Datasheet
DC-COUPLED SINGLE-TO-DIFFERENTIAL
402W
250W
402W
1/4
OPA4830
+5V
-5V
V
CM
1.5V
1/4
OPA4830
1/4
OPA4830
50W750W750W402W
1/4
OPA4830
+V =V +V (1+)
OUT CM I
402W
R
G
-V =V - V (1+)
OUT CM I
402W
R
G
750W
750W
0.1 Fm
R
I
200W
R
G
V
CM
2
V
I
200W
OPA4830
www.ti.com
.................................................................................................................................................... SBOS350A – DECEMBER 2006 – REVISED MAY 2008
common-mode voltage, V
CM
, is cut in half and applied
CONVERSION to the noninverting input of the second stage. The
signal path in this stage sees a gain of – 1V/V while
The previous differential output circuits were set up to
this (1/2 × V
CM
) voltage sees a gain of +2V/V. The
receive a differential input as well as provide a
output of this second stage is then the original
differential output. Figure 82 illustrates one way to
common-mode voltage plus the inverted signal from
provide a single-to-differential conversion, with dc
the output of the first stage. The 2nd stage output
coupling, and independent output common-mode
appears directly at the output of the noninverting final
control using a quad op amp.
stage. The inverting node of the inverting output
stage is also biased to the common-mode voltage,
The circuit of Figure 82 provides several useful
equal to the common-mode voltage appearing at the
features for isolating the input signal from the final
output of the second stage, creating no current flow
outputs. Using the first amplifier as a simple
and placing the desired V
CM
at the output of this
noninverting stage gives an independent adjustment
stage as well.
on R
I
(to set the source loading) while the gain can
be easily adjusting in this stage using the R
G
resistor.
The next stage allows a separate output
common-mode level to be set up. The desired output
Figure 82. Wideband, DC-Coupled, Single-to-Differential Conversion
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