2

®

DEM-PCM3500

FIGURE 1. Schematic.

CONNECTORS

CN1 is the power supply connector for the DEM-PCM3500.

GND pin should be connected to the negative (–) or ground

terminal of the power supply or battery, and functions as the

analog ground connection.

CN2 is the host interface connector. It includes connections for

the serial interface and system clock input /output. The connec-

tor pins correspond directly to the pin names of the PCM3500.

Refer to the PCM3500 data sheet for more details regarding the

operation and requirements for these connections.

to the PCM3500 analog-to-digital converter input, while the

GND pin is connected to analog ground. The full-scale input

power supply.

nected to the PCM3500 digital-to-analog converter output,

while the GND pin is connected to analog ground. The full-

or 1.8Vp-p for a +3V power supply.

DIP SWITCH SETTINGS

Table I shows the function of each switch setting for SW1.

Each switch corresponds directly to a pin of the PCM3500.

Refer to the PCM3500 data sheet for more details regarding

the operation and requirements for these pin functions.

TABLE I. DIP Switch Settings.

SW1

DESCRIPTION

PWDN

H = Power Down Disabled (normal operation)

L = Power Down Enabled

LOOP

H = ADC-to-DAC Loop Back Enabled

L = ADC-to-DAC Loop Back Disabled

HPFD

H = ADC High Pass Filter Disabled

L = ADC High Pass Filter Enabled

T/S

H = Time Slot Mode Enabled

L = Time Slot Mode Disabled

M/S

H = Master Mode Enabled

L = Slave Mode Enabled

CRYSTAL OSCILLATOR OPERATION

The PCM3500 contains an internal crystal oscillator circuit.

(512 times the desired sample frequency). The crystal value

should be set in the range from 10pF – 33pF, with 22pF

being the typical value. When using the crystal oscillator,

BCK and FS should be derived from SCKIO when using

Slave mode. Alternatively, the PCM3500 may be set to

Master mode so that the BCK and FS are generated by the

CODEC itself.

V

COM

V

V

V

IN

AGND

M/S

TSC

BCK

FS

DIN

DOUT

FSO

V

CC

AGND

V

OUT

AGND

PDWN

LOOP

HPFD

XTI

XTO

SCKIO

DGND

V

DD

1

2

3

4

5

6

7

8

9

10

11

12

24

23

22

21

20

19

18

17

16

15

14

13

U1

PCM3500

PWDN

SW1

DSS105

LOOP

HPFD

DOUT

FSO

FS

DIN

BCK

SCKO

GND

XTI

CN2

VH8

V

OUT

GND

CN4

VH2

C

1

1

µF

C

2

2.2

µF

+

C

3

4.7

µF

+

C

4

4.7

µF

+

+

SCKIO

XTI

C

6

0.1

µF

C

7

4.7

µF

+

C

11

1

µF

+

V

IN

GND

CN3

VH2

GND

V

CC

CN1

VH2

PDWN

LOOP

HPFD

SCKIO

+ C

8

4.7

µF

C

5

0.1

µF

+

C

10

0.1

µF

C

9

100

µF

C

S

C

S

XTAL

OPTIONAL

XTI