onsemi PZTA27

Overview

PZTA27 from Fairchild Semiconductor is an NPN general-purpose amplifier transistor designed for high-current-gain linear amplification and switching up to 500 mA collector current. It features V_CEO = 60 V, h_FE ≥ 10,000 at I_C = 10 mA, V_CE(sat) = 1.5 V at I_C = 100 mA / I_B = 0.1 mA, and f_T = 125 MHz - used in low-noise preamplifier stages and relay driver circuits.

For engineers reviewing the PZTA27 datasheet, pinout, applications, or equivalent options, key selection considerations include its high h_FE stability across I_C = 1–500 mA, TO-92 and SOT-223 dual-package availability, thermal resistance (R_θJA = 125 °C/W in SOT-223), and compatibility with low-voltage base drive designs.

Technical Context

The PZTA27 operates as a silicon NPN bipolar junction transistor optimized for high DC current gain at medium collector currents. Its h_FE remains ≥10,000 from I_C = 10 mA to 100 mA under V_CE = 5 V, supporting stable biasing in Class-A amplifiers and saturated-switching configurations.

It supports continuous collector current up to 800 mA with V_CEO and V_CBO both rated at 60 V, and exhibits low leakage: I_CBO ≤ 100 nA at V_CB = 50 V. The device is characterized at T_A = 25°C with derating applied above that temperature per its R_θJA and R_θJC values.

Key Specifications

Pinout & Package

PZTA27 is available in two industry-standard packages: TO-92 (through-hole) and SOT-223 (surface-mount). Both share identical pin assignment: Pin 1 = Emitter, Pin 2 = Base, Pin 3 = Collector.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar NPN amplifier applications.

Compared with MPSA27 and ZTX653, the PZTA27 uniquely combines ultra-high h_FE, 60 V rating, and dual-package availability - making it optimal for gain-critical linear amplifiers where base drive efficiency and layout flexibility matter.

Availability

PZTA27 is available at Aetrix Electronics and suitable for audio preamplifier stages, relay driver circuits, linear voltage regulator pass elements, and signal-level shifter applications requiring stable component supply and long-term manufacturability.

Supply support for PZTA27 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

Fairchild Semiconductor was a U.S.-based semiconductor company specializing in power management, analog, and discrete components before its acquisition by ON Semiconductor in 2016.

The PZTA27 belongs to Fairchild's general-purpose bipolar transistor product line, engineered specifically for high-gain, medium-current amplification and switching in cost-sensitive industrial and consumer electronics.

FAQ

What is the maximum continuous collector current rating for PZTA27?

The PZTA27 has a maximum continuous collector current (I_C) rating of 800 mA at T_A = 25°C. Derating applies above this temperature per its thermal resistance specifications. In practice, sustained operation above 500 mA requires careful thermal management - especially in the SOT-223 package where P_D = 1000 mW and R_θJA = 125 °C/W define the safe operating area. The PZTA27 datasheet confirms this limit under Absolute Maximum Ratings.

Does PZTA27 have a guaranteed minimum h_FE value, and at what test conditions?

Yes, the PZTA27 guarantees a minimum h_FE of 10,000 at I_C = 10 mA and V_CE = 5.0 V, as specified in the Electrical Characteristics table. This high gain is maintained across a wide collector current range - also confirmed at I_C = 100 mA under identical V_CE. The PZTA27's h_FE specification directly supports low-base-drive amplifier and switching designs without external gain boosting.

What are the package options available for PZTA27, and how do their power ratings differ?

The PZTA27 is offered in both TO-92 and SOT-223 packages. The TO-92 version has P_D = 625 mW and R_θJA = 200 °C/W, while the SOT-223 version delivers P_D = 1000 mW and R_θJA = 125 °C/W. Both share identical pinout (Emitter-Base-Collector) and electrical characteristics. The PZTA27 SOT-223 variant is preferred for higher-power applications due to its superior thermal performance on standard FR-4 PCBs.

Is PZTA27 suitable for RF amplifier applications, and what is its frequency capability?

Yes, the PZTA27 is suitable for VHF-band RF amplifier applications due to its f_T = 125 MHz, measured at I_C = 10 mA and V_CE = 5.0 V. This transition frequency supports stable small-signal gain up to ~30 MHz in common-emitter configurations. While not optimized for UHF, the PZTA27's high h_FE and low noise make it appropriate for IF amplifiers, oscillator buffers, and low-power transmitter driver stages - all validated in the PZTA27 datasheet.

How does PZTA27 compare to MPSA27 in terms of electrical and packaging specifications?

The PZTA27 and MPSA27 share identical electrical characteristics - including V_CEO, h_FE, V_CE(sat), and f_T - because they originate from the same Fairchild die and process (Process 03). The key distinction is packaging: PZTA27 is qualified in both TO-92 and SOT-223, whereas MPSA27 is TO-92 only. Thus, the PZTA27 offers greater layout flexibility and higher power handling in surface-mount designs without compromising electrical performance.