MMDT3946 / MMBT3946: Dual Complementary NPN + PNP Transistor in One Package

The MMDT3946 (same as MMBT3946) is a dual complementary transistor—one NPN and one PNP—housed in a compact SOT‑363 (SC‑88) surface‑mount package. Designed for low-power analog switching and amplification, this matched pair simplifies circuit designs by combining both transistor types in a single unit.

Key Features

Complementary Pair: One NPN (like MMBT3904/2N3904) + one PNP (like MMBT3906/2N3906) in one package
40 V voltage rating, supporting 200 mA collector current (each transistor)
Small‑signal switching and amplification at up to 300 MHz (fT)
Low Vce(sat), ideal for efficient switching
Ultra‑compact SOT‑363 (SC‑88) footprint for space‑constrained designs

Specifications

Parameter	Typical Value
Transistor Types	NPN + PNP complementary
Max Collector Current (Ic)	200 mA (each)
Max Collector-Emitter Voltage	40 V
Max Collector-Base Voltage	60 V
Max Emitter-Base Voltage	6 V
DC Current Gain (h_FE)	40–300 (varies with current)
Transition Frequency (f_T)	~300 MHz
Power Dissipation	~200 mW (total package)
Operating Temperature	–55 °C to +150 °C
Package	SOT‑363 (SC‑88), 6-pin

Applications

Push‑pull amplifier stages for efficient linear output
Voltage level shifting, inverters, and analog drivers
Signal conditioning where both polarities are needed (e.g., bidirectional level translators)
Complementary feedback pair (Sziklai pair) configurations for efficient drivers
Compact switch drivers and general‑purpose switching circuits

Functional Overview

Each transistor behaves like a typical discrete NPN and PNP.
The matched complementary layout ensures consistent performance and simplifies circuit designer effort by reducing BOM count.
Useful in designs where you need both polarities—for example, in push‑pull stages or polarity reversal.

Why Use MMDT3946?

Space-saving: Two transistors in one tiny package
Simplifies design: Ideal for push-pull stages or complementary switching
Electrical matching: Better thermal and performance stability
Cost-effective: Fewer components, easier layout, simpler assembly

The MMDT3946 / MMBT3946 is a true complementary transistor pair—one NPN and one PNP—optimized for analog and switching tasks where both polarities are needed. Compact, efficient, and matched, it's an excellent choice for space-sensitive designs or push-pull circuits such as amplifiers or level shifters.

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