onsemi FJC1308QTF

Overview

FJC1308QTF from Fairchild Semiconductor is a PNP epitaxial silicon transistor designed for audio power amplifier stages, delivering high collector current (−3 A), low V_CE(sat) (−0.45 V at I_C = −1.5 A, I_B = −0.15 A), and robust breakdown ratings (V_CBO = V_CEO = −30 V). It serves as a complementary device to the NPN FJC1963 in push-pull output configurations.

For engineers reviewing the FJC1308QTF datasheet, pinout, applications, or equivalent options, key selection criteria include its SOT-89 package thermal performance, h_FE range (120–270), V_BE(sat) (−1.5 V), junction temperature limit (150°C), and suitability for Class AB audio output stages requiring stable DC gain and low saturation loss.

Technical Context

The FJC1308QTF operates as a medium-power PNP bipolar junction transistor optimized for linear amplification in audio output circuits. Its h_FE classification "Q" specifies DC current gain between 120 and 270 at V_CE = −2 V and I_C = −0.5 A, with guaranteed V_CE(sat) ≤ −0.45 V under forced β = 10 conditions.

Thermally, it uses the SOT-89 package with a 0.5 W power dissipation rating at T_C = 25°C and derates linearly above 25°C ambient, supporting operation up to 150°C junction temperature. Its low V_BE(sat) (−1.5 V) enables efficient base drive in complementary pair designs.

Key Specifications

Pinout & Package

Package: SOT-89 - surface-mount, 3-lead plastic package with exposed collector tab for thermal conduction to PCB copper.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar PNP power transistor applications.

Compared with MJD2955T4G and ZTX951, the FJC1308QTF offers the best balance of SMT compatibility, low saturation loss, and binned h_FE for compact audio output stages - making it optimal where thermal density, gain matching, and board area are jointly constrained.

Availability

FJC1308QTF is available at Aetrix Electronics and suitable for audio power amplifiers, DC motor drivers, LED current sinks, and linear regulator pass elements requiring stable component supply and consistent h_FE grading.

Supply support for FJC1308QTF 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 designer and manufacturer of analog and discrete semiconductors, acquired by ON Semiconductor in 2016; known for high-reliability power transistors and audio-grade components.

The FJC series targets cost-sensitive, high-volume audio and power linear applications, emphasizing manufacturable gain bins, repeatable saturation characteristics, and SOT-89 thermal performance for consumer and industrial amplifiers.

FAQ

What is the h_FE range for FJC1308QTF?

The FJC1308QTF is graded "Q", specifying a DC current gain (h_FE) range of 120 to 270 when measured at V_CE = −2 V and I_C = −0.5 A. This binning ensures predictable biasing in audio output stages and eliminates need for external gain-trimming components. The FJC1308QTF's h_FE remains stable across −40°C to 125°C per typical curves in the datasheet.

Is FJC1308QTF pin-compatible with other SOT-89 PNP transistors?

The FJC1308QTF uses standard SOT-89 pinout: Pin 1 = Base, Pin 2 = Collector (tab), Pin 3 = Emitter. While mechanically compatible with most SOT-89 PNP devices, electrical differences - especially h_FE, V_CE(sat), and I_C rating - require validation. The FJC1308QTF is not a drop-in replacement for generic SOT-89 PNP transistors without circuit-level verification.

What is the maximum power dissipation of FJC1308QTF at 70°C ambient?

At T_A = 70°C, the FJC1308QTF's maximum power dissipation is approximately 0.3 W, calculated using its 0.5 W rating at 25°C and 6.25 mW/°C derating slope (from Figure 6). This assumes adequate PCB copper area under the collector tab. Exceeding this risks junction temperature exceeding 150°C. The FJC1308QTF must be thermally anchored to maintain reliability in sustained-load applications.

Can FJC1308QTF replace FJC1308 in a design?

Yes - FJC1308QTF is the Q-grade variant of the FJC1308 family, differing only in h_FE bin (120–270 vs. ungraded or P/R bins). All absolute maximum ratings, package, pinout, and electrical test conditions are identical. The FJC1308QTF provides tighter gain control without layout or schematic changes, improving consistency in production audio amplifier builds.

Does FJC1308QTF support automotive temperature range?

The FJC1308QTF is specified for T_J = −55°C to +150°C and T_STG = −55°C to +150°C, meeting extended industrial temperature requirements. However, it is not AEC-Q101 qualified, and Fairchild's life support policy explicitly excludes use in safety-critical automotive systems. For non-safety automotive accessories (e.g., aftermarket audio), the FJC1308QTF may be used with full system-level qualification.