2N457A bipolar transistor — Specifications & Equivalents

About the 2N457A

The 2N457A is a PNP bipolar transistor with a collector–emitter voltage (V_CEO) rating of 30 V, a continuous collector current (I_C) of 7 A and a DC current gain (h_FE) of 30–90. It can dissipate up to 85 W and is rated to a junction temperature of -65 to +110°C. It is supplied in the TO-3 package.

At a glance

• Type: PNP bipolar transistor
• Max collector–emitter voltage (V_CEO): 30 V
• Max collector current (I_C): 7 A
• DC current gain (h_FE): 30–90
• Power dissipation (P_D): 85 W
• Max junction temperature (T_J): -65 to +110°C
• Package: TO-3
• Manufacturer: Multi-source (JEDEC registered part number)

Typical applications

Judging from its ratings the 2N457A is generally applied in power output and driver stages.

The quoted current gain of 30–90 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 30 V, V_CBO 60 V and V_EBO 20 V (magnitudes). As a PNP device these are negative with respect to the emitter, so the collector sits below the emitter in normal operation. 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 85 W, and that figure assumes the datasheet's mounting and ambient conditions — derate it for your own thermal design.

Choosing a replacement for the 2N457A

A drop-in substitute for the 2N457A must be the same PNP type and offer a collector–emitter rating of at least 30 V, a collector current rating of at least 7 A and current gain in the same ballpark as 30–90.

Mechanically, check the replacement against the TO-3 footprint and confirm the pin order — parts sharing a package outline do not always share a pinout.

Because 2N457A 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 2N457A?

The 2N457A is a PNP bipolar junction transistor (BJT). It is rated for 30 V collector-emitter and 7 A continuous collector current.

What is the maximum voltage of the 2N457A?

Maximum collector-emitter voltage (Vceo) is 30 V, and collector-base (Vcbo) is 60 V.

How much current can the 2N457A handle?

Continuous collector current is rated at 7 A, with dissipation limited to 85 W.

What is the hFE of the 2N457A?

DC current gain (hFE) is quoted as 30–90. Size base drive from the minimum value so the transistor saturates fully across production spread.

What package does the 2N457A come in?

It is listed in TO-3. Verify the pinout of the specific variant, as one outline can carry different pin assignments.

What can I use to replace the 2N457A?

No verified equivalents are listed yet. Choose a part of the same polarity that meets or exceeds every rating above and shares a compatible package and pinout.