PCM1737 datasheet(24/32 Pages) TI2

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PCM1737

APPLICATIONS INFORMATION

CONNECTION DIAGRAMS

A basic connection diagram is shown in Figure 13, with the

necessary power supply bypassing and decoupling compo-

nents. Burr-Brown recommends using the component values

shown in Figure 13 for all designs.

The use of series resistors (22

Ω to 100Ω) are recommended

for SCLK, LRCK, BCLK, DATA inputs. The series resistor

combines with the stray PCB and device input capacitance

to form a low-pass filter which reduces high frequency noise

emissions and helps to dampen glitches and ringing present

on clock and data lines.

POWER SUPPLIES AND GROUNDING

The PCM1737 requires a +5V analog supply and a +3.3V

digital supply. The +5V supply is used to power the DAC

analog and output filter circuitry, while the +3.3V supply is

used to power the digital filter and serial interface circuitry.

For best performance, the +3.3V supply should be derived

from the +5V supply using a linear regulator, as shown in

Figure 13. Burr-Brown’s REG1117-3.3 is an ideal choice for

this application.

Proper power supply bypassing is shown in Figure 13. The

bypass capacitors should be tantalum or aluminum electro-

lytic, while the 0.1

µF capacitors are ceramic (X7R type is

recommended for surface-mount applications).

D/A OUTPUT FILTER CIRCUITS

Delta-sigma D/A converters utilize noise-shaping techniques

to improve in-band Signal-to-Noise Ratio (SNR) perfor-

mance at the expense of generating increased out-of-band

noise above the Nyquist Frequency, or fS/2. The out-of-

band noise must be low-pass filtered in order to provide the

optimal converter performance. This is accomplished by a

combination of on-chip and external low-pass filtering.

Figures 12a and 14 show the recommended external low-

pass active filter circuits for dual and single-supply applica-

tions. These circuits are 2nd-order Butterworth filters using

the Multiple Feedback (MFB) circuit arrangement, which

reduces sensitivity to passive component variations over

frequency and temperature. For more information regarding

MFB active filter design, please refer to Burr-Brown Appli-

cations Bulletin AB-034.

FIGURE 14. Dual-Supply Filter Circuit.

FIGURE 13. Basic Connection Diagram.

LRCK

DATA

BCLK

CLKO

SCLK

TEST1

TEST2

CCR

GNDR

COMR

OUTR

GNDA

MDI

MDO

ZEROR

ZEROL

RSTB

CCL

GNDL

COML

OUTL

CCA

From/To

Audio

Source

+3.3V

Regulator

Analog

Ground

(1)

To/From

Host

Controller

Zero Flag

Outputs

From Host or

Master Reset

Output

Filter

Circuits

+5V Analog

1, C4, C6, C9 = 10µF Tantalum or Aluminum Electrolytic

2, C5 = 0.1µF Ceramic

3, C10 = 1µF Tantalum or Aluminum Electrolytic

7, C8 = 1-10µF Aluminum Electrolytic

NOTE: (1) R

S = 20Ω to 100Ω

PCM1737

OUT

OPA2134

V ≈ –

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