onsemi PZT3906

Overview

PZT3906 from onsemi is a PNP bipolar junction transistor (BJT) designed for general-purpose amplification and switching in low-to-medium power circuits, with −40 V V_CEO, −200 mA I_C, 1,000 mW P_D, h_FE = 100–300 at I_C = −10 mA, and SOT-223-4L package. It serves in discrete gain stages, level-shifting interfaces, and load-switching functions in industrial control and power management subsystems.

For engineers reviewing the PZT3906 datasheet, pinout, applications, or equivalent options, key selection criteria include its higher power dissipation versus TO-92/SOT-23 variants, thermal performance in PCB-mounted applications, PNP polarity compatibility with complementary NPN designs, and SOT-223 lead configuration for improved heat transfer in space-constrained layouts.

Technical Context

The PZT3906 operates as a single PNP BJT with fixed emitter-base-collector terminal arrangement and no integrated biasing or protection circuitry. Its DC current gain (h_FE) varies from 60 to 300 across collector currents from −0.1 mA to −100 mA, and saturation voltage remains ≤ −0.40 V at I_C = −50 mA / I_B = −5.0 mA.

Thermal design is defined by R_θJA = 125 °C/W on standard FR-4 PCB (76 mm × 114 mm), enabling operation up to +150 °C junction temperature. Switching behavior includes t_d/t_r = 35 ns and t_s = 225 ns under specified test conditions, supporting moderate-speed digital and analog signal control.

Key Specifications

Pinout & Package

SOT-223-4L package with exposed thermal pad (pin 4) for enhanced heat dissipation; molded plastic body, 4-terminal configuration, and standardized land pattern per JEDEC MO-178.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MMBT3906 and 2N3906, the PZT3906 delivers superior thermal performance and higher continuous power handling due to its SOT-223 package and integrated thermal pad-making it the preferred choice for production-grade industrial PCBs requiring long-term reliability under variable ambient conditions.

Availability

PZT3906 is available at Aetrix Electronics and suitable for industrial sensor interfaces, LED driver circuits, power supply enable control, and level-shifting interfaces requiring stable component supply across extended temperature ranges and multi-year production cycles.

Supply support for PZT3906 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, analog, sensing, and connectivity solutions for automotive, industrial, cloud, and consumer markets.

The PZT3906 belongs to onsemi's general-purpose bipolar transistor product line, engineered for cost-effective, reliable discrete amplification and switching in non-safety-critical industrial and commercial electronics.

FAQ

What is the maximum collector current rating for the PZT3906?

The PZT3906 has a maximum continuous collector current (I_C) rating of −200 mA at T_A = 25°C. This value decreases with rising ambient temperature due to thermal derating at 8.0 mW/°C above 25°C. The PZT3906 must be operated within this limit to avoid permanent damage or parametric shift, especially in high-density PCB layouts without forced airflow.

Does the PZT3906 have a built-in thermal pad, and how should it be connected?

Yes, the PZT3906 in SOT-223-4L package includes an exposed thermal pad (pin 4) electrically tied to the collector. It must be soldered to a minimum 100 mm² copper pour on the PCB for effective heat transfer. Leaving the pad unconnected degrades R_θJA from 125 °C/W to over 200 °C/W, risking thermal runaway under sustained load.

How does the PZT3906 compare to the MMBT3906 in terms of thermal performance?

The PZT3906 offers significantly better thermal performance than the MMBT3906: R_θJA is 125 °C/W versus 357 °C/W, and P_D is 1,000 mW versus 350 mW. This difference arises from the SOT-223 package's larger thermal pad and copper leadframe. As a result, the PZT3906 sustains higher collector currents without exceeding T_J(max) = 150°C in standard industrial PCB environments.

Can the PZT3906 be used as a direct replacement for the 2N3906 in existing TO-92 designs?

No, the PZT3906 is not a direct replacement for the 2N3906 due to incompatible packages: PZT3906 uses SOT-223-4L while 2N3906 uses TO-92-3L. Pinout differs (E-B-C vs E-B-C with thermal tab), and PCB layout, soldering profile, and thermal management must be redesigned. Electrical parameters are compatible, but mechanical integration requires redesign.

What is the typical noise figure of the PZT3906, and at what conditions is it measured?

The PZT3906 has a typical noise figure (NF) of 4.0 dB, measured at I_C = −100 μA, V_CE = −5.0 V, R_S = 1.0 kΩ, and frequency range 10 Hz to 15.7 kHz. This makes it suitable for low-noise preamplifier stages in sensor signal conditioning, though performance varies with operating point and external component selection.