Digital Input Considerations

The threshold of the DAC16’s digital input circuitry is set at

1.4 V, independent of supply voltage. Hence, the digital inputs

can interface with any type of 5 V logic. Illustrated in Figure 5 is

the equivalent circuit of the digital inputs. Note that the indi-

vidual input capacitance is approximately 7 pF.

Q3

Q2

Q1

R2

75k

R1

20k

R3

28k

TO DAC

SWITCH

+5V

+0.7V

–15V

–0.7V

DBX

Figure 5. Equivalent Circuit of a DAC16 Digital Input

This input capacitance can be used in conjunction with an ex-

ternal R-C circuit for digital signal deskewing, if required. In

applications where some of the DAC16’s digital inputs are

not used, the recommended procedure to turn off one or more

inputs is to connect each input line to +5 V as shown in

Figure 6.

DB0

DB1

+5V

DAC16

Figure 6. Handling Unused DAC16 Digital Inputs

Typical Performance Characteristics–DAC16

REV. B

–5–

REFERENCE CURRENT – mA

–2.0

0.2

0.3

0.4

0.5

0.6

0.7

–DNL

+DNL

–1.5

–1.0

–0.5

0

0.5

1.0

1.5

2.0

Figure 8. Differential Nonlinearity

TEMPERATURE – C

–40

–4

–20

0

20406080

–2

0

2

4

+INL

–INL

Figure 11. Integral Nonlinearity

vs. Temperature

TEMPERATURE – C

1.0

–40

0.8

0.6

0.4

0.2

0

–20

0

20406080

Figure 9. Zero Scale Output vs.

Temperature

TEMPERATURE – C

–40

–1.5

–20

0

20406080

–1.0

–0.5

0

0.5

1.5

1.0

+DNL

–DNL

Figure 12. Differential Nonlinearity

vs. Temperature

REFERENCE CURRENT – mA

–4

0.2

–3

–2

–1

0

1

2

3

4

0.3

0.4

0.5

0.6

0.7

–INL

+INL

TEMPERATURE – C

–40

–15

–20

0

20406080

–10

–5

0

5

15

10

Figure 10. Gain Error vs.

Temperature