component
BD438
Public Made by Adomby adom
STMicroelectronics Bipolar (BJT), TO-126-3. Pinout cross-checked by two models against the datasheet, KiCad symbol/footprint/3D.
3D Model
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Symbol & Footprint
Schematic Symbol
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PCB Footprint
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Datasheet
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README
markdownBD438
STMicroelectronics · Bipolar (BJT) · TO-126-3
BD438 from STMicroelectronics, in a TO-126-3. Pinout and pin descriptions extracted from the manufacturer datasheet (extract_pins, cross-checked by a second model); symbol, footprint, and 3D from KiCad-official CAD.
Pinout
| Pin | Name | Type | Function |
|---|---|---|---|
| 1 | Base | input | Control input terminal with maximum base current of 1 A |
| 2 | Collector | output | Collector terminal with maximum collector current of 4 A and collector-emitter voltage of 45 V |
| 3 | Emitter | output | Emitter terminal with maximum emitter-base voltage of 5 V |
Key specifications
| Parameter | Value |
|---|---|
| Manufacturer | STMicroelectronics |
| Package | TO-126-3 |
| Category | Transistors/Thyristors |
| Pins | 3 |
Electrical characteristics
Limits as printed in the datasheet (page.json metadata.characteristics carries them as data).
| Parameter | Symbol | Min | Typ | Max | Unit | Conditions | Page |
|---|---|---|---|---|---|---|---|
| Collector-Base Voltage | VCBO | 45 | V | IE = 0; PNP BD438 column (datasheet note: PNP voltage/current values are negative) | 1 | ||
| Collector-Emitter Voltage | VCES | 45 | V | VBE = 0; PNP BD438 column (datasheet note: PNP voltage/current values are negative) | 1 | ||
| Emitter-Base Voltage | VEBO | 5 | V | IC = 0 | 1 | ||
| Collector Current | IC | 4 | A | 1 | |||
| Collector Peak Current | ICM | 7 | A | t ≤ 10 ms | 1 | ||
| Base Current | IB | 1 | A | 1 | |||
| Total Dissipation | Ptot | 36 | W | Tc ≤ 25 °C | 1 | ||
| Storage Temperature | Tstg | -65 | 150 | °C | 1 | ||
| Max. Operating Junction Temperature | Tj | 150 | °C | 1 | |||
| Thermal Resistance Junction-case Max | Rthj-case | 3.5 | °C/W | 2 | |||
| Thermal Resistance Junction-ambient Max | Rthj-amb | 100 | °C/W | 2 | |||
| Collector Cut-off Current (IE = 0) | ICBO | 100 | µA | for BD437/438 VCB = 45 V | 2 | ||
| Collector Cut-off Current (VBE = 0) | ICES | 100 | µA | for BD437/438 VCE = 45 V | 2 | ||
| Emitter Cut-off Current (IC = 0) | IEBO | 1 | mA | VEB = 5 V | 2 | ||
| Collector-Emitter Sustaining Voltage (IB = 0) | VCEO(sus) | 45 | V | IC = 100 mA for BD437/438; pulsed: pulse duration 300 µs, duty cycle 1.5 % | 2 | ||
| Collector-Emitter Saturation Voltage | VCE(sat) | 0.6 | V | IC = 2 A, IB = 0.2 A for BD437/438; pulsed: pulse duration 300 µs, duty cycle 1.5 % | 2 | ||
| Base-Emitter Voltage | VBE | 0.58 | V | IC = 10 mA, VCE = 5 V; pulsed: pulse duration 300 µs, duty cycle 1.5 % | 2 | ||
| Base-Emitter Voltage | VBE | 1.2 | V | IC = 2 A, VCE = 1 V for BD437/438; pulsed: pulse duration 300 µs, duty cycle 1.5 % | 2 | ||
| DC Current Gain | hFE | 30 | IC = 10 mA, VCE = 5 V for BD437/438; pulsed: pulse duration 300 µs, duty cycle 1.5 % | 2 | |||
| Matched Pair DC Current Gain Ratio | hFE1/hFE2 | 1.4 | IC = 500 mA, VCE = 1 V; pulsed: pulse duration 300 µs, duty cycle 1.5 % | 2 |
CAD (KiCad official)
- Symbol:
BD438 - Footprint:
Package_TO_SOT_THT:TO-126-3_Vertical - 3D model: TO-126-3 (KiCad packages3D, STEP)
- 3D model files:
bd438-etched.step/bd438-etched.glbcarry the MPN laser-etched on the die in a toggleableAdom.LaserEtchgroup (Fusion-ready);bd438.step/bd438.glbare the bare package body.
Provenance
Data extracted from the manufacturer datasheet, not a distributor listing:
- Datasheet: STMicroelectronics datasheet (4 pp, sha256
eff0c287adc6d211, retrieved 2026-09-24, tier: manufacturer) - Extractor: parts-factory
2.0.0/extract_pins 0.2, primaryclaude-haiku-4-5-20251001(text), consensusclaude-sonnet-5(agreed), guards: pin_guards 0.1: passed. Pins are checked against the footprint pad set and their cited datasheet pages before publish. - CAD: KiCad official libraries (CC-BY-SA 4.0).