AS1704 austriamicrosystems, AS1704 Datasheet - Page 15

• Manufacturer Part Number: AS1704
• Description: IC AMP AUDIO MONO 1.8W 10-MSOP
• Manufacturer: austriamicrosystems
• Type: Class ABr

Specifications of AS1704

• Output Type: 1-Channel (Mono)
• Max Output Power X Channels @ Load: 1.8W x 1 @ 4 Ohm
• Voltage - Supply: 2.7 V ~ 5.5 V
• Features: Depop, Differential Inputs, Short-Circuit and Thermal Protection, Shutdown
• Mounting Type: Surface Mount
• Package / Case: 10-MSOP, Micro10™, 10-uMAX, 10-uSOP
• No. Of Channels: 1
• Output Power: 1.8W
• Supply Voltage Range: 2.7V To 5.5V
• Load Impedance: 4ohm
• Operating Temperature Range: -40°C To +85°C
• Amplifier Case Style: MSOP
• No. Of Pins: 10
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

AS1702 - AS1705
Data Sheet
Input Filter
The BTL inputs can be biased at voltages other than mid-supply. However, the integrated common-mode feedback cir-
cuit adjusts for input bias, ensuring the outputs are still biased at mid-supply. Input capacitors are not required if the
common-mode input voltage (V
Input capacitor C
ing signal. The AC coupling capacitor allows the amplifier to bias the signal to an optimum DC level. Assuming zero-
source impedance, the -3dB point of the high-pass filter is given by:
Setting f
age coefficients such as tantalum or aluminum electrolytic should be used, since capacitors with high-voltage coeffi-
cients, such as ceramics, can increase distortion at low frequencies.
BIAS Capacitor
BIAS is the output of the internally generated V
and THD+N by reducing power supply noise and other noise sources at the common-mode bias node, and also gener-
ates the click- and pop-less DC bias waveform for the amplifiers. Bypass BIAS with a 0.1µF capacitor to GND. Larger
values of C
t
Note: Do not connect external loads to BIAS.
Supply Bypassing
Proper power supply bypassing – connect a 10µF ceramic capacitor (C
low-distortion performance of the device. Additional bulk capacitance can be added as required.
Note: Place C
Layout and Grounding Considerations
Well designed PC board layout is essential for optimizing device performance. Use large traces for the power supply
inputs and amplifier outputs to minimize losses due to parasitic trace resistance and route heat away from the device.
Good grounding improves audio performance and prevents digital switching noise from coupling onto the audio signal.
www.austriamicrosystems.com
ON
/t
OFF
-3dB
by 10 and improves PSRR by 20dB (at 1kHz).
BIAS
too high affects the low-frequency response of the amplifier. Capacitors with dielectrics that have low-volt-
- A p p l i c a t i o n I n f o r m a t i o n
(up to 1µF) improve PSRR, but increase t
BIAS
IN
(if used), in conjunction with R
as close to the device as possible.
IC
) is within the range specified in
CC
IN
/2 bias voltage. The BIAS bypass capacitor, C
f
-3dB
, forms a high-pass filter that removes the DC bias from an incom-
Revision 1.47
=
ON
2
π
/t
R
OFF
1
IN
C
times. For example, a 1µF C
IN
Table 4
BIAS
and
) from V
Table
CC
5.
to GND – will ensure low-noise,
BIAS
BIAS
capacitor increases
, improves PSRR
(EQ 8)
15 - 20