TFA9812HN PHILIPS [NXP Semiconductors], TFA9812HN Datasheet - Page 22

• Manufacturer Part Number: TFA9812HN
• Description: BTL stereo Class-D audio amplifier with I2S input
• Manufacturer: PHILIPS [NXP Semiconductors]

NXP Semiconductors
TFA9812_2
Preliminary data sheet
8.5.6 Output power limiter
8.5.7 PWM control for performance improvement
Table 17.
The I
pin has no function In I
The TFA9812 features also specific gain settings which are related to < 0.5 %, 10 %, 20 %
or 30 % clipping at the output of the TFA9812. These clipping values are only valid under
the following conditions:
The I
mode the clip level is set to 10 %.
Output power can be limited to three discrete levels with respect to the maximum power.
The maximum power output value is determined by the value of the high voltage supply.
Clipping levels (see
voltage swings.
In I
Section
limit level as shown in
Table 18.
The PWM switching frequency of the TFA9812 is dependent on:
Equation 9
frequency:
GAIN pin value
0
1
Pin value
ADSEL2/PLIM2
0
0
1
1
f
•
•
•
•
•
•
sw
2
The volume control is set to 0 dB.
The gain boost is set to 0 dB.
A 0 dBFs I
C control mode the same output power limiting levels can be selected, see
The sampling frequency, f
The sampling frequency setting, f
The PWM switching frequency setting, f
=
2
2
C controls for selecting the +24 dB gain can be found in
C controls for selecting a specific clip level can be found in
--------------------------- - f
f
9.5.6. In Legacy control mode two pins can be used to select the output power
s selected
GAIN pin functionality
Legacy mode output power limiter control
shows the relationship between these settings and the PWM carrier
f
s
2
S input signal is obtained.
Section
sw selected
Rev. 02 — 22 January 2009
Table
2
C mode.
8.5.5) still apply to the maximum levels of reduced output
18.
s
ADSEL1/PLIM1
0
1
0
1
.
BTL stereo Class-D audio amplifier with I
s
(selected) (see
sw
Function
0 dB gain
+24 dB gain
(selected) (see
Section
Function
Maximum power
Maximum power
Maximum power
Maximum power
Section
9.5.7).
Section
Section
9.5.6).
9.5.6. The GAIN
© NXP B.V. 2009. All rights reserved.
TFA9812
9.5.6. In Legacy
1.5 dB
3.0 dB
4.5 dB
2
S input
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