LT1995 Linear Technology, LT1995 Datasheet - Page 15

• Manufacturer Part Number: LT1995
• Description: 32MHz - 1000V/us Gain Selectable Amplifier
• Manufacturer: Linear Technology

APPLICATIO S I FOR ATIO
AC-Coupling Methods for Single Supply Operation
The LT1995 can be used in many single-supply applications
using AC-coupling without additional biasing circuitry.
AC-coupling the LT1995 in a difference amplifier configu-
ration (as in Figure 1) is a simple matter of adding coupling
capacitors to each input and the output as shown in the
example of Figure 5. The input voltage V
REF pin establishes the quiescent voltage on the input and
output pins. The V
impedance to avoid degrading the CMRR (0.5Ω for
1dB CMRR change typically).
V
V
V
IN
IN
IN
*
*
*
10
10
10
8
9
1
2
3
8
9
1
2
3
8
9
1
2
3
BIAS
U
*CONFIGURE M INPUTS FOR DESIRED G PARAMETER; REFER TO FIGURE 2 FOR CONNECTIONS
M4
M2
M1
P1
P2
P4
M4
M2
M1
P1
P2
P4
M4
M2
M1
P1
P2
P4
LT1995
LT1995
LT1995
signal should have a low source
A = 0.875
A = 0.800
A = 0.667
–V
–V
–V
U
4
4
4
+V
+V
+V
Figure 3. Noninverting Amplifier Input Attenuation Configurations (A > 0.5)
7
7
7
REF
REF
REF
5
5
5
W
6
6
6
V
V
V
OUT
OUT
OUT
BIAS
V
IN
applied to the
V
V
IN
IN
*
*
*
U
10
10
10
8
9
1
2
3
8
9
1
2
3
8
9
1
2
3
M4
M2
M1
P1
P2
P4
M4
M2
M1
P1
P2
P4
M4
M2
M1
P1
P2
P4
LT1995
LT1995
LT1995
A = 0.857
A = 0.750
A = 0.625
–V
–V
–V
4
4
4
+V
+V
+V
7
7
7
REF
REF
REF
5
5
5
6
6
6
Figure 4. Unique Noninverting Gain Configurations
V
V
V
OUT
OUT
OUT
8
7
5
3
1
6
4
2
1
V
V
V
IN
IN
IN
*
*
*
10
10
10
GAIN COMBINATION
8
9
1
2
3
8
9
1
2
3
8
9
1
2
3
M4
M2
M1
P1
P2
P4
M4
M2
M1
P1
P2
P4
M4
M2
M1
P1
P2
P4
LT1995
LT1995
LT1995
A = 0.833
A = 0.714
A = 0.571
–V
–V
–V
4
4
4
+V
+V
+V
7
7
7
REF
REF
REF
www.DataSheet4U.com
5
5
5
6
6
6
1995 F04
1995 F03
V
V
V
73
OUT
OUT
OUT
LT1995
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