Datasheet
LTC6406
12
6406fc
APPLICATIONS INFORMATION
Figure 1. DC Test Circuit
–
+
1
SHDN
5 6
–IN
7
+OUT
8
+OUTF
16 15
+IN
V
TIP
NC
14
–OUT
100k
13
–OUTF
V
–OUTF
R
F
C
F
V
+OUTF
V
–OUT
V
+OUT
2
V
+
3
V
–
V
+
V
+
V
–
V
+
V
–
4
V
OCM
V
SHDN
V
VOCM
V
OCM
12
V
–
V
–
11
V
+
10
V
+
9
V
–
V
–
V
–
V
–
C
F
V
–
V
–
6406 F01
LTC6406
SHDN
0.1μF
0.01μF
V
CM
R
F
R
I
R
I
R
BAL
100k
R
BAL
100k
+
–
V
INP
–
+
V
INM
V
–IN
V
+IN
V
OUTCM
V
+
0.1μF
0.1μF
0.1μF
0.1μF
1.25pF
1.25pF
1.25pF
0.1μF
0.01μF
50Ω
50Ω
Functional Description
The LTC6406 is a small outline, wideband, low noise, and
low distortion fully-differential amplifi er with accurate
output phase balancing. The LTC6406 is optimized to
drive low voltage, single-supply, differential input analog-
to-digital converters (ADCs). The LTC6406 input common
mode range is rail-to-rail, while the output common mode
voltage is independently adjustable by applying a voltage
on the V
OCM
pin. The output voltage swing extends from
near ground to 2V, to be compatible with a wide range of
ADC converter input requirements. This makes the LTC6406
ideal for level-shifting signals with a wide common mode
range for driving 12-bit to 16-bit single supply, differential
input ADCs. The differential output allows for twice the
signal swing in low voltage systems when compared to
single-ended output amplifi ers. The balanced differential
nature of the amplifi er also provides even-order harmonic
distortion cancellation, and less susceptibility to common
mode noise (like power supply noise). The LTC6406 can be
used as a single-ended input to differential output amplifi er,
or as a differential input to differential output amplifi er.
The LTC6406 output common mode voltage, defi ned as the
average of the two output voltages, is independent of the
input common mode voltage, and is adjusted by applying
a voltage on the V
OCM
pin. If the pin is left open, there
is an internal resistive voltage divider, which develops a
potential of 1.25V (if the supply is 3V). It is recommended
that a high quality ceramic capacitor is used to bypass the
V
OCM
pin to a low impedance ground plane. The LTC6406’s
internal common mode feedback path forces accurate