LT6600CS8-15-PBF LINER [Linear Technology], LT6600CS8-15-PBF Datasheet - Page 7

• Manufacturer Part Number: LT6600CS8-15-PBF
• Description: Very Low Noise, Differential Amplifi er and 15MHz Lowpass Filter
• Manufacturer: LINER [Linear Technology]

APPLICATIONS INFORMATION
Interfacing to the LT6600-15
The LT6600-15 requires two equal external resistors, R
to set the differential gain to 536Ω/R
fi lter are the voltages V
external components, Figure 1. The difference between
V
age of V
Similarly, the voltages V
and 5 of the LT6600-15 are the fi lter outputs. The differ-
ence between V
voltage. The average of V
mode output voltage.
Figure 1 illustrates the LT6600-15 operating with a single
3.3V supply and unity passband gain; the input signal is
DC coupled. The common mode input voltage is 0.5V, and
the differential input voltage is 2V
IN
+
and V
IN
+
IN
and V
–
–1
is the differential input voltage. The aver-
2
1
0
3
2
1
0
OUT
3
2
1
0
IN
V
V
V
–
500mV
+
V
V
is the common mode input voltage.
and V
IN
IN
+
–
OUT
P-P
IN
OUT
+
(DIFF)
V
+
OUT
IN
V
and V
V
and V
IN
+
+
IN
+
–
and V
–
is the differential output
P-P
OUT
IN
t
–
. The common mode
t
OUT
IN
t
–
presented to these
appearing at Pins 4
. The inputs to the
V
V
–
V
V
V
IN
IN
IN
IN
IN
is the common
–
+
–
+
+
0.1μF
0.1μF
536Ω
536Ω
133Ω
62pF
133Ω
62pF
0.01μF
536Ω
536Ω
0.01μF
0.01μF
IN
+
–
Figure 1
Figure 2
Figure 3
1
7
2
8
,
1
7
2
8
2V
LT6600-15
+
–
–
LT6600-15
+
3
6
3.3V
1
7
2
8
3
6
5V
output voltage is 1.65V, and the differential output voltage
is 2V
output voltage is determined by the voltage at Pin 2. Since
Pin 2 is shorted to Pin 7, the output common mode is the
mid-supply voltage. In addition, the common mode input
voltage can be equal to the mid-supply voltage of Pin 7
(see the Distortion vs Input Common Mode Level graphs
in the Typical Performance Characteristics section).
Figure 2 shows how to AC couple signals into the
LT6600-15. In this instance, the input is a single-ended
signal. AC coupling allows the processing of single-ended
or differential signals with arbitrary common mode levels.
The 0.1μF coupling capacitor and the 536Ω gain setting
resistor form a high pass fi lter, attenuating signals below
3kHz. Larger values of coupling capacitors will proportion-
ally reduce this highpass 3dB frequency.
+
–
–
LT6600-15
+
0.1μF
+
–
0.1μF
4
3.3V
3
5
6
4
5
+
–
P-P
0.1μF
4
5
for frequencies below 15MHz. The common mode
V
V
OUT
OUT
V
V
OUT
OUT
+
–
V
V
+
–
OUT
OUT
+
–
3
2
1
0
3
2
1
0
V
3
2
1
0
V
V
V
V
V
V
OUT
OUT
OUT
OUT
V
V
+
–
OUT
OUT
+
–
660015 F01
660015 F03
+
–
LT6600-15
660015 F02
t
t
660015fa
7