NCP2824
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10
Table 4. NCP2824 CONFIGURATION
Pulse
Counting Register Description
01 AGC AGC disable
02 AGC Enable
03 Reset Reset configuration
04 Gain
Control
Gain = 12 dB
05 Gain = 18 dB
06 THD
Control
1%
07 2%
08 4%
09 6%
10 8%
11 10%
12 15%
13 20%
14 NC+L Non Clip + Power limit
15 NC Non Clip only
16 Power
Limit
Control
0.45 VPeak
17 0.9 VPeak
18 1.35 VPeak
19 1.8 VPeak
20 2.25 VPeak
21 2.7 VPeak
22 3.15 VPeak
23 3.6 VPeak
NOTE: The given values are typical for Vdd = 3.6 V and
TA = 25°C characterized
Built−in Low Pass Filter
This filter allows the user to connect a DAC or a CODEC
directly to the NCP2824 input without increasing the output
noise by mixing frequency with the DAC/CODEC output
frequency. Consequently, optimized operation with DACs
or CODECs is guaranteed without additional external
components.
Decoupling Capacitors
The NCP2824 requires a correct decoupling of the power
supply in order to guarantee the best operation in terms of
audio performances. To achieve optimum performance, it is
necessary to place a 4.7 mF low ESR ceramic capacitor as
close as possible to the VDD pin in order to reduce high
frequency transient spikes due to parasitic inductance (see
Layout considerations).
Input Capacitors Cin
Thanks to its fully differential architecture, the NCP2824
does not require input capacitors. However, it is possible to
use input capacitors when the differential source is not
biased or in single ended configuration. In this case it is
necessary to take into account the corner frequency which
can influence the low frequency response of the NCP2824.
The following equation will help choose the adequate input
capacitor.
fc+1
2@p@75 @103@Cin
Over Current Protection
This protection allows an over current in the H−Bridge to
be detected. When the current is higher than 2 A, the
H−Bridge is positioned in high impedance. When the short
circuit is removed or the current is lower, the NCP2824 goes
back to normal operation. This protection avoids over
current due to a bad assembly (Output shorted together, to
Vdd or to ground).
Layout Recommendations
For Efficiency and EMI considerations, it is strongly
recommended to use Power and ground plane in order to
reduce parasitic resistance and inductance.
For the same reason, it is recommended to keep the output
traces short and well shielded in order to avoid them to act
as antenna.
The level of EMI is strongly dependent upon the
application. However, ferrite beads placed close to the
NCP2824 will reduce EMI radiation when it is needed.
Ferrite value is strongly dependent upon the application.
Figure 17. Example of PCB Layout
Components Selection
To achieve optimum performance, one 4.7 mF 6.3 V X5R
should be used to bypass the power input supply (VDD).
Also particular care must be observed for DC−bias effects
in the ceramic capacitor selection. Smaller case−size and
higher DC bias voltage is preferred.
Some recommended capacitors include but are not limited
to:
4.7 mF 6.3 V 0603
TDK: C1608X5R0J475MT 0.95 mm max.