Overview

The LA4820M compound power IC is designed for portable information processing equipment, such as electronic book players and personal notebook computers, and provides on chip headphone stereo amplifier and monaural speaker amplifier functions required of such devices. This system IC also provides on chip a power-saving headphone jack plug-in/out detection function, which automatically switches the amplifiers, and an optimum volume level controller.

Features

• Power-saving headphone jack plug-in/out detection function on chip that electronically switches between the stereo headphone amplifier and the monaural BTL amplifier according to jack plug-in/out.

• The monaural amplifier has, as output control functions, a built-in output limiter that permits adjustment in accordance with the speaker impedance and a non-clipping circuit that outputs a sine wave suited to the output D range, while the headphone amplifier has a built-in user-friendly PVSS (Peak Volume Select System).

• On-chip ripple filter with a high ripple rejection ratio in

order to reduce power line noise.

• Less external components needed thanks to system and circuit technology, and low-capacitance design (22 µF or less) allowing support for chip components.

Functions

• Monaural BTL power amplifier

• Headphone OCL power amplifier (16 Ω) × 2

• Output control functions: Headphone power PVSS Monaural power Non-clipping circuit and output limiter

• Headphone jack plug-in/out detection function (monaural amplifier/headphone amplifier switching)

• Ripple filter

• Power mute switch

• Common amplifier on/off switching