Diodes PAM8012 - Manual (Page 7)

PAM8012
Document number: DSxxxxx Rev. 1 - 3
7 of 14
www.diodes.com
October 2012
© Diodes Incorporated
PAM8012
A Product Line of
Diodes Incorporated
Application Information
Test Setup for Performance Testing
Notes: 1. The AP AUX-0025 low pass filter is necessary for class-D amplifier measurement with AP analyzer.
2. Two 33μH inductors are used in series with load resistor to emulate the small speaker for efficiency measurement.
Anti-Saturation
The Anti-saturation feature provides continuous automatic gain adjustment to the amplifier through an internal circuit. This feature enhances the
perceived audio loudness and at the same time prevents speaker damage from occurring.
The Anti-saturation works by detecting the output. The gain changes depending on the supply voltage, and the attack and release time. The
gain changes constantly as the audio signal increases and/or decreases. The gain step size for the Anti-saturation is 0.4 dB. If the audio signal
has near-constant amplitude, the gain does not change. Table 1 shows the Anti-saturation variable description.
Table 1. PAM8012 Anti-Saturation Variable Description
Varible Description Value
Gain
The pre-set gain of the device when the Anit-saturation is inactive.
The fixed gain is also the initial gain when the device comes out of
shutdown mode or when the Anti-saturation is disabled.
18dB
(Maximum)
Attack Time The minimum time between two gain decrements. 128µS
Release Time The minimum time between two gain increments. 256mS
PL Terminal Function
The voltage value of PL sets the PAM8012 maximum output by an external resistor. Refer to table 2 for anti-saturation and power limit selection.
Table 2. PAM8012 Anti-Saturation and Power Limit Variable Description
R
PL
0 30K < R
PL
< 120K Open
EN
VDD
PL: OFF
Anti-Sat: OFF
PL: ON
Anti-Sat: ON
PL: OFF
Anti-Sat: ON
VDD/2
PL: OFF
Anti-Sat: OFF
PL: ON
Anti-Sat: OFF
PL: ON
Anti-Sat: OFF