2N5401 — -150V -600mA High-Voltage PNP BJT (TO-92)

Overview

The 2N5401 (and its surface-mount version MMBT5401) is an industry-standard high-voltage small-signal PNP bipolar junction transistor manufactured by onsemi, Fairchild, Central Semiconductor, and STMicroelectronics. Housed in a through-hole TO-92 plastic package with standard Emitter - Base - Collector (E-B-C) pinout, it is engineered for high-voltage amplification and switching.

Featuring an exceptionally high collector-emitter breakdown voltage ( $V_{CEO}$ ) of $-150\text{V}$ ( $-160\text{V}$ $V_{CBO}$ ), a continuous collector current rating of $-600\text{ mA}$ , and a transition frequency ( $f_T$ ) of $100\text{ MHz} \dots 300\text{ MHz}$ , the 2N5401 is the standard PNP complementary pair to the 2N5551. It is widely employed in hi-fi audio power amplifier Voltage Amplification Stages (VAS) and differential input pairs, 48V telecom line interfaces (on-hook/off-hook switches), gas discharge display drivers, high-voltage active constant-current sources, and industrial level shifters.

Quick reference


Transistor Type	High-Voltage Small-Signal Silicon PNP BJT
Package	TO-92 (3-pin through-hole) / SOT-23 (MMBT5401)
Collector-Emitter Breakdown ( $V_{CEO}$ )	$-150\text{ V}$ max
Collector-Base Breakdown ( $V_{CBO}$ )	$-160\text{ V}$ max
Emitter-Base Breakdown ( $V_{EBO}$ )	$-5.0\text{ V}$ max
Continuous Collector Current ( $I_C$ )	$-600\text{ mA}$ max
DC Current Gain ( $h_{FE}$ )	$50$ to $240$ ( $I_C = -10\text{mA}, V_{CE} = -5.0\text{V}$ ) / $\ge 50$ at $-50\text{mA}$
Transition Frequency ( $f_T$ )	$100\text{ MHz}$ min ( $100\text{ MHz} \dots 300\text{ MHz}$ typ)
Total Power Dissipation ( $P_D$ )	$625\text{ mW}$ ( $T_A = 25^\circ\text{C}$ )
Operating Temperature Range	$-55^\circ\text{C}$ to $+150^\circ\text{C}$
Complementary NPN Pair	2N5551 (160V NPN BJT)

Pinout (TO-92 Package - E-B-C Standard)

Looking at the flat front face with leads pointing downward:

text

        ┌─────────┐
        │  TO-92  │
        │ 2N5401  │
        └─┬───┬───┬─┘
          1   2   3
          E   B   C

Pin	Name	Type	Description
1	`EMITTER (E)`	Emitter Terminal	Emitter (Connect to positive supply rail or emitter degeneration resistor)
2	`BASE (B)`	Base Terminal	Base control input (Driven with base current via input stage or bias network)
3	`COLLECTOR (C)`	Collector Terminal	Collector output (Connected to negative rail or load)

Specifications

Parameter	Symbol	Min	Typ	Max	Unit	Conditions
Collector-Emitter Breakdown	$V_{(BR)CEO}$	-150	—	—	V	$I_C = -1.0\text{mA}, I_B = 0$
Collector-Base Breakdown	$V_{(BR)CBO}$	-160	—	—	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	$I_{CBO}$	—	—	-50	nA	$V_{CB} = -120\text{V}, I_E = 0$
DC Current Gain ( $h_{FE}$ )	$h_{FE}$	50	—	—	—	$I_C = -1.0\text{mA}, V_{CE} = -5.0\text{V}$
DC Current Gain ( $h_{FE}$ )	$h_{FE}$	50	—	240	—	$I_C = -10\text{mA}, V_{CE} = -5.0\text{V}$
DC Current Gain ( $h_{FE}$ )	$h_{FE}$	50	—	—	—	$I_C = -50\text{mA}, V_{CE} = -5.0\text{V}$
Collector Saturation Voltage	$V_{CE(sat)}$	—	—	-0.20	V	$I_C = -10\text{mA}, I_B = -1.0\text{mA}$
Collector Saturation Voltage	$V_{CE(sat)}$	—	—	-0.50	V	$I_C = -50\text{mA}, I_B = -5.0\text{mA}$
Base Saturation Voltage	$V_{BE(sat)}$	—	—	-1.00	V	$I_C = -50\text{mA}, I_B = -5.0\text{mA}$

Typical Application: High-Voltage Audio Power Amplifier VAS Stage

In high-power audio amplifiers operating from $\pm 45\text{V}$ rails, the 2N5401 provides the high-voltage gain stage without risk of breakdown:

text

                            +45V Positive Supply Rail
                                        │
                                 [Pin 1: EMITTER]
                                    2N5401 (PNP)
  From Differential Input Stage ─►[Pin 2: BASE]
                                 [Pin 3: COLLECTOR]
                                        │
                                        ├───► Drive Signal to Driver / Output Stage (BD139 / BD140)
                                        │
                                 [ Constant Current Source / Active Load (2N5551) ]
                                        │
                            -45V Negative Supply Rail

Comparison: 2N5401 vs 2N3906 vs MPSA92

Parameter	2N3906	2N5401	MPSA92
$V_{CEO}$ Voltage	$-40\text{ V}$ (Low Voltage)	$-150\text{ V}$ (High Voltage)	$-300\text{ V}$ (Ultra High Voltage)
Max Current ( $I_C$ )	$-200\text{ mA}$	$-600\text{ mA}$	$-500\text{ mA}$
Transition Freq ( $f_T$ )	$250\text{ MHz}$	$100\text{ MHz} \dots 300\text{ MHz}$	$50\text{ MHz}$
Complementary NPN	2N3904	2N5551	MPSA42

Common mistakes

Treating as a low-voltage PNP (like 2N3906) for heavy current loads: While the 2N5401 withstands 150V, its maximum power dissipation in free air is $625\text{mW}$ . When dropping high voltages (e.g. $100\text{V}$ ) across the transistor, keeping current below $5\text{mA}$ is essential to avoid thermal destruction ( $P = 100\text{V} \times 5\text{mA} = 500\text{mW}$ ).
Overlooking polarity in PNP circuits: Remember that the Emitter of a PNP connects to the more positive voltage rail, and current flows out of the Base to turn the transistor ON.

Notes

Suffix Guide: 2N5401TA indicates ammo-pack tape through-hole packaging; MMBT5401 is the surface-mount SOT-23 equivalent.

Interface	Current-Driven Base Junction
Package	TO-92 Plastic (through-hole) / SOT-23 (MMBT5401)