ON Semiconductor’s ThermalTrak™ Devices Eliminate Thermal Lag and Bias Trimming in the Audio Output of High Fidelity Amplifiers


ThermalTrak™ output transistors with internal bias control eliminate amplifier warm-up period, enable instant temperature adjustment, upgrade sound quality and improve bias stability

International Consumer Electronics Showcase (CES) – Las Vegas, Nevada – Jan. 6, 2005 – Expanding its presence in the power audio components market, ON Semiconductor (NASDAQ: ONNN) today introduced ThermalTrak™ - a innovative family of output transistors with internal bias control that provide a simplified single-device solution for audio amplifier design. Featuring patent-pending technology, these devices eliminate tedious warm-up time, enable quick and precise temperature adjustment and improve both sound quality and bias stability. The initial devices will be ideal for use in high-end consumer audio amplifiers and receivers, as well as professional audio applications such as theater, stadium and PA sound systems. ThermalTrak™ devices simplify board design by eliminating the need for output drive compensation circuitry and costly manual bias adjustments.

“This new family of audio output devices provides a simplified, single-device design solution for audio amplifiers,” said Keith Nootbaar, ON Semiconductor director of Power Discrete products. “The soon-to-be patented ThermalTrakTM technology used to develop these devices enhances THD performance at lower power levels where it matters the most and will change the way audio amplifiers are designed. Additionally, this technology provides a platform upon which the company plans to build a significant portfolio of audio output power solutions.”

The Challenge
In audio output applications, transistor overheating leads to increased harmonic distortion and can potentially cause catastrophic failure of the end product. Designers have traditionally mounted discrete bias protection circuitry to the heat sink to monitor temperature changes. While relatively effective, this standard industry solution still results in a lag time before thermal stability is achieved. Ultimately, it can take up to 5 minutes for the temperature change of the heat sink to be significant enough to be recognized, creating the potential for thermal runaway of an individual transistor before any compensation is made.

The Solution
More accurate bias control is needed to overcome this design challenge and eliminate both the thermal lag and bias trimming. Rather than mounting bias transistor (or transistors) to the heat sink in close proximity to the output devices, ON Semiconductor’s ThermalTrak™ technology thermally integrates bias compensation within an output transistor. This provides precise detection and immediate correction of thermal changes - improving both sound quality and bias stability. This technology establishes a superior level of bias compensation performance not previously achievable using traditional discrete biasing circuitry.

The first ThermalTrak™ transistors to be introduced by ON Semiconductor are the NJL1302D (PNP) and the NJL3281D (NPN). These 230 volt (V) devices offer a 200 watt (W) power rating. Following the 200 W introduction, the company plans to introduce devices for 150 W and 250 W requirements. Further expansion of the ThermalTrak™ family for lower watt applications is planned for later 2005.

Packaging, Price and Availability
The NJL1302D and NJL3281D ThermalTrak™ devices will be offered in a standard size 5-lead, TO-264 package. The devices are budgetary priced at $2.25 per unit in 10,000 unit quantities. Limited advance engineering samples are currently available. The devices are scheduled for full production early in the second quarter. Send requests samples or additional information to ThermalTrak@onsemi.com. For additional technical information or to order samples email thermaltrak@onsemi.com.

About ON Semiconductor
ON Semiconductor (NASDAQ: ONNN) offers an extensive portfolio of power- and data-management semiconductors and standard semiconductor components that address the design needs of today’s sophisticated electronic products, appliances and automobiles. For more information visit ON Semiconductor’s web site at https://www.onsemi.com.

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ON Semiconductor and the ON Semiconductor logo are registered trademarks of Semiconductor Components Industries, LLC. All other brand and product names appearing in this document are registered trademarks or trademarks of their respective holders. Although the company references its Web site in this news release, such information on the web site is not to be incorporated herein.

About onsemi

onsemi (Nasdaq: ON) is driving disruptive innovations to help build a better future. With a focus on automotive and industrial end-markets, the company is accelerating change in megatrends such as vehicle electrification and safety, sustainable energy grids, industrial automation, and 5G and cloud infrastructure. With a highly differentiated and innovative product portfolio, onsemi creates intelligent power and sensing technologies that solve the world’s most complex challenges and leads the way in creating a safer, cleaner, and smarter world.


onsemi and the onsemi logo are trademarks of Semiconductor Components Industries, LLC. All other brand and product names appearing in this document are registered trademarks or trademarks of their respective holders. Although the Company references its website in this news release, information on the website is not to be incorporated herein.

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