6

output. Matched switching times and fast switching will

reduce glitches considerably. (Measured as one half the

Product of duration and amplitude.)

Decoupling and Grounding

For best accuracy and high frequency performance, the

grounding and decoupling scheme shown in Figure 1 should

be used. Decoupling capacitors should be connected close

to the HI-DAC80V (preferably to the device pins) and should

be tantalum or electrolytic bypassed with ceramic types for

best high frequency noise rejection.

Reference Supply

An internal 6.3V reference is provided on board the

HI-DAC80V. The voltage (pin 24) is accurate to

±0.8% and

must be connected to the reference input (pin 16) for

specified operation. This reference may be used externally,

provided current drain is limited to 2.5mA. An external buffer

amplifier is recommended if this reference is to be used to

drive other system components. Otherwise, variations in the

load driven by the reference will result in gain variations of

the HI-DAC80V. All gain adjustments should be made under

constant load conditions.

Output Voltage Ranges

18

19

20

15

-

+

0.01

µF

1

µF

14

21

22

0.01

µF

1

µF

24

16

FIGURE 1.

TABLE 2. RANGE CONNECTIONS

RANGE

CONNECT

PIN 15

PIN 17

PIN 19

Unipolar

0 to +5V

18

NC

20

0 to +10V

18

NC

NC

Bipolar

±2.5V

18

20

20

±5V

18

20

NC

±10V

19

20

15

TABLE 3. GAIN AND OFFSET CALIBRATIONS

UNIPOLAR CALIBRATION

Step 1:

Offset

Turn all bits OFF (11 . . . 1)

Adjust R2 for 0V out

Step 2:

Gain

Turn all bits ON (00 . . . 0)

Adjust R1 for FS - 1 LSB

That is:

4.9988 for 0 to +5V range

9.9976 for 0 to +10V range

BIPOLAR CALIBRATION

Step 1:

Offset

Turn all bits OFF (11 . . . 1)

Adjust R2 for Negative FS

That is:

-10V for

±10V range

-5V for

±5V range

-2.5V for

±2.5V range

Step 2:

Gain

Turn all bits ON (00 . . . 0)

Adjust R1 for Positive FS - 1 LSB

That is:

+9.9951V for

±10V Range

+4.9976V for

±5V Range

+2.4988V for

±2.5V Range

This Bipolar procedure adjusts the output range end points. The

maximum error at zero (half scale) will not exceed the Linearity

Error. See the “Accuracy” Specifications.

18

19

20

15

-

+

6.3K

21

-

+

CONTROL

AMP

3.9

M

Ω

R2

12.6k

Ω

R1

2.8M

Ω

0.01

µF

10k

Ω TO

100k

Ω

24

17

16

23

5k

Ω

5k

Ω

5k

Ω

TO

100k

Ω

FIGURE 2. HI-DAC80V

HI-DAC80V