AS1702_1 AMSCO [austriamicrosystems AG], AS1702_1 Datasheet - Page 11

• Manufacturer Part Number: AS1702_1
• Description: 1.8W Single-Channel Audio Power Amplifiers
• Manufacturer: AMSCO [austriamicrosystems AG]

AS1702 - AS1705
Data Sheet
8 Detailed Description
The AS1702 - AS1705 are 1.8W high output-current audio amplifiers (configured as BTL amplifiers), and contain inte-
grated low-power shutdown and click- and pop-suppression circuitry. Two inputs (SHDM and SHDN) allow shutdown
mode to be configured as active-high or active-low
Each device has either adjustable or fixed gains (0dB, 3dB, 6dB)
Bias
The devices operate from a single 2.7 to 5.5V supply and contain an internally generated, common-mode bias voltage
of:
referenced to ground. Bias provides click-and-pop suppression and sets the DC bias level for the audio outputs. Select
the value of the bias bypass capacitor as described in
Note: Do not connect external loads to BIAS as this can adversely affect overall device performance.
Shutdown Mode
All devices implement a 100nA, low-power shutdown circuit which reduces quiescent current consumption. As shut-
down mode commences, the bias circuitry is automatically disabled, the device outputs go high impedance, and bias is
driven to GND.
The SHDM input controls the polarity of SHDN:
Table 6. Shutdown Mode Selection Configurations
Click-and-Pop Suppression
During power-up, the device common-mode bias voltage (V
ing shutdown, the device outputs are driven high impedance to 100kΩ between both outputs minimizing the energy
present in the audio band, thus preventing clicks and pops.
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SHDM
Drive SHDM high for an active-low SHDN input.
Drive SHDM low for an active-high SHDN input.
0
0
1
1
- D e t a i l e d D e s c r i p t i o n
SHDN
0
1
0
1
Normal Operation Enabled
Normal Operation Enabled
Shutdown Mode Enabled
Shutdown Mode Enabled
Mode
(see Shutdown Mode on page
Revision 1.47
Section BIAS Capacitor on page
V
2
CC
BIAS
(see page
(see Ordering Information on page
4)) ramps to the DC bias point. When enter-
11).
15.
19).
(EQ 1)
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