max9724c Maxim Integrated Products, Inc., max9724c Datasheet - Page 14

• Manufacturer Part Number: max9724c
• Description: Low Rf Susceptibility Directdrive Stereo Head- Phone Amplifier With 1.8v Compatible Shutdown
• Manufacturer: Maxim Integrated Products, Inc.

Low RF Susceptibility DirectDrive Stereo Head-
phone Amplifier with 1.8V Compatible Shutdown
To suppress this noise, and to provide a 2V
dard audio output level from a single 5V supply, the
MAX9724C can be configured as a line driver and
active lowpass filter. Figure 5 shows the MAX9724C
connected as 2-pole Rauch/multiple feedback filter with
a passband gain of 6dB and a -3dB (below passband)
cutoff frequency of approximately 27kHz (see Figure 6
for the Gain vs. Frequency plot).
Proper layout and grounding are essential for optimum
performance. Connect PGND and SGND together at a
single point on the PCB. Connect PVSS to SVSS and
bypass with a 1µF capacitor. Place the power-supply
bypass capacitor and the charge-pump hold capacitor
as close to the MAX9724 as possible. Route PGND and
all traces that carry switching transients away from
SGND and the audio signal path. The thin QFN pack-
age features an exposed pad that improves thermal
efficiency. Ensure that the exposed pad is electrical-
ly isolated from PGND, SGND, and V
exposed paddle to SVSS only when the board lay-
out dictates that the exposed pad cannot be left
floating.
For the latest application details on UCSP construction,
dimensions, tape carrier information, PCB techniques,
bump-pad layout, and recommended reflow tempera-
ture profile, as well as the latest information on reliability
testing results, refer to the Application Note UCSP—A
Wafer-Level Chip-Scale Package available on Maxim’s
website at www.maxim-ic.com/ucsp.
14
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UCSP Applications Information
Layout and Grounding
DD
. Connect the
RMS
stan-
Figure 6. Frequency Response of Active Filter of Figure 4
-10
-15
-20
-25
-30
-35
10
-5
5
0
1k
MAX9724C ACTIVE FILTER GAIN
vs. FREQUENCY
10k
FREQUENCY (Hz)
100k
R
L
= 10kΩ
1M