Power Transistor BD646 PNP Darlington, TO-220

Power Transistor BD646 PNP Darlington, TO-220

Transistors

Reference: TRBD646

Part.No: BD646

€1.40

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The BD646 is a PNP Darlington transistor in a TO-220 package, engineered for high-current switching and motor control applications. Its internal Darlington configuration delivers exceptional current gain, enabling direct load driving from weak logic signals.

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Description
Product Details

BD646 PNP Darlington Transistor – High-Gain Power Switching for Motors & Relays

The BD646 is a PNP Darlington transistor in TO-220 package, ideal for applications requiring high current gain and robust power switching. Its Darlington configuration minimizes base current requirements, making it perfect for driving relays, motors, and solenoids directly from microcontroller or logic IC outputs.

Functions & Applications

Darlington Configuration: Exceptional current gain (high hFE) enables driving large loads from minimal base current.
Power Handling: TO-220 package with integrated mounting tab for easy heatsink attachment at high currents.
Motor & Relay Control: Perfect for H-Bridges, PWM motor drivers, and relay switching circuits.
Direct Logic Compatibility: Easily driven from 5V microcontroller outputs and logic IC pins.

Technical Specifications

Parameter	Value / Specification
Transistor Type	Darlington
Polarity / Channel	PNP
Package / Case	TO-220
Collector-Emitter Voltage (Vceo)	−100V
Max Collector Current (Ic)	10A
Power Dissipation (Pd)	40W (with heatsink)
Saturation Voltage (Vce_sat)	1.5–2V
Mounting Type	Through-Hole with Mounting Tab (TO-220)

Frequently Asked Questions

Q: Does the BD646 require a heatsink?
A: At currents above 2–3A, a heatsink is strongly recommended due to the higher saturation voltage drop (1.5–2V) inherent to Darlington transistors, which generates significant heat.

Q: What is the complementary NPN Darlington part?
A: The complementary NPN Darlington is the BD645, offering identical characteristics in opposite polarity for symmetric push-pull or H-Bridge designs.

Notes

Darlington configuration results in higher saturation voltage (1.5–2V) and reduced switching speed compared to standard BJTs. Essential for high-current applications; always use with appropriate heatsink and flyback diodes on inductive loads.

Note: Price refers to one (1) piece. The component is shipped in bulk without individual packaging.

Transistor Type: Darlington
Transistor Polarity / Channel: PNP
Transistor Case Style: TO-220

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