Figure 7. Active Low Pass Filter with Digitally Selected Break Frequency
f
C1
f
C2
TTL
Control
150 pF
1500 pF
+ 15 V
DG21 1B
GND
30 pF
LM101A
+ 15 V
- 15 V
Frequency - Hz
1101001K10K100K1M
- 40
0
160
120
80
V oltage Gain - dB
f
C4
Select
f
C3
Select
f
C2
Select
f
C1
Select
R
1
= 10 kΩ
R
2
= 10 kΩ
R
3
= 1 MΩ
V
OUT
V
1
V-
C
4
C
3
C
2
C
1
f
C4
0.015 µF
0.15 µF
- 15 V
-
+
f
C3
40
A
L
(Voltage Gain Below Break Frequency) =
= 100 (40 dB)
R
3
R
1
f
C
(Break Frequency) =
1
2πR
3
C
X
1
2πR
1
C
X
f
L
(Unity Gain Frequency) =
Max. Attenuation =
R
DS(on)
10 kΩ
≈
- 47 dB
f
L1
f
L2
f
L3
f
L4
www.vishay.com
8
Document Number: 70040
S11-0179-Rev. J, 07-Feb-11
Vishay Siliconix
DG211B, DG212B
APPLICATIONS
Vishay Siliconix maintains worldwide manufacturing capability. Products may be manufactured at one of several qualified locations. Reliability data for Silicon
Technology and Package Reliability represent a composite of all qualified locations. For related documents such as package/tape drawings, part marking, and
reliability data, see www.vishay.com/ppg?70040
.
Figure 8. A Precision Amplifier with Digitally Programable Input and Gains
