Description

The AS1702, AS1703, AS1704, and AS1705 are single channel differential audio power-amplifiers designed to drive 4Ω and 8Ω loads. The integrated gain circuitry of these amplifiers and their small size make them ideal for 2.7V to 5V powered portable audio devices.

The differential input design improves noise rejection and provides common-mode rejection. A bridge-tied load (BTL) design minimizes external component count, while providing Hi-Fi audio power amplification.

The devices deliver 1.8W continuous average power per channel to a 4Ω load with less than 1% total harmonic distortion (plus noise), while operating from a single 2.7V to 5V supply.

In order to facilitate reduced component designs, the devices are available with different gain levels:

•  AS1702 - Adjustable Gain (via external components)
•  AS1703 - AV = 0dB
•  AS1704 - AV = 3dB
•  AS1705 - AV = 6dB

Integrated shutdown circuitry disables the bias generator and amplifiers, and reduces quiescent current consumption to less than 100nA. The shutdown input can be set as active-high or active-low. All devices contain comprehensive click-and-pop suppression circuitry that reduces audible clicks and pops during power-up and shutdown.

The AS1702, AS1703, AS1704, and AS1705 are pin compatible with the LM4895 and the MAX9718A/B/C/D.

The devices are available in a 10-pin MSOP and 10-pin DFN package.

Following Demoboard are available:

• AS1702-1705 DemoKit

Key Features

•  2.7V to 5.5V (VCC) Single-Supply Operation
•  THD+N: 1.8W into 4Ω at 1% (per Channel)
•  Differential Input
•  Adjustable Gain Option (AS1702)
•  Internal Fixed Gain to Reduce External Component Count (AS1703, AS1704, AS1705)
•  <100nA Low-Power Shutdown Mode
•  Click and Pop Suppression
•  Pin-Compatible National Semiconductor LM4895 (AS1705) and Maxim MAX9718A/B/C/D
•  Operating Temperature Range: -40°C to +85°C
•  MSOP-10 and DFN-10 Package

Applications

The devices are ideal as audio Front Ends for battery powered audio devices such as MP3 and CD players, mobile phones, PDAs, portable DVD players, and any other hand-held battery-powered device.

Block diagram for AS1702 Audio Amplifier IC