PAM8006A
15W Stereo Class-D Audio Power Amplifier with Power Limit
Differential Input
PLIMIT
The differential input stage of the amplifier
eliminates noises that appear on the two input
lines of the channel. To use the PAM8006A with a
differential source, connect the positive lead of
the audio source to the INP input and the negative
lead from the audio source to the INN input. To
use the PAM8006A with a single-ended source,
ac-ground the INP input through a capacitor equal
in value to the input capacitor on INN and apply
the audio source to the INN input. In a single-
ended input application, the INP input should be
ac-grounded at the audio source other than at the
device input for best noise performance.
The voltage at PL pin can used to limit the power
to levels below that which is possible based on
the supply rail. Add a resistor from PL to ground to
set the voltage at the PLIMIT pin. An external
reference may also be used if tighter tolerance is
required. Also add a 1uF capacitor fromPL pin to
ground. The PLIMIT circuit sets a limit on the
output peak-to-peak voltage. The gain of class D
amplifier will automatic reduced if the output
power higher than setting value to make output
power less than limited value and also provide
good sound quality.
The output power vs PL pin resistor value as
below.
Using low-ESR Capacitors
L o w - E S R c a p a c i t o r s a r e r e c o m m e n d e d
throughout this application section. A real (with
respect to ideal) capacitor can be modeled simply
as a resistor in series with an ideal capacitor. The
voltage drop across this resistor minimizes the
beneficial effects of the capacitor in the circuit.
The lower the equivalent value of this resistance
the more the real capacitor behaves as an ideal
capacitor.
VCC=12V,Rload=8Ω
R(Ω) PL (V) PL(W) R(Ω) PL (V) PL(W)
56K
62K
68K
75K
82K
91K
0.61
0.67
0.73
0.79
0.85
0.92
3.1
3.7
4.3
5.1
6.0
7.0
100K
110K
120K
130K
140K
0.99
1.07
1.15
1.22
1.36
8.1
9.0
9.6
10.0
10.7
Short-circuit Protection
The PAM8006A has short circuit protection
circuitry on the outputs to prevent damage to the
device when output-to-output shorts, output-to-
GND shorts, or output-to-VCCshorts occur. Once
a short-circuit is detected on the outputs, the
output drive is immediately disabled. This is a
latched fault and must be reset by cycling the
voltage on the SD pin to a logic low and back to
the logic high state for normal operation. This will
clear the short-circuit flag and allow for normal
operation if the short was removed. If the short
was not removed, the protection circuitry will
again activate.
Soft Clip
PAM Plimit
Hard Clip
Thermal Protection
Thermal protection on the PAM8006A prevents
damage to the device when the internal die
temperature exceeds 160°C. There is a ±15
degree tolerance on this trip point from device to
device. Once the die temperature exceeds the set
thermal point, the device enters into the shutdown
state and the outputs are disabled. This is not a
latched fault. The thermal fault is cleared once the
temperature of the die is reduced by 50°C. The
device begins normal operation at this point
without external system intervention.
Power Analog Microelectronics,Inc
10/2012 Rev1.0
www.poweranalog.com
12
PAM [ POWER ANALOG MICOELECTRONICS ]
