AS1701_1 AMSCO [austriamicrosystems AG], AS1701_1 Datasheet - Page 10

• Manufacturer Part Number: AS1701_1
• Description: 1.6W Audio Power Amplifiers
• Manufacturer: AMSCO [austriamicrosystems AG]

AS1701, AS1706
Data Sheet
8 Detailed Description
The AS1701/AS1706 bridged audio power-amplifiers can deliver 1.6W into 4 Ω while operating from a single 2.7 to
5.5V supply. The devices consist of two high-output-current operational amplifiers configured as a bridge-tied load
(BTL) amplifier as shown in
Figure 29. AS1701 Typical Configuration Block Diagram
The gain of the devices is set by the closed-loop gain of the input operational amplifier. As shown in
put of the first amplifier serves as the input to the second amplifier, which is configured as an inverting unity-gain fol-
lower in both devices. This results in two outputs, identical in magnitude, and 180° out-of-phase.
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. For
selection of the value for the bias bypass capacitor (C
nally connected to the non-inverting input of one amplifier, and should be connected to the non-inverting input of the
other amplifier for proper signal biasing
Shutdown
The integrated 100nA, low-power shutdown circuitry reduces quiescent current consumption. As shutdown com-
mences, the bias circuitry is automatically disabled, the device outputs go high impedance, and bias is driven to GND.
Note:
Current Limit
The AS1701/AS1706 current limit circuitry protects the device during output short-circuit and overload conditions.
When both amplifier outputs are shorted to either V
enters a pulsing mode, reducing the average output current to a safe level. The amplifier remains in this mode until the
short-circuit or overload condition is corrected.
www.austriamicrosystems.com
Audio
Input
Connect SHDN to GND for the AS1701 (active-high); connect SHDN to V
0.33µF
- D e t a i l e d D e s c r i p t i o n
C
IN
1.0µF
0.1 to
20kΩ
R
20kΩ
IN
+
C
SHDN
Figure
B
BIAS
R
IN+
F
IN-
29.
(see Figure
+
–
Bias
DD
29).
V
Revision 1.52
0.1µF
BIAS
DD
or GND, the short-circuit protection is enabled and the amplifier
/2
+
), see
V
GND
50kΩ
50kΩ
DD
C
S
/2
V
DD
Bias Bypass Capacitor on page
V
DD
40kΩ
40kΩ
AS1701
–
+
Av = -1
DD
for the AS1706 (active-low).
13. Pin BIAS is inter-
OUT+
OUT-
Figure
29, the out-
4 or 8Ω
R
L
10 - 17
(EQ 1)