- 3 -

Rev. 0

EVAL-AD7707EB

EVALUATION BOARD INTERFACING

Interfacing to the evaluation board is via either a 9-way d-type connector, SKT1 or a 36-way centronics connector, SKT2.

The pin-out for the SKT1 connector is shown in Fig. 2 and its pin designations are given in Table 2.

The pin-out for the

SKT2 connector is shown in Fig. 3 and its pin designations are given in Table 3.

SKT2 is used to connect the evaluation board to the parallel (printer) port of a PC. Connection is via a standard printer cable.

SKT1 is used to connect the evaluation to any other system. The evaluation board should be powered up before a cable is

connected to either of these connectors.

Fig. 2: Pin Configuration for the 9-Way D-Type Connector, SKT1.

Table 2.:

SKT1 Pin Description

1

1

SCLK

Serial Clock. The signal on this pin is buffered before being applied to the SCLK pin of the AD7707.

2

DRDY

Logic output. This is a buffered version of the signal on the AD7707

DRDY pin

3

CS

Chip Select. The signal on this pin is buffered before being applied to the

CS pin on the AD7707.

4

RESET Reset Input. Data applied to this pin is buffered before being applied to the AD7707 RESET pin.

5

D I N

Serial Data Input. Data applied to this pin is buffered before being applied to the AD7707 DIN pin.

6

DGND

Ground reference point for the digital circuitry. Connects to the DGND plane on the Evaluation board.

7

DOUT

Serial Data Output. This is a buffered version of the signal on the AD7707 DOUT pin.

8DV

DD

Digital Supply Voltage. If no voltage is applied to the board's DV

DD

input terminal then the voltage applied to

this pin will supply the DV

DD

for the digital buffers.

9

N C

Not Connected.

Note

SET-UP CONDITIONS

Care should be taken before applying power and signals to the evaluation board to ensure that all link positions are as per the

required operating mode.

Table 1 shows the position in which all the links are set when the evaluation board is sent out.

Table 1:

Initial Link and Switch Positions

Link No.

Position

Function

LK1

B + B

Both links in position "B" to select the on-board crystal as the master clock for the AD7707.

LK2

A

This selects the AD780 +2.5V output

as the on-board reference.

LK3

A

This connects the REFIN(-) input of the AD7707 to AGND.

LK4

A

The on-board reference provides the reference voltage for the REFIN(+) input of the AD7707.

LK5

I N

The AIN1 pin on the AD7707 is tied to the analog input sockets SKT3.

LK6

I N

The AIN2 pin on the AD7707 is tied to the analog input sockets SKT4.

LK7

I N

The AIN3 pin on the AD7707 is tied to the analog input sockets SKT5.

LK8

A

The LCOM pin on the AD7707 is tied to the AGND.

LK9

A

The HBIAS pin of the AD7707 is tied to the REFIN+ pin.

LK10

A

The HCOM pin on the AD7707 is tied to the AGND.

24

3

1

5

67

8

9