NPN bipolar transistor with a collector–emitter voltage (V_CEO) rating of 140 V, a continuous collector current (I_C) of 10 A and a DC current gain (h_FE) of minimum 50. It can dissipate up to 100 W. It is supplied in the TO3PN package.

At a glance

• Type: NPN bipolar transistor
• Max collector–emitter voltage (V_CEO): 140 V
• Max collector current (I_C): 10 A
• DC current gain (h_FE): minimum 50
• Power dissipation (P_D): 100 W
• Package: TO3PN

Typical applications

Judging from its ratings the FJA4310 is generally applied in power output and driver stages.

The quoted current gain of minimum 50 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 140 V, V_CBO 200 V and V_EBO 6 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 100 W, and that figure assumes the datasheet's mounting and ambient conditions — derate it for your own thermal design.

Choosing a replacement for the FJA4310

A drop-in substitute for the FJA4310 must be the same NPN type and offer a collector–emitter rating of at least 140 V, a collector current rating of at least 10 A and current gain in the same ballpark as minimum 50.

Mechanically, check the replacement against the TO3PN 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 FJA4310?

The FJA4310 is an NPN bipolar junction transistor (BJT). It is rated for 140 V collector-emitter and 10 A continuous collector current.

What is the maximum voltage of the FJA4310?

Maximum collector-emitter voltage (Vceo) is 140 V, and collector-base (Vcbo) is 200 V.

How much current can the FJA4310 handle?

Continuous collector current is rated at 10 A, with dissipation limited to 100 W.

What is the hFE of the FJA4310?

DC current gain (hFE) is quoted as minimum 50. Size base drive from the minimum value so the transistor saturates fully across production spread.

What package does the FJA4310 come in?

It is listed in TO3PN. Verify the pinout of the specific variant, as one outline can carry different pin assignments.

What can I use to replace the FJA4310?

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.