TLE2682 Datasheet, PDF (33/49 Pages) Texas Instruments – HIGH-SPEED JFET-INPUT DUAL OPERATIONAL AMPLIFIER WITH SWITCHED-CAPACITOR VOLTAGE CONVERTER

TLE2682
HIGHĆSPEED JFETĆINPUT DUAL OPERATIONAL AMPLIFIER
WITH SWITCHEDĆCAPACITOR VOLTAGE CONVERTER
SLOS127 − JUNE 1993
APPLICATION INFORMATION
RIPPLE AND SWITCHING NOISE ON
SWITCHED-CAPACITOR OUTPUT
vs
TIME
200
150
100
50
0
− 50
RIPPLE AND SWITCHING NOISE ON
SWITCHED-CAPACITOR OUTPUT
vs
TIME
80
VCC+ = 5 V
60
IL = 10 mA
CIN = 100 µF
COUT = 100 µF
40
20
0
− 20
− 100
− 150
− 200
VCC+ = 5 V
IL = 10 mA
CIN = 100 µF
COUT = 10 µF
0 10 20 30 40 50 60 70 80 90 100
t − Time − µs
Figure 76
VOUT
COUT
+
− 40
− 60
− 80
0
10 20
30 40 50 60 70
t − Time − µs
Figure 77
80 90 100
LH
VCC
0.1 µF
CF
Filter
1
fr =
2 π LC
Figure 78. LC Filter Used to Reduce Ripple and Switching Noise,
f_r = 1/2π √LC, A = −40 dB per Decade
A low-pass LC filter can be added to the circuit to further reduce ripple and noise. For example, adding a filter as shown
in Figure 78, implemented using a 50-µH inductor and 200-µF capacitor (available in surface mount), achieves the
following results (see Figure 79 through Figure 82).
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