Send an Inquiry

To receive a quote for your project, please fill in the following information, and we’ll get back to you promptly.

Submit Inventory List

Please fill in the following information, and we’ll get back to you promptly.

Home > Products > Discrete Semiconductor Products > Transistors > Bipolar (BJT) > Single Bipolar Transistors

STMicroelectronics BD436

Name: BD436
Brand: STMicroelectronics
SKU: BD436
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

Compare

Part No.:: BD436

Manufacturer:: STMicroelectronics

Category:: Single Bipolar Transistors

Package:: TO-225AA, TO-126-3

Datasheet:: BD436.pdf

Description:: TRANS PNP 32V 4A SOT-32-3

Quantity:: RFQ Add To RFQ list

Payment:

Shipping:

Inventory:4,381

Please send an inquiry. Send us your inquiry, and we will respond immediately.

Product details

Overview

BD436 from STMicroelectronics is a complementary PNP silicon power transistor in SOT-32 (TO-126) package, designed for medium-power linear and switching applications. It features V_CEO = –32 V, I_C = –4 A, P_tot = 36 W at T_c ≤ 25 °C, and h_FE ≥ 40 at I_C = 10 mA, and is commonly used as the PNP complement to BD435 in push-pull audio output stages.

For engineers reviewing the BD436 datasheet, BD436 pinout, BD436 application, or BD436 equivalent, key selection considerations include its negative polarity voltage/current ratings, thermal resistance (R_thj-case = 3.5 °C/W), saturation voltage (V_CE(sat) = –0.5 V @ I_C = –2 A), and matched pair gain consistency with BD435.

Technical Context

The BD436 operates as a medium-power PNP bipolar junction transistor with epitaxial base construction, optimized for linear amplification and hard-switching duty. Its absolute maximum ratings are defined with negative polarity: V_CBO = –32 V, V_CEO = –32 V, and I_C = –4 A, reflecting complementary symmetry with BD435.

Electrical behavior is characterized under case temperature control (T_case = 25 °C), with guaranteed h_FE ≥ 40 at low current (I_C = 10 mA, V_CE = 5 V) and ≥ 50 at medium current (I_C = 500 mA, V_CE = 1 V), supporting stable biasing in Class AB amplifier designs.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	–32 V - Maximum collector-emitter blocking voltage under open-base condition; defines safe operating area in switching mode
I_C	–4 A - Continuous DC collector current; sets upper limit for linear output stage conduction
P_tot	36 W - Total power dissipation at case temperature ≤ 25 °C; requires heatsink for sustained operation
V_CE(sat)	–0.5 V @ I_C = –2 A, I_B = –0.2 A - Low saturation voltage minimizes conduction loss in switching applications
h_FE	≥ 40 @ I_C = –10 mA, V_CE = –5 V - Ensures reliable base drive sizing for low-current bias networks
R_thj-case	3.5 °C/W - Junction-to-case thermal resistance; determines minimum heatsink requirement for thermal management

Pinout & Package

SOT-32 (TO-126) plastic package with molded epoxy body, intended for through-hole mounting and heatsink attachment via collector tab. Pin 1 = Base, Pin 2 = Collector (electrically connected to tab), Pin 3 = Emitter.

Pin/Terminal	Circuit Role	Design Meaning
1 (Base)	Control input terminal	Receives base current to regulate collector-emitter conduction; requires current-limiting resistor in driver stage
2 (Collector)	Main power output terminal	Electrically tied to metal tab; must be insulated from heatsink unless common collector configuration is used
3 (Emitter)	Current return path	Typically connected to supply rail in common-emitter configurations; defines reference for base bias network

Key Features

Feature	Design Value
Complementary pairing with BD435	Matched h_FE ratio ≤ 1.4 ensures balanced push-pull stage linearity and reduced crossover distortion
High f_T	3 MHz transition frequency supports audio-frequency amplification up to ~20 kHz with adequate gain margin
Low V_CE(sat)	–0.5 V at rated current reduces power loss and thermal stress in Class AB output stages
Robust SOA	Rated V_CEO(sus) = –32 V with pulse-tested sustaining capability enables reliable operation under inductive load switching

Applications

Car Radio Output Stage

DC Motor Driver Half-Bridge

Use Scenario: Medium-power audio amplifier output stage in automotive head units requiring ±32 V complementary devices.

IC Role / Device Role / Timing Role: PNP power switch in push-pull topology, paired with BD435 to deliver symmetrical positive/negative swing.

Use Value: Matched h_FE and identical V_CEO minimize quiescent current drift and thermal imbalance between NPN/PNP legs.

Use Scenario: High-side switch in brushed DC motor control circuits with flyback protection.

IC Role / Device Role / Timing Role: PNP high-side switch controlling motor supply connection; driven by NPN level-shifting stage.

Use Value: –32 V V_CEO rating accommodates back-EMF spikes up to 30 V during motor commutation.

Linear Power Supply Pass Transistor

Switch-Mode Power Supply (SMPS) Driver

Use Scenario: Series pass element in adjustable linear regulators delivering up to 3 A output current.

IC Role / Device Role / Timing Role: PNP series regulator transistor dissipating excess voltage as heat; mounted on heatsink.

Use Value: 36 W P_tot and 3.5 °C/W R_thj-case enable stable regulation at 5–10 V dropout with proper thermal design.

Use Scenario: Gate driver stage for external MOSFETs in low-frequency (<100 kHz) SMPS topologies.

IC Role / Device Role / Timing Role: PNP current amplifier boosting microcontroller GPIO output to drive MOSFET gate capacitance.

Use Value: –4 A I_C rating supports fast gate charging of >10 nF loads without saturation-induced delay.

Equivalent & Alternatives

The following parts are listed as comparable options for similar PNP power transistor applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
MJD44H11	V_CEO = –80 V, I_C = –8 A, P_tot = 30 W, TO-252 package	Higher voltage/current rating but lower power dissipation and surface-mount only	Preferred where higher breakdown margin is needed and PCB layout supports SMT thermal pads
BD438	V_CEO = –45 V, same package and pinout, h_FE ≥ 30 @ I_C = 10 mA	Higher voltage rating but lower DC gain at low current	Select when system supply exceeds 32 V and gain requirements permit trade-off

Compared with BD436, MJD44H11 offers greater voltage headroom and current capacity but requires rework for SMT assembly and delivers less power per watt due to lower P_tot; BD438 provides direct pin-compatible upgrade for 45 V systems but sacrifices low-current gain stability.

Availability

BD436 is available at Aetrix Electronics and suitable for car radio output stages, linear power supplies, DC motor drivers, and SMPS gate drivers requiring stable component supply and long-term industrial availability.

Supply support for BD436 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

STMicroelectronics is a global semiconductor leader headquartered in Geneva, designing and manufacturing analog, digital, and mixed-signal ICs and discrete components for industrial, automotive, and consumer markets.

The BD series was developed specifically for cost-sensitive, medium-power linear and switching applications in automotive audio and power conversion, emphasizing robustness, thermal performance, and complementary device matching.

FAQ

Is BD436 pin-compatible with BD434 and BD438?

Yes - all three share identical SOT-32 (TO-126) mechanical outline and pin assignment (Pin 1 = Base, Pin 2 = Collector, Pin 3 = Emitter). However, their absolute maximum ratings differ: BD434 is rated for –22 V, BD436 for –32 V, and BD438 for –45 V, so substitution requires verification of voltage stress margins.

What is the recommended heatsink interface for BD436?

BD436's collector is internally connected to the metal tab (Pin 2), requiring electrical isolation from the heatsink using mica or silicone washer plus thermal grease. Minimum recommended heatsink thermal resistance is ≤ 1.5 °C/W to maintain T_j ≤ 150 °C at full 36 W dissipation with 25 °C ambient.

Can BD436 be used in avalanche mode?

No - BD436 is not rated or characterized for controlled avalanche operation. Its V_CEO(sus) = –32 V is specified under pulsed conditions (300 µs, 1.5% duty cycle), but no energy-rated avalanche capability or ruggedness data is provided in the official datasheet.

How does BD436's h_FE vary with temperature?

h_FE increases with junction temperature: typical gain rises ~0.5%/°C above 25 °C. At T_j = 100 °C, h_FE is approximately 20–25% higher than room-temperature values, which must be accounted for in bias network stability analysis to avoid thermal runaway.

BD436 Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: TO-225AA, TO-126-3

Packaging:: Tube

Product Status:: Obsolete

Transistor Type:: PNP

Current - Collector (Ic) (Max):: 4 A

Voltage - Collector Emitter Breakdown (Max):: 32 V

Vce Saturation (Max) @ Ib, Ic:: 500mV @ 200mA, 2A

Current - Collector Cutoff (Max):: 100µA

DC Current Gain (hFE) (Min) @ Ic, Vce:: 40 @ 10mA, 5V

Power - Max:: 36 W

Frequency - Transition:: 3MHz

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: SOT-32-3

BD436 FAQ

1.How can I place an order for BD436 through Aetrix?

Please submit a Request for Quotation (RFQ) for BD436 on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for BD436 reliable?

The price and inventory of BD436 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BD436 is usually 5 days.

3.What payment methods are accepted for BD436?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BD436 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BD436?

BD436 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BD436 order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for BD436?

For technical support, including BD436 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BD436 requirements.

6.How does Aetrix verify that BD436 is sourced from the original manufacturer or authorized distributors?

All BD436 products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that BD436 meets industry standards.

7.What is the process for return or replacement of BD436?

All BD436 units undergo pre-shipment inspection (PSI). If there is an issue with BD436, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The BD436 part is unused and in its original packaging.

Return procedure for BD436:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

Tech Hub

2026-09-08 Obsolete Electronic Components: How to Source and Evaluate Replacements

A practical engineering and sourcing framework covering lifecycle verification, lifetime-buy calculations, replacement qualification, supplier checks and counterfeit-risk controls.

2026-09-07 TTL vs CMOS Logic Levels: 74HC and 74HCT Compatibility Explained

TTL and CMOS logic families differ in thresholds, loading, output drive, power and timing. This engineering guide compares 74HC and 74HCT, calculates noise margins and checks 3.3 V/5 V compatibility.

2026-09-04 Logic Level Shifter: How to Connect 3.3V and 5V Logic Safely

A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.

2026-09-03 74HC595 vs TPIC6B595: Output Drive, Pinout, Current, and Load Selection

The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…

2026-09-02 74HC595 Pinout, Timing, Output Current, and Applications

The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…

2026-09-01 Latch vs Flip-Flop: Timing, Differences and Design Choices

A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…

2026-08-30 D Latch Circuit: Truth Table, Timing, ICs and Applications

A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …

2026-08-28 SR Latch Explained: NOR and NAND Circuits, Truth Tables, and Applications

An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…

2026-08-27 Latch Circuit: SR and D Latches, Truth Tables, Timing, and Applications

Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…

2026-08-21 What Is an LED Driver? Types, Circuits, Dimming, and Selection

An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…