11

®

DAC707/708/709

FIGURE 10. Serial Loading of Electrically Isolated DAC708/709.

2.2k

Ω

Carry Out

QA

QB

QC

QD

A

B

C

D

ENT

ENP

Load

No

Connection

+5V

Synchronous Binary Counter

74LS161A

DD

V

Analog

Output

+

+

+

+

2.2µF

0.001µF

1/4 74LS00

CLR

CK

DD

V

DD

V

DD

V

DD

V

TIL117

330

330

DATA STROBE

Serial Input

(16-Bit Data

Stream)

1/6 7407

1/6 7407

1/6 7407

RESET

DATA STROBE

Serial Input

A

2

Analog

Output

Isolation Barrier

V

2.2k

1/4 74LS00

1/4 74LS00

AA A CS

21

0

CLR

WR

DO

Ω

Ω

Ω

330

Ω

2.2k

Ω

2.2k

Ω

+

–

Isolated

Power

Supply

Power

Supply

Voltage

24

3

1

16

15

14

10k

Ω

V

V

DD

DD

DD

In

DAC708

or

DAC709

...

...

V

1

OUT

A

0

A

1

WR

DAC707

V

2

OUT

A

0

A

1

WR

DAC707

Base

Address

Decoder

CS

2

CS

1

16-Bit Data Bus

16-Bit

Address

Bus

D

16

WR

D

0

A

15

A

1

A

0

µP

FIGURE 11. Connecting Multiple DAC707s to a 16-Bit Microprocessor.