Linear Technology DC961B Demo Manual page 4

DEMO MANUAL DC961B
Quick test proceDure
C. Driving the Analog Inputs of an ADC
Figure 5 shows the DC961 output components when driv-
ing an ADC. Optimum values for the DC961 output com-
ponents when driving an LTC2202/LTC2203 or LTC2245/
LTC2246 ADC.
R12, 49.9
LT1994
–
OUT
C21
10pF
R15, 49.9
LT1994
+
OUT
Figure 5. DC961 Output Component Values
4
DC961
J3
TO DIFFERENTIAL
– INPUT OF AN
C18
V
OUT
LTC2202/LTC2203
10pF
OR
J4
LTC2245/LTC2246
ADC
+
C22
V
OUT
10pF
dc961b F05
D. Using a DC961 to Implement a Fully Differential,
Second Order Lowpass Filter.
R1, 0
+
V
IN
C8, 1µF
J1
R2 Z1
0
R10, 0
–
V
IN
C12, 1µF
J2
R6
Z2
0
Figure 6. A DC961 Configured as a Second Order
Lowpass Filter
R21
R31
R11
C11
R12
R32
R22
Figure 7. Fully Differential, 2nd Order, Lowpass Filter
Design Schematic
DC961
R3
C5
R9
+
V
0.1µF
3
8
R12, 50
–
5
+
7
C11 V LT1994
2
OCM
R15, 50
–
1
+
4
6
0.1µF
C6
R8
R7
dc961b F06
C21
+
V
0.1µF
3
8
–
5
+
2
LT1994
0.1µF –
1
+
4
6
7
C22
dc961b F07
J3
–
V
OUT
J4
+
V
OUT
dc961bf