BC327 — PNP General Purpose Bipolar Junction Transistor

Overview

The BC327 (BC327-40) is a high-current PNP general-purpose bipolar junction transistor (BJT) manufactured by ON Semiconductor, Nexperia, and STMicroelectronics. Packaged in a TO-92 plastic housing, it is the direct PNP complementary transistor to the BC337.

With a high continuous collector current rating of $-800\text{ mA}$ (peak $-1.0\text{ A}$ ) and a collector-emitter breakdown voltage of $-45\text{ Volts}$ , the BC327 is widely used for high-side power switching, relay and solenoid driving, audio power amplifier push-pull driver stages, and LED power control.

Quick reference


Transistor Type	PNP Bipolar Junction Transistor (BJT)
Package	TO-92 (Flat face front, leads pointing down)
Collector-Emitter Voltage ( $V_{CEO}$ )	$-45\text{ V}$ max
Collector-Base Voltage ( $V_{CBO}$ )	$-50\text{ V}$ max
Continuous Collector Current ( $I_C$ )	$-800\text{ mA}$ continuous ( $-1000\text{ mA}$ peak)
DC Current Gain ( $h_{FE}$ )	100 to 630 (BC327-16: 100–250, BC327-25: 160–400, BC327-40: 250–630)
Transition Frequency ( $f_T$ )	$100\text{ MHz}$ min ( $200\text{ MHz}$ typical)
Power Dissipation ( $P_D$ )	$625\text{ mW}$ ( $T_A = 25^\circ\text{C}$ )

Pinout (TO-92 Package)

Looking at the flat face of the TO-92 package with leads pointing down:

text

        ┌─────────────┐
        │    BC327    │  (Flat Package Face)
        └─┬───┬───┬───┘
          1   2   3
          C   B   E

Pin	Name	Description
1	`COLLECTOR` (`C`)	Collector terminal (Load output connection)
2	`BASE` (`B`)	Base terminal (Control input via base resistor)
3	`EMITTER` (`E`)	Emitter terminal (High-side power rail $+V_{CC}$ )

Warning

Pinout Warning: European C-B-E Pinout!

BC327 (TO-92): Pin 1 = Collector, Pin 2 = Base, Pin 3 = Emitter (C-B-E).
PN2907A (TO-92): Pin 1 = Emitter, Pin 2 = Base, Pin 3 = Collector (E-B-C).

Specifications

Parameter	Symbol	Min	Typ	Max	Unit	Conditions
Collector-Emitter Voltage	$V_{CEO}$	-45	—	—	V	$I_C = -10\text{mA}, I_B = 0$
Collector Cutoff Current	$I_{CBO}$	—	—	-100	nA	$V_{CB} = -20\text{V}, I_E = 0$
DC Current Gain (BC327-40)	$h_{FE}$	250	—	630	—	$V_{CE} = -1\text{V}, I_C = -100\text{mA}$
Collector Saturation Volts	$V_{CE(sat)}$	—	-350	-700	mV	$I_C = -500\text{mA}, I_B = -50\text{mA}$
Base-Emitter On Voltage	$V_{BE(on)}$	—	—	-1.2	V	$V_{CE} = -1\text{V}, I_C = -300\text{mA}$

Common mistakes

Exceeding $625\text{ mW}$ package dissipation: Under heavy collector current (e.g. $-800\text{ mA}$ ), keep base drive sufficiently strong ( $I_B \ge I_C / 10$ ) so the transistor stays fully saturated.
Direct MCU connection for high-side supply rails $> 5\text{V}$ : When switching a $12\text{V}$ rail using a BC327, driving the base directly from a 3.3V or 5V MCU pin will keep the transistor ON permanently. Use an NPN transistor to pull the BC327 base LOW.

Notes

BC327 vs BC337: BC327 is PNP ( $800\text{ mA}$ high-side switch); BC337 is NPN ( $800\text{ mA}$ low-side switch).