Datasheet

AD712
Rev. H | Page 16 of 20
5V
1µs
100
10
0%
90
00823-047
DRIVING A LARGE CAPACITIVE LOAD
The circuit in Figure 46 uses a 100 Ω isolation resistor that enables
the amplifier to drive capacitive loads exceeding 1500 pF; the
resistor effectively isolates the high frequency feedback from
the load and stabilizes the circuit. Low frequency feedback is
returned to the amplifier summing junction via the low-pass filter
formed by the 100 Ω series resistor and the Load Capacitance C
L
.
Figure 47 shows a typical transient response for this connection.
1/2
AD712
0.1µF
0.1µF
–V
IN
+V
IN
INPUT
R
1
2kΩ 1500pF
10kΩ 1500pF
20Ω 1000pF
C1 R1
4.99kΩ
4.99kΩ
30pF
OUTPUT
100Ω
+
–
–
+
TYPICAL CAPACITANCE
LIMIT FOR VARIOUS
LOAD RESISTORS
C
1
UP TO
+
–
00823-046
Figure 47. Transient Response R
L
= 2 kΩ, C
L
= 500 pF
Figure 46. Circuit for Driving a Large Capacitive Load