TAS5611A

SLAS709 – JUNE 2010

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OSCILLATOR

The oscillator frequency can be trimmed by external control of the FREQ_ADJ pin.

To reduce interference problems while using radio receiver tuned within the AM band, the switching frequency

can be changed from nominal to lower values. These values should be chosen such that the nominal and the

lower value switching frequencies together results in the fewest cases of interference throughout the AM band,

and can be selected by the value of the FREQ_ADJ resistor connected to GND in master mode.

For slave mode operation, turn of the oscillator by pulling the FREQ_ADJ pin to VREG. This will configure the

OSC_I/O pins as inputs and needs to be slaved from an external clock.

PRINTED CIRCUIT BOARD RECOMMENDATION

Use an unbroken ground plane to have good low impedance and inductance return path to the power supply for

power and audio signals. PCB layout, audio performance and EMI are linked closely together. The circuit

contains high fast switching currents; therefore, care must be taken to prevent damaging voltage spikes. Routing

the audio input should be kept short and together with the accompanied audio source ground. A local ground

area underneath the device is important to keep solid to minimize ground bounce.

Netlist for this printed circuit board is generated from the schematic in Figure 12.

Note T1: PVDD decoupling bulk capacitors C60-C64 should be as close as possible to the PVDD and GND_X pins,

the heat sink sets the distance. Wide traces should be routed on the top layer with direct connection to the pins and

without going through vias. No vias or traces should be blocking the current path.

Note T2: Close decoupling of PVDD with low impedance X7R ceramic capacitors is placed under the heat sink and

close to the pins.

Note T3: Heat sink needs to have a good connection to PCB ground.

Note T4: Output filter capacitors must be linear in the applied voltage range preferable metal film types.

Figure 15. Printed Circuit Board - Top Layer

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