PAM8901 / PAM8908

Document number: DS36456 Rev. 2 - 2

10 of 13

www.diodes.com

October 2016

© Diodes Incorporated

PAM8901 / PAM8908

Power Supply Sequencing

Use input coupling capacitors to ensure inaudible turn-on pop. Activate the PAM8901 / PAM8908 after all audio sources have been activated and

their output voltages have settled. On powerdown, deactivate the PAM8901 / PAM8908 before deactivating the audio input source. The EN pin

controls device shutdown: Set to 0.6V or lower to deactivate the PAM8901 / PAM8908; set to 1.4V or higher to activate.

TrueCapFree Headphone Amplifiers

The TrueCapFree amplifier architecture operates from a single supply voltage and uses two internal charge pumps to generate a positive supply

and a rail for the headphone amplifier. The output voltages are centered around 0V and are capable of positive and negative voltage swings as

shown in the following drawing.

TrueCapFree amplifiers require no output DC-blocking capacitors. The headphone connector shield pin connects to ground and will interface with

headphones and non-headphone accessories. The PAM8901 / PAM8908 is a TrueCapFree amplifier.

LAYOUT RECOMMENDATIONS

Exposed Pad on PAM8901 / PAM8908

Solder the exposed metal pad on the PAM8901 / PAM8908 U-QFN3030-16 (Type US) package to the landing pad on the PCB. Connect the

landing pad to ground or leave it electrically unconnected (floating). Do not connect the landing pad to PVDD or to any other power supply voltage.

If the pad is grounded, it must be connected to the same ground as the PGND. Soldering the thermal pad is required for mechanical reliability and

enhances thermal conductivity of the package.

GND Connections

The SGND pin is an input reference and must be connected to the headphone ground connector pin. This ensures no turn-on pop and minimizes

output offset voltage. Do not connect more than ±0.3V to SGND.

PGND is a power ground. Connect supply decoupling capacitors for PVDD, HPVDD, and HPVSS to PGND.

Power Supply Connections

Connect the supply voltage to the PVDD pin and decouple it with an X5R or better capacitor. Place both PVDD capacitors within 5mm of PVDD

pin on the PAM8901 / PAM8908. Ensure that the ground connection of PVDD capacitor has a minimum length return path to the device. Failure to

properly decouple the PAM8901 / PAM8908 may degrade audio or EMC performance.