ON Semi Extends ThermalTrak to Include Audio Amps

ON Semiconductor added a new family of ThermalTrak™ output transistors with the unique feature of internal bias control. Designed for use in both high-end and cost-competitive consumer audio applications, and high-power professional sound systems, the ThermalTrak™ devices improve overall sound quality and simplify design.

The patented ThermalTrak™ technology utilized in ON Semiconductor's audio output transistors works to eliminate warmup time, and enables quick and precise bias adjustment. Real-time temperature sensing allows designers to monitor operating temperatures more accurately, and works to improve both sound quality and bias stability. By eliminating the need for output drive compensation circuitry and manual bias adjustments, the devices greatly simplify amplifier design.

"ThermalTrak™ has changed how designers implement power audio amplification," said Mike Paquette, director of ON Semiconductor's Power Discrete product group. "Typical bias schemes often require a designer to slightly under-bias amplifier output devices so that thermal runaway does not occur. This prevents the amplifier from achieving true high-fidelity performance. Put simply, ON Semiconductor's ThermalTrak™ output transistors are single-device solutions that enable true high-fidelity performance."

The medium frequency NJL21193DG (PNP) and the NJL21194DG (NPN) are 250 V devices that offer a 200 watt (W) power rating and a 4 MHz bandwidth. The power rating and safe operating area (SOA) of these devices make them suited for high-power professional audio applications that require high reliability. Such applications include professional sound reinforcement and large venue PA sound systems.

The high power and gain matching of these devices are also important in consumer audio amplifiers and professional audio applications that use either single or multiple paralleled output devices. Such applications include car audio, home stereo and home theater systems.

The ThermalTrak™ devices are offered in a standard size 5-lead, TO-264 package. The new medium frequency NJL21193DG and NJL21194DG devices are budgetary priced at $1.60 per unit. The NJL0302DG and NJL0281DG (30 MHz, 180 W devices) are budgetary priced at $1.30 per unit. The NJL4302DG and NJL4281DG (30 MHz, 250 W devices) and the NJL1302DG and NJL3281DG (30 W, 200 W devices) are budgetary priced at $1.75 per unit. All these prices are based on 10,000 unit quantities.