Datasheet

AD569
REV. A
–9–
Figure 13. Low-Cost ± 5 V Tracking Reference
a. Bandwidth
b. Phase Shift
Figure 14. Full Power Multiplying Performance
a. Time Domain
b. Frequency Domain
Figure 15. Multiplying Mode Performance (Input Code
0001
H
)
MULTIPLYING PERFORMANCE
Figure 14 illustrates the gain and phase characteristics of the
AD569 when operated in the multiplying mode. Full-power
bandwidth is shown in Figure 14a and the corresponding phase
shift is shown in Figure 14b. Performance is plotted for both a
full-scale input of FFFF
H
and an input of 8080
H
. An input rep-
resents worst-case conditions because it places the buffer taps at
the midpoints of both dividers. Figure 15 illustrates the
AD569’s ability to resolve 16-bits (where 1 LSB is 96 dB below
full scale) while keeping the noise floor below –130 dB with an
ac reference of 1 V rms at 200 Hz.
Multiplying feedthrough is due to capacitive coupling between
the reference inputs and the output. As shown in Figure 16,