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NATIONAL SEMICONDUCTOR'S OVERTURE® AUDIO POWER AMPLIFIER FAMILY NOW AVAILABLE IN AN ELECTRICALLY ISOLATED TO-220 PACKAGE

Low Thermal Gradient ((theta)jc =1.6degrees C/W)

Saves Manufacturing Time by Eliminating Electrically Insulative Washers

Reduces Cost of Materials & Assembly

Provides Inherent Safety During Manufacturing

No Loss in Overall System Thermal Performance

Nov 30, 1995

SANTA CLARA, CA., November 30, 1995 - A TO-220 package offering complete electrical isolation without insulative washers and with no degradation of thermal performance has been developed by National Semiconductor. The new IC package is designed to house National's Overture® audio power monolithic amplifiers, which are used to drive loudspeakers in televisions, mini-components and home theater audio products.

"Eliminating the insulating washer alone makes this power package attractive to designers," noted Todd Moore, National's strategic marketing engineer. "An even more compelling reason to use this package is the inherent safety and subsequent protection of the device from shorts during system manufacturing."

National's new package design eliminates the need for placing mica washers or other insulating material between the package's lead frame and heat sink, a configuration routinely used for applications using split supply voltage (V+ and V-). Standard TO-220 dimensions are retained in the National design, with the exception of a thin overmolding surrounding the heat tab.

National's isolated TO-220 package provides a thermal gradient ((theta)jc) equal to 1.6degrees C/Watt, which is nearly equivalent to a non-isolated package. With the elimination of the insulative washer, system thermal dissipation is virtually unchanged. Eleven-lead and fifteen-lead packages are currently available, with additional configurations expected. All of National's Overture audio amps are available in this package including the LM1876TF, LM4700TF, LM2876TF, LM3875/6TF and LM3886TF, ranging from 20 to 68 watts, continuous power.