Three new stereo audio amplifiers lm4780, lm4781 and lm4782 introduced by national semiconductor are used in home stereo system. This latest audio amplifier has a fade in / fade out mute mode circuit that gradually increases or decreases the sound. These “nice ears” transients enhance the auditory enjoyment in small stereo, high definition television (HDTV), 5.1 surround sound system and other consumer electronic devices.

Performance characteristics and application of stereo system amplifier lm4780 / 1 / 2

Lm4780 is a stereo audio amplifier, each channel can provide 60W continuous average output power, lm4781 is a three channel audio amplifier, each channel can provide 35W continuous average output power to 8 ohm load, and lm4782 is a three channel audio amplifier, each channel can provide 25W continuous average output power to 8 ohm load. The total distortion plus noise (THD + n) of all three products is less than 0.5% in the frequency range of 20Hz-20KHz

The lm4780 / 81 / 82 audio amplifier is completely controlled by the self peak instantaneous temperature (° Ke) (spike?) of national Protection circuit. Spike? The circuit provides a dynamically optimal safe working area. Spike? The protection circuit completely protects the output of lm4780 / 81 / 82 from overvoltage, undervoltage, overload, short circuit to power or ground, thermal deviation and instantaneous temperature peak. The advanced protection characteristics of lm4780 / 81 / 82 audio amplifier are unique in discrete and hybrid amplifiers. Lm4780 / 81 / 82 audio amplifier can be easily configured to work in bridge or parallel, For greater power and dual amplifier solutions. All three audio amplifiers have separate smooth fade / fade mute. In addition, the lm4782 has a power saving standby mode. Mute and standby modes are controlled by external logic signals.

Lm4780, lm4781 and lm4782 are 27 pin TO-220 packages

Responsible editor: GT

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