ADC12D040 datasheet(21/22 Pages) NSC

21 / 22 page

Applications Information (Continued)

improve performance. The LMH6702 and the LMH6628

have been successfully used to drive the analog inputs of the

ADC12D040.

Also, it is important that the signals at the two inputs have

exactly the same amplitude and be exactly 180o out of phase

with each other. Board layout, especially equality of the

length of the two traces to the input pins, will affect the

effective phase between these two signals. Remember that

an operational amplifier operated in the non-inverting con-

figuration will exhibit more time delay than will the same

device operating in the inverting configuration.

Operating with the reference pins outside of the speci-

fied range. As mentioned in Section 1.2, V

REF should be in

the range of

1.0V

≤ V

REF

≤ 2.4V

Operating outside of these limits could lead to performance

degradation.

Using a clock source with excessive jitter, using exces-

sively long clock signal trace, or having other signals

coupled to the clock signal trace. This will cause the

sampling interval to vary, causing excessive output noise

and a reduction in SNR and SINAD performance.

ADC12D040 Datasheet(PDF) 21 Page - National Semiconductor (TI)