AS1712 austriamicrosystems AG, AS1712 Datasheet - Page 10

• Manufacturer Part Number: AS1712
• Description: High-Output-Drive 10MHz 10V/us Rail-to-Rail I/O Op Amps
• Manufacturer: austriamicrosystems AG

AS1710/AS1712
Data Sheet - A p p l i c a t i o n I n f o r m a t i o n
60mW Single-Supply Stereo Headphone Driver
Two AS1710 amplifiers can be used as a single-supply, stereo headphone driver. The circuit shown in
deliver 60mW per channel with 1% distortion from a single 5V supply.
Figure 22. Stereo Headphone Driver Application (with Coupling Capacitor)
In
the high-pass filter is given by:
Choose gain-setting resistors R
put amplitude.
C
and the load impedance form a high-pass filter with the -3dB point determined by:
For a 32Ω load, a 100µF aluminum electrolytic capacitor gives a low-frequency pole at 50Hz.
Rail-to-Rail Input Stage
The AS1710/AS1712 CMOS op amps have parallel connected N- and P-channel differential input stages that combine
to accept a common-mode range extending to both supply rails. The N-channel stage is active for common-mode input
voltages typically greater than (V
cally less than (V
Rail-to-Rail Output Stage
The minimum output is within millivolts of ground for single- supply operation, where the load is referenced to ground
(V
lower. The maximum output voltage swing is load dependent although it is guaranteed to be within 500mV of the posi-
tive rail (V
www.austriamicrosystems.com
OUT
SS
Figure
).
blocks the DC component of the amplifier output, preventing DC current flowing to the load. The output capacitor
Figure 23
22, C
DD
= 2.7V) even with maximum load (32Ω to ground).
IN
shows the input voltage range and the output voltage swing of an AS1710 connected as a voltage fol-
DD
and R
- 1.2V).
IN
form a high-pass filter that removes the DC bias from the incoming signal. The -3dB point of
Audio In
Audio In
Right
Left
IN
SS
and R
+ 1.2V), and the p-channel stage is active for common-mode input voltages typi-
V
C
C
BIAS
IN
IN
F
according to the amount of desired gain, keeping in mind the maximum out-
f
-3dB
R
R
IN
IN
f
-3dB
= 1/(2
= 1/(2
Revision 1.06
π
–
+
+
–
AS1710
AS1710
R
π
LOAD
R
R
R
IN
F
F
C
C
IN
OUT
)
)
+
+
C
C
OUT
OUT
Headphone Jack
to 32Ω Stereo
Headset
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Figure 22
10 - 17
(EQ 4)
(EQ 5)
can