onsemi TN6717A

Overview

TN6717A from Fairchild Semiconductor is an NPN general-purpose amplifier transistor designed for medium-power linear amplification and switching applications with continuous collector current up to 1.2 A, V_CEO = 80 V, and DC current gain (h_FE) of 80–250 at I_C = 50 mA, used in power supply control stages and audio preamplifier circuits.

For engineers reviewing the TN6717A datasheet, pinout, applications, or equivalent options, key selection criteria include its 80 V breakdown rating, 1.2 A continuous collector capability, SOT-223/TO-226 dual-package availability, thermal resistance of 125 °C/W (junction-to-ambient), and suitability for industrial DC-DC converter feedback loops and relay drivers.

Technical Context

The TN6717A operates as a silicon NPN bipolar junction transistor fabricated on Process 39, optimized for stable DC current gain across temperature (−55 °C to +150 °C) and low saturation voltage (V_CE(sat) = 0.35 V at I_C = 250 mA, I_B = 10 mA). Its f_T exceeds 100 MHz at I_C = 200 mA, supporting moderate-frequency switching.

It features low leakage (I_CBO ≤ 0.1 µA at V_CB = 60 V), tight V_BE(on) = 1.2 V at I_C = 250 mA, and safe operating area (SOA) defined for pulsed operation up to 100 µs, enabling robust performance in transient-loaded switching nodes.

Key Specifications

Pinout & Package

TN6717A is available in two industry-standard packages: TO-226 (also known as TO-92 variant TO-226AE) and SOT-223. Both packages feature three terminals - Collector (C), Base (B), Emitter (E) - with identical pin functional assignment but differing thermal and mounting characteristics.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MJD122G and BC817-40, the TN6717A offers balanced 80 V/1.2 A capability with dual-package flexibility (SOT-223 and TO-226), making it optimal for cost-sensitive industrial controls where moderate power, proven thermal behavior on standard PCBs, and legacy through-hole compatibility matter.

Availability

TN6717A is available at Aetrix Electronics and suitable for industrial motor drives, programmable logic controller (PLC) I/O modules, and isolated DC-DC converter feedback circuits requiring stable component supply with long lifecycle visibility.

Supply support for TN6717A 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 leading designer of discrete semiconductors and power management ICs, acquired by ON Semiconductor in 2016; its legacy bipolar transistor portfolio remains widely deployed in industrial and automotive systems.

The TN6717A belongs to Fairchild's general-purpose NPN amplifier family engineered for reliability in medium-power linear and switching roles, particularly in cost-sensitive industrial controls where thermal robustness and voltage margin are critical.

FAQ

What is the maximum continuous collector current rating for TN6717A?

The TN6717A has a maximum continuous collector current (I_C) rating of 1.2 A at T_A = 25 °C. This value decreases with rising ambient temperature due to thermal derating of 8 mW/°C above 25 °C. At 75 °C ambient, the usable I_C drops to approximately 0.8 A. The TN6717A must be mounted on FR-4 PCB with ≥6 cm² copper area on the collector pad to sustain full-rated current.

Does TN6717A support both TO-226 and SOT-223 packages?

Yes, TN6717A is offered in both TO-226 (TO-226AE, commonly called TO-92 variant) and SOT-223 packages, as confirmed by Fairchild's packaging documentation. Pinout is identical (C-B-E), but thermal resistance differs: R_θJA = 125 °C/W for both, while R_θJC = 50 °C/W applies only to the SOT-223 version. The TO-226 variant uses radial leadform and is supplied in bulk or tape-and-reel (D26Z/D27Z).

What is the typical DC current gain (h_FE) of TN6717A at different collector currents?

The TN6717A exhibits h_FE = 80–250 at I_C = 50 mA, V_CE = 1.0 V; h_FE = 50–250 at I_C = 250 mA; and h_FE = 20–250 at I_C = 500 mA. These ranges reflect process variation and ensure design margin for base drive calculation. The TN6717A maintains usable gain up to 1 A, supporting linear amplifier and high-current switch applications.

Can TN6717A be used in audio amplifier circuits?

Yes, TN6717A is suitable for low-to-mid frequency audio preamplifier stages due to its f_T > 100 MHz at I_C = 200 mA and low collector-base capacitance (C_cb = 30 pF), which minimize high-frequency phase shift and distortion. Its V_BE(on) = 1.2 V and stable h_FE support predictable biasing. The TN6717A is not intended for high-power output stages but excels in line-level gain blocks and sensor signal conditioning.

What is the safe operating area (SOA) limitation for pulsed operation of TN6717A?

The TN6717A SOA curve specifies pulsed operation limits: at 10 µs pulse width, it supports up to 10 A at V_CE = 10 V; at 100 µs, up to 3 A at V_CE = 40 V. These boundaries are defined for T_J ≤ 150 °C and assume proper PCB thermal design. Exceeding SOA risks second breakdown. The TN6717A datasheet provides graphical SOA plots referenced to pulse width and ambient temperature.