Diodes PAM8902 - Manual (Page 8)

PAM8902
Document number: DSxxxxx Rev. 1 - 4
8 of 13
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November 2012
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PAM8902
A Product Line of
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Application Information
Decoupling Capacitor
The PAM8902 is a high-performance CMOS audio amplifier that requires adequate power supply decoupling to ensure the output total harmonic
distortion (THD) as low as possible. The optimum decoupling is achieved by using two different types of capacitors that target on different types
of noise on the power supply leads. For higher frequency transients, spikes, or digital hash on the line, a good low equivalent series-resistance
(ESR) ceramic capacitor, typically 1µF is placed as close as possible to the device AVDD pin for the best operation. For filtering lower frequency
noise signals, a large ceramic capacitor of 10µF or greater placed near the AVDD supply trace is recommended.
External Schottky Diode
Use external schottky diode can get the best driving capability and efficiency.
Since internal power diode has limited driving capability, only in following conditions customer can remove the external schottky diode to reduce
the cost.
1. VSET = GND or Floating and C
L
less than 1µF.
2. The signal frequency less than 4KHz.
3. Haptic application (50-500Hz)
Shutdown Operation
In order to reduce power consumption while not in use, the PAM8902 contains shutdown circuitry amplifier off when a logic low is placed on the
ENA pin. By switching the ENA pin connected to GND, the PAM8902 supply current draw will be minimized in idle mode.
Under-Voltage Lock-Out (UVLO)
The PAM8902 incorporates circuitry designed to detect supply voltage. When the supply voltage drops to 2.2V or below, the PAM8902 goes into
a state of shutdown, and the device comes out of its shutdown state and restore to normal function only when reset the power supply or ENA
pin.
Short-Circuit Protection (SCP)
The PAM8902 has short circuit protection circuitry on the outputs to prevent the device from damage when output-to-output shorted or output-to-
GND shorted occurs. When a short circuit occurs, the device goes into a latch state and must be reset by cycling the voltage on the ENA pin to a
logic low and then 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.
Over-Temperature Protection (OTP)
Thermal protection on the PAM8902 prevents the device from damage when the internal die temperature exceeds +150°C. There is a +15°C
tolerance on this trip point from device to device. Once the die temperature exceeds the set point, the device will enter the shutdown state and
the outputs are disabled in this condition both OUT+ and OUT- will become high impedance. This is not a latched fault. The thermal fault is
cleared once the temperature of the die decreased by +30°C. This large hysteresis will prevent motor boating sound well and the device begins
normal operation at this point with no external system interaction.