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SWITCHING FREQUENCY

6.6

R

(8)

POWER SUPPLY DECOUPLING, C

S

MIDRAIL BYPASS CAPACITOR, C

BYP

(9)

DIFFERENTIAL INPUT

SHUTDOWN MODES

TPA2000D2

SLOS291F – MARCH 2000 – REVISED MARCH 2007

(pin 7) and is calculated with the following equation:

The switching frequency was chosen to be centered on 250 kHz. This frequency is the optimum audio fidelity of

oversampling and of maximizing efficiency by minimizing the switching losses of the amplifier. The

recommended values are a resistance of 120 k

Ω and a capacitance of 220 pF. Using these component values,

the amplifier operates properly by using 5% tolerance resistors and 10% tolerance capacitors. The tolerance of

the components can be changed, as long as the switching frequency remains between 200 kHz and 300 kHz.

Within this range, the internal circuitry of the device provides stable operation.

The TPA2000D2 is a high-performance CMOS audio amplifier that requires adequate power supply decoupling

to ensure the output total harmonic distortion (THD) is as low as possible. Power supply decoupling also

prevents oscillations for long lead lengths between the amplifier and the speaker. The optimum decoupling is

achieved by using two capacitors of different types that target 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

filtering lower-frequency noise signals, a larger aluminum electrolytic capacitor of 10 µF or greater placed near

the audio power amplifier is recommended.

function is to reduce noise produced by the power supply caused by coupling into the output drive signal. This

noise is from the midrail generation circuit internal to the amplifier, which appears as degraded PSRR and

THD+N.

for the best THD and noise performance.

Increasing the bypass capacitor reduces clicking and popping noise from power on/off and entering and leaving

The differential input stage of the amplifier cancels any noise that appears on both input lines of a channel. To

use the TPA2000D2 EVM with a differential source, connect the positive lead of the audio source to the RINP

(LINP) input and the negative lead from the audio source to the RINN (LINN) input. To use the TPA2000D2 with

a single-ended source, ac ground the RINN and LINN inputs through a capacitor and apply the audio single to

the RINP and LINP inputs. In a single-ended input application, the RINN and LINN inputs should be

ac-grounded at the audio source instead of at the device inputs for best noise performance.

minimum level during periods of nonuse for battery-power conservation. The SHUTDOWN input terminal should

be held high during normal operation when the amplifier is in use. Pulling SHUTDOWN low causes the outputs

unconnected, because amplifier operation would be unpredictable.

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