PAM8012

Document number: DSxxxxx Rev. 1 - 3

9 of 14

www.diodes.com

October 2012

© Diodes Incorporated

PAM8012

A Product Line of

Diodes Incorporated

Over Temperature Protection (OTP)

Thermal protection on the PAM8012 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. This is not a latched fault. The thermal fault is cleared once the temperature of the die decreased by +40°C. This large

hysteresis will prevent motor boating sound well and the device begins normal operation at this point with no external system interaction.

POP and Click Circuitry

The PAM8012 contains circuitry to minimize turnon and turn-off transients or “click and pops”, where turn-on refers to either power supply turn-

on or device recover from shutdown mode. When the device is turned on, the amplifiers are internally muted. An internal current source ramps

reference voltage is stable the device will begin full operation. For the best power-off pop performance, the amplifier should be set in shutdown

mode prior to removing the power supply voltage.

PCB Layout Guidelines

Grounding

It is recommended to use plane grounding. Noise currents in the output power stage need to be returned to output noise ground and nowhere

else. When these currents circulate elsewhere, they may get into the power supply, or the signal ground, etc, even worse, they may form a loop

and radiate noise. Any of these instances results in degraded amplifier performance. The output noise ground that the logical returns for the

output noise currents with Class-D switching must tie to system ground at the power exclusively. Signal currents for the inputs, reference need

to be returned to quite ground. This ground only ties to the signal components and the GND pin. GND then ties to system ground.

Power Supply Line

It is recommended that all the trace could be routed as short and thick as possible. For the power line layout, just imagine water stream, any

barricade placed in the trace (shown in Figure 2) could result in the bad performance of the amplifier.

Figure 2: Power Line

Components Placement

Decoupling capacitors as previously described, the high-frequency 1µF decoupling capacitors should be placed as close to the power supply

terminal.

Input resistors and capacitors need to be placed very close to input pins.

Output filter - The ferrite EMI filter should be placed as close to the output terminals as possible for the best EMI performance, and the

capacitors used in the filters should be grounded to system ground.