Figure 5, Applications information – Rainbow Electronics ADC10D020 User Manual

Page 26

Applications Information

(Continued)

The V

CMO

output can be used as the ADC reference source

as long as care is taken to prevent excessive loading of this
pin. However, the V

CMO

output was not designed to be a

precision reference and has more variability than does a
precision reference. Refer to V

CMO

, Common Mode Voltage

Output, in the Electrical Characteristics table. Since the ref-
erence input of the ADC10D020 is buffered, there is virtually
no loading on the V

CMO

output by the V

REF

pin. While the

ADC10D020 will work with a 1.5V reference voltage, it is fully

specified for a 1.0V reference. To use the V

CMO

for a refer-

ence voltage at 1.0V, the 1.5V V

CMO

output needs to be

divided down. The divider resistor values need to be care-
fully chosen to prevent excessive V

CMO

loading. See

Figure

7. While the average temperature coefficient of V

CMO

is 20

ppm/˚C, that temperature coefficient can be broken down to
a typical 50 ppm/˚C between −40˚C and +25˚C and a typical
−12 ppm/˚C between +25˚C and +85˚C.

20025572

FIGURE 5. Improved Low Component Count Reference Biasing

ADC10D020