onsemi MMBT3906-G

Overview

MMBT3906-G from onsemi is a PNP bipolar junction transistor (BJT) designed for general-purpose amplification and switching at collector currents from 10 mA to 100 mA. It features V_CEO = −40 V, I_C = −200 mA continuous, h_FE = 100 (at I_C = −10 mA), V_CE(sat) = −0.25 V (at I_C = −10 mA / I_B = −1 mA), and f_T = 250 MHz - enabling use in low-voltage logic-level interface circuits, discrete amplifier stages, and load-switching applications.

For engineers reviewing the MMBT3906-G datasheet, pinout, applications, or equivalent options, key selection considerations include its SOT-23 package footprint, PNP polarity, thermal derating (2.8 mW/°C above 25°C), and verified performance across −55°C to +150°C operating range - critical for space-constrained industrial control and automotive body electronics designs.

Technical Context

The MMBT3906-G operates as a discrete PNP BJT with fixed current gain characteristics dependent on collector current and temperature. Its DC current gain (h_FE) ranges from 60 at I_C = −0.1 mA to 30 at I_C = −100 mA, and saturation voltage rises predictably with current - V_CE(sat) = −0.40 V at I_C = −50 mA / I_B = −5 mA.

Small-signal behavior includes f_T = 250 MHz at I_C = −10 mA / V_CE = −20 V, C_obo = 4.5 pF at V_CB = −5 V, and NF = 4.0 dB at I_C = −100 μA - confirming suitability for audio-frequency amplification and moderate-speed digital switching up to ~50 MHz.

Key Specifications

Pinout & Package

SOT-23 3-lead plastic surface-mount package (JEDEC TO-236AB), 1.30 mm × 2.92 mm footprint, 1.20 mm max height, with gull-wing leads for reflow soldering. Pin 1 = Emitter, Pin 2 = Base, Pin 3 = Collector - confirmed by onsemi Figure 18 and marking "2A" orientation.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar PNP general-purpose amplifier applications.

Compared with MMBT3906-G, MMBT3906LT1G offers identical performance in a RoHS-optimized manufacturing flow, while PN2907A trades miniaturization for higher current headroom and thermal mass - making MMBT3906-G optimal for space-constrained, high-density SMT designs needing proven reliability at 10–100 mA loads.

Availability

MMBT3906-G is available at Aetrix Electronics and suitable for LED driver circuits, level-shifting interfaces, low-power audio preamps, and relay coil drivers requiring stable component supply across industrial automation, automotive body electronics, and consumer IoT device programs.

Supply support for MMBT3906-G 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

onsemi (formerly ON Semiconductor) is a global semiconductor supplier specializing in energy-efficient power and sensing solutions for automotive, industrial, cloud, and edge applications.

The MMBT3906-G belongs to onsemi's general-purpose bipolar transistor product line, engineered for cost-sensitive, high-reliability discrete switching and amplification in consumer, computing, and industrial systems.

FAQ

What is the maximum continuous collector current rating for the MMBT3906-G?

The MMBT3906-G has a maximum continuous collector current (I_C) rating of −200 mA at T_A = 25°C. This value decreases linearly with ambient temperature at 2.8 mW/°C derating, reaching approximately −140 mA at 85°C ambient on a standard FR-4 PCB - a key constraint for sustained switching in enclosed enclosures.

Does the MMBT3906-G have a documented pinout configuration for SOT-23 package?

Yes, the MMBT3906-G uses standard SOT-23 pinout: Pin 1 = Emitter, Pin 2 = Base, Pin 3 = Collector - confirmed in onsemi's official datasheet (PZT3906/D, Rev. 2, Figure 18). The top-mark "2A" aligns with this orientation, and the device is not pin-compatible with SOT-23 NPN variants like MMBT3904-G due to reversed polarity.

What is the typical DC current gain (h_FE) of the MMBT3906-G at 10 mA collector current?

The MMBT3906-G exhibits a typical DC current gain (h_FE) of 100 at I_C = −10 mA and V_CE = −1.0 V, with a guaranteed minimum of 60 across the −55°C to +150°C range. This value drops to 30 at I_C = −100 mA, requiring careful bias design for high-current linear operation.

Can the MMBT3906-G be used in audio-frequency amplifier stages?

Yes, the MMBT3906-G is suitable for audio-frequency amplification, with measured noise figure (NF) of 4.0 dB at I_C = −100 μA and f = 1 kHz, and f_T = 250 MHz ensuring flat gain response up to 20 kHz. Its low V_CE(sat) and stable h_FE support Class-A preamp designs in battery-powered microphones and sensor signal conditioning.

What is the thermal resistance (R_θJA) of the MMBT3906-G in its SOT-23 package?

The MMBT3906-G has a junction-to-ambient thermal resistance (R_θJA) of 357 °C/W when mounted on a standard FR-4 PCB per onsemi's test conditions (76 mm × 114 mm × 1.57 mm). This means a 100 mW power dissipation raises junction temperature by ~36°C above ambient - critical for reliability validation in sealed enclosures.