BD136 — -45V -1.5A Medium-Power PNP Bipolar Junction Transistor (TO-126)

Overview

The BD136 is a classic medium-power complementary silicon PNP bipolar junction transistor manufactured by STMicroelectronics, onsemi, and NXP. Housed in a through-hole TO-126 (SOT-32) plastic package with a central mounting hole, it provides a rugged, heatsinkable alternative to small-signal PNP transistors.

Featuring a collector-emitter voltage ( $V_{CEO}$ ) rating of $-45\text{V}$ , a continuous collector current rating of $-1.5\text{A}$ ( $-3.0\text{A}$ pulsed peak), a transition frequency ( $f_T$ ) of $190\text{ MHz}$ , and up to $12.5\text{ Watts}$ of power dissipation when mounted to a heatsink, the BD136 is the official PNP complement to the BD135. It is widely used in complementary audio amplifier pre-driver and driver stages, high-side DC motor speed controllers, relay and solenoid switching, and linear power supply series-pass regulators.

Quick reference


Transistor Type	Medium-Power Complementary Silicon PNP BJT
Package	TO-126 / SOT-32 (3-pin through-hole with mounting hole)
Collector-Emitter Breakdown ( $V_{CEO}$ )	$-45\text{ V}$ max
Collector-Base Breakdown ( $V_{CBO}$ )	$-45\text{ V}$ max
Continuous Collector Current ( $I_C$ )	$-1.5\text{ A}$ max ( $-3.0\text{ A}$ peak pulse)
Base Current ( $I_B$ )	$-0.5\text{ A}$ max
DC Current Gain ( $h_{FE}$ )	$40$ to $250$ (BD136-10: 63–160, BD136-16: 100–250)
Transition Frequency ( $f_T$ )	$190\text{ MHz}$ typ ( $> 50\text{ MHz}$ min)
Power Dissipation ( $P_D$ )	$12.5\text{ Watts}$ ( $T_C = 25^\circ\text{C}$ with heatsink) / $1.25\text{ W}$ in free air
Complementary NPN Pair	BD135 (45V NPN)

Pinout (TO-126 / SOT-32 Package - E-C-B Standard)

Looking at the printed front face of the TO-126 package with leads pointing downward:

text

        ┌───────────────┐
        │   O [Mount]   │
        ├───────────────┤
        │     BD136     │
        └─┬─────┬─────┬─┘
          1     2     3
          E     C     B

Pin	Name	Type	Description
1	`EMITTER (E)`	Emitter Terminal	Emitter (Connect to positive supply rail or emitter resistor)
2	`COLLECTOR (C)`	Collector Terminal	Collector (Connected to switched load; internally bonded to rear metal tab)
3	`BASE (B)`	Base Terminal	Base control input (Driven with base current via series resistor or input stage)

Specifications

Parameter	Symbol	Min	Typ	Max	Unit	Conditions
Collector-Emitter Breakdown	$V_{(BR)CEO}$	-45	—	—	V	$I_C = -10\text{mA}, I_B = 0$
Collector-Base Breakdown	$V_{(BR)CBO}$	-45	—	—	V	$I_C = -100\ \mu\text{A}, I_E = 0$
Emitter-Base Breakdown	$V_{(BR)EBO}$	-5.0	—	—	V	$I_E = -10\ \mu\text{A}, I_C = 0$
Collector Cutoff Current	$I_{CBO}$	—	—	-100	nA	$V_{CB} = -30\text{V}, I_E = 0$
DC Current Gain ( $h_{FE}$ )	$h_{FE}$	40	—	250	—	$I_C = -150\text{mA}, V_{CE} = -2.0\text{V}$
DC Current Gain ( $h_{FE}$ )	$h_{FE}$	25	—	—	—	$I_C = -500\text{mA}, V_{CE} = -2.0\text{V}$
Collector Saturation Voltage	$V_{CE(sat)}$	—	—	-0.50	V	$I_C = -500\text{mA}, I_B = -50\text{mA}$
Base Saturation Voltage	$V_{BE(sat)}$	—	—	-1.00	V	$I_C = -500\text{mA}, I_B = -50\text{mA}$

Comparison: BD136 vs BD138 vs BD140

Parameter	BD136	BD138	BD140
$V_{CEO}$ Voltage	$-45\text{ V}$	$-60\text{ V}$	$-80\text{ V}$
Max Current ( $I_C$ )	$-1.5\text{ A}$	$-1.5\text{ A}$	$-1.5\text{ A}$
Transition Freq ( $f_T$ )	$190\text{ MHz}$	$190\text{ MHz}$	$190\text{ MHz}$
Complementary NPN	BD135	BD137	BD139

Common mistakes

Assuming TO-92 (E-B-C) pinout: The TO-126 BD136 uses the European standard Emitter - Collector - Base (E-C-B) sequence from left to right. Swapping the base and collector leads is the most common assembly error.
Mounting to a heatsink without electrical insulation: The metal rear backing tab is internally bonded to Pin 2 (Collector). When mounting to a grounded chassis or shared heatsink, use a silicone thermal pad and insulating bushing.

Notes

Gain Grouping: Sub-grades are marked on the package: -6 ( $h_{FE} = 40 \dots 100$ ), -10 ( $h_{FE} = 63 \dots 160$ ), and -16 ( $h_{FE} = 100 \dots 250$ ).

Interface	Current-Driven Base Junction
Package	SOT-32 / TO-126 (3-pin through-hole with mounting hole)