9

®

DAC715

R

you may wish to connect DCOM to SYSTEM GROUND as

well.

GAIN AND OFFSET ADJUST

Connections Using Potentiometers

GAIN and OFFSET adjust pins provide for trim using

external potentiometers. 15-turn potentiometers provide suf-

ficient resolution. Range of adjustment of these trims is at

least

±0.3% of Full Scale Range. Refer to Figure 6.

Using D/A Converters

The GAIN ADJUST and OFFSET ADJUST circuits of

the DAC715 have been arranged so that these points may

be easily driven by external D/A converters. Refer to

Figure 7. 12-bit D/A converters provide an OFFSET adjust

resolution and a GAIN adjust resolution of 30

µV to 50µV

per LSB step.

Nominal values of GAIN and OFFSET occur when the D/A

converters outputs are at approximately half scale, 0V.

DIGITAL INTERFACE

BUS INTERFACE

The DAC715 has a 16-bit double-buffered data interface

with control lines for easy connection to a 16-bit bus. The

double-buffered feature permits update of several D/As

simultaneously.

A

is the enable for the D/A LATCH. WR is used to strobe data

into latches enabled by A

diagram of Figure 1 and to Timing Diagram on page 3.

CLR sets the INPUT DATA LATCH and D/A LATCH to

0000

SINGLE-BUFFERED OPERATION

FIGURE 5. System Ground Considerations for High-Resolution D/A Converters.

R

1

Sense

Output

R

L

R

2

R

3

Alternate Ground

Sense Connection

System Ground

ACOM

DCOM

Bus

Interface

DAC715

Analog

Power

Supply

0.01µF

(1)

0.01µF

To +V

CC

To –V

CC

NOTE: (1) Locate close to DAC715 package.

V

OUT

5k

Ω

10k

Ω

V

REF