Datasheet

Data Sheet ADA4433-1
Rev. 0 | Page 13 of 16
CONFIGURING THE ADA4433-1 FOR SINGLE-
ENDED INPUT SIGNALS
The ADA4433-1 is a fully differential filter/driver that can be
used as a single-ended-to-differential amplifier or as a differential-
to-differential amplifier. In single-ended-to-differential output
applications, bias the −IN input appropriately to optimize the
output range. To make the most efficient use of the output range
of the ADA4433-1, especially with low supply voltages, it is
important to allow the differential output voltage to swing in
both a positive and negative direction around the output common-
mode voltage (V
OCM
) level, the midsupply point. To do this, the
differential input voltage must swing both positive and negative.
Figure 23 shows a 1 V p-p single-ended signal on +IN with −IN
grounded. This produces a differential input voltage that ranges
from 0 V to 1 V. The resulting differential output voltage is
strictly positive, where each output swings only above V
+OUT
or
below V
−OUT
, the midsupply V
OCM
level. Directly at the output of the
ADA4433-1, the output voltage extends from 0.65 V to 2.65 V,
requiring a full 2 V of output to produce a 1 V p-p signal at the
receiver (represented by the voltage across 2R).
To make a more efficient use of the output range, the −IN input is
biased at the midpoint of the expected input signal range, as shown
in Figure 24. A 1 V p-p single-ended signal on +IN, with −IN
biased at 0.5 V, produces a differential input voltage that ranges
from −0.5 V to +0.5 V. The resulting differential output voltage
now contains both positive and negative components, where
each output swings both above and below the midsupply V
OCM
level. Directly at the output of the ADA4433-1, the output
voltage now extends only from 1.15 V to 2.15 V, requiring only
1 V of the output to produce a 1 V p-p signal at the receiver.
Figure 23. Single-Ended-to-Differential Configuration with Negative Input (−IN) Connected to Ground
Figure 24. Single-Ended-to-Differential Configuration with Negative Input (−IN) Connected to 0.5 V
INPUT SIGNAL
ADA4433-1
V
+IN
V
OCM
=
1.65V
V
+OUT
V
–OUT
+
–
V
–IN
V
DIFF
(IN) = V
+IN
– V
–IN
V
DIFF
(OUT) = V
+OUT
– V
–OUT
V
OUT
= V
DIFF
(OUT) ÷ 2
V
OUT
R
2R
2.65V
0.65V
R
0V
1.0V
1V p-p
DIFFERENTIAL OUTPUT SIGNAL DIFFERENTIAL OUTPUT SIGNAL ACROSS 2R
1V p-p
10597-028
INPUT SIGNAL
ADA4433-1
V
OCM
=
1.65V
+
–
V
DIFF
(IN) = V
+IN
– V
–IN
V
DIFF
(OUT) = V
+OUT
– V
–OUT
V
OUT
= V
DIFF
(OUT) ÷ 2
V
OUT
R
2R
1.15V
2.15V
R
0V
0.5V
1.0V
1V p-p
DIFFERENTIAL OUTPUT SIGNAL DIFFERENTIAL OUTPUT SIGNAL ACROSS 2R
1V p-p
10597-029
V
+IN
V
+OUT
V
–OUT
V
–IN