a us t ria
m i c r o
s y s t e m s
AS1702, AS1703, AS1704, AS1705
1.6W Single-Channel Audio Power Amplifiers
D a ta S he e t
1 General Description
The AS1702, AS1703, AS1704, and AS1705 are single-
channel differential audio power-amplifiers designed to
drive 4 and 8Ω loads. The integrated gain circuitry of
these amplifiers and their small size make them ideal for
2.7- 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 1.6W continuous average power per
channel to a 4Ω load with less than 1% total harmonic
distortion (plus noise), while operating from a single 2.7
to 5V supply.
In order to facilitate reduced component designs, the
devices are available with different gain levels:
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2 Key Features
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2.7 to 5.5V (V
CC
) Single-Supply Operation
THD+N: 1.6W 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 to +85°C
Low-Cost MSOP-10 Package
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AS1702 – Adjustable Gain (via external components)
AS1703 – A
V
= 0dB
AS1704 – A
V
= 3dB
AS1705 – A
V
= 6dB
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Integrated shutdown circuitry disables the bias genera-
tor and amplifiers, and reduces quiescent current con-
sumption 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 package.
Figure 1. Simplified Block Diagram
3 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.
Single Supply
2.7 to 5.5V
IN+
+
OUT+
IN-
–
OUT-
R
L =
4 or 8Ω
SHDN
SHDM
AS1702, AS1703,
AS1704, AS1705
GND
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