PCM1791ADB datasheet(35/58 Pages) TI

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PCM1791A

SLES071A − MARCH 2003 − REVISED JANUARY 2004

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Analog Gain of Balanced Amplifier

The DAC voltage outputs are followed by balanced amplifier stages, which sum the differential signals for each

channel, creating a single-ended voltage output. In addition, the balanced amplifiers provide a third-order

low-pass filter function, which band limits the audio output signal. The cutoff frequency and gain are determined

by external R and C component values. In this case, the cutoff frequency is 77 kHz with a gain of 1.83. The

output voltage for each channel is 5.9 Vp-p, or 2.1 V rms.

Application for Monaural-Mode Operation

A single-channel signal from the stereo audio data input is output from both VOUTL and VOUTR as a differential

output. The channel to be output is selected by setting the CHSL bit in register 20. The advantage of monaural

operation is to provide over 115 dB of dynamic range for high-end audio applications.

−

PCM1791A

VOUTR+

VOUTL−

VOUTL+

VOUTR−

L/R Clock

Bit Clock

System Clock

Audio Data

PCM1791A

Controller

Analog

Output

Stage

VOUT

R-Channel

Analog

Output

Stage

VOUT

L-Channel

Analog Output Stage

NOTE: Example R and C values for fC = 77 kHz, R1–R4: 3.6 kΩ, R5, R6: 3.3 kΩ, R7, R8: 680 Ω, C1: 1800 pF, C2, C3: 560 pF.

Figure 37. Connection Diagram for Monaural Mode Interface

PCM1791ADB Datasheet(PDF) 35 Page - Texas Instruments