PCM1740ESLASH2K datasheet(17/26 Pages) TI2

17 / 26 page

PCM1740

SBAS128B

www.ti.com

FIGURE 16. Basic Connection Diagram.

XT1

PGND

XTUN

MCKO

AD0

AD1

SCL

SDA

RST

OUTR

AGND

XT2

DGND

SCKO

RSV

LRCK

DATA

BCK

ZERO

COM

OUTL

I2C BUS

and Reset

Control

from

µP

VCXO

Control

Voltage

(0V to +3V)

27MHz

Master Clock

Low Pass

Filter (2)

Right Channel

Output

From Audio

Decoder

Serial

Interface

256/384f

to AudioDecoder

and Data Converters

Buffer(1)

10k

Ω

Zero Flag

NOTES: (1) Use buffer when driving multiple nodes.

(2) See applications information section for filter

recommendations.

PCM1740

27MHz Crystal

1 to C6 = 1µF to 10µF Capacitors

( Aluminum Electrolytic or tantalum)

Low Pass

Filter (2)

Left Channel

Output

Analog

Ground

+5V

APPLICATIONS INFORMATION

BASIC CONNECTION DIAGRAM

A basic connection diagram is shown in Figure 16. Power

supply and reference decoupling capacitors should be located

as close as possible to the PCM1740 package. The 27MHz

crystal should also be located as close as possible to the

package, to reduce the effects of parasitic capacitance on

VCXO operation.

A single +5V supply is recommended, to avoid issues with

power-supply sequencing and SCR latch-up. It is recom-

mended that this supply be separate from the system digital

power supply. In cases where this is not practical, an

Audio

Serial

I/F

I2C

I/F

and

REGs

VCXO

AD1

AD0

SCL

SDA

XTUN

XTI

XTO

RST

27MHz

Crystal

Interpolation

Filter

and

Programmable

Functions

DAC

(R)

Counter N

OUTL

COM

ZERO

SCKO

MCKO

To Audio Decoder

and Data Converters

To Other Devices

OUTR

Counter M

Power Supply

Reset

BCIN

LRCIN

DIN

AGND

DGND

PGND

DAC

(L)

Low-Pass

Filter

and Output

Amp

Audio

Decoder

MPEG

System Controller

27MHz Reference

Generated by

Receive Counter

Line-Out_L

Line-Out_R

LPF

VCO

Low-Pass

Filter

and

Analog

Mute

LPF

VCXO Control Voltage

Phase

Detec.

FIGURE 17. Typical Application Diagram.

inductor or ferrite bead should be placed in series with the

+5V supply connection to reduce or eliminate high-fre-

quency noise on the supply line.

In cases where overshoot or ringing is present on the LRCK

or BCK signals, a series resistance of 25

Ω to 100Ω should

be added. The resistor forms a simple RC filter with the

device input and printed circuit board (PCB) parasitic ca-

pacitance, dampening the overshoot and ringing effects,

while reducing high-frequency noise emissions.

TYPICAL APPLICATION DIAGRAM

Figure 17 shows the PCM1740 being used as part of the

audio sub-system in a set-top box application.

PCM1740E/2K Datasheet(PDF) 17 Page - Texas Instruments

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