9

®

DAC701, 702, 703

VOLTAGE OUTPUT MODELS

ANALOG OUTPUT

DAC701 UNIPOLAR

DAC703 BIPOLAR

DIGITAL INPUT CODE

16-BIT

15-BIT

14-BIT

16-BIT

15-BIT

14-BIT

1LSB

(

µV)

153

305

610

305

610

1224

(V)

+9.99985

+9.99969

+9.99939

+9.99960

+9.99939

+9.99878

(V)

0

0

0

–10.0000

–10.0000

–10.0000

ANALOG OUTPUT MODEL

ANALOG OUTPUT

DAC702 BIPOLAR

DIGITAL INPUT CODE

16-BIT

15-BIT

14-BIT

1LSB

(

µA)

0.031

0.061

0.122

(mA)

–0.99997

–0.99994

–0.99988

(mA)

+1.00000

+1.00000

+1.00000

TABLE II. Digital Input and Analog Output Relationships.

If the output cannot be sensed at Common or the system

ground point as mentioned above, the differential output

circuit shown in Figure 8 is recommended. In this circuit the

output voltage is sensed at the load common and not at the

D/A converter common as in the previous circuits. The value

of R

Figure 8 can be reduced to the one shown in Figure 7. Again

The D/A converter and the wiring to its connectors should be

located to provide optimum isolation from sources of RFI

and EMI. The key concept in elimination of RF radiation or

pickup is loop area; therefore, signal leads and their return

conductors should be kept close together. This reduces the

external magnetic field along with any radiation. Also, if a

single lead and its return conductor are wired close together,

they present a small flux-capture cross section for any

external field. This reduces radiation pickup in the circuit.

FIGURE 7. Preferred External Op Amp Configuration.

FIGURE 8. Differential Sensing Output Op Amp

Configuration.

A

1

R

DAC

DAC702

R

B

Common

I

OUT

R

1

‡

R

L

R

3

Sense Output

+5VDC

Supply

±15VDC

Supply

+V

COM

–V

System Ground

Point

+V

COM

Alternate Ground

Sense Connection

R

4

To +V

CC

To –V

CC

To V

DD

1µF

1µF

1µF

*

2.45k

R

F

*

R

2

R should be equal to the output impedance at the current output

to compensate for the bias current drift of A . Use standard 10%,

1/4W carbon composition or equivalent resistors.

B

1

‡

DAC702

Ω

2.45k

10k

Ω

Ω

R

DAC

R

B

R

F

*

R

F

A

1

R

DAC

DAC702

R

6

Common

I

OUT

R

1

R

L

R

3

+5VDC

Supply

±15VDC

Supply

+V

COM

–V

System Ground

Point

+V

COM

Alternate Ground

Sense Connection

R

4

To +V

CC

To –V

CC

To V

DD

1µF

1µF

1µF

2.45k

R

F

*

R

2

DAC702

Ω

10k

Ω

R

DAC

R

F

*

R

F

R

5

R

7

Sense

Output

+

5

R

7

R=

+

F

R

1

R

R

DAC

R