TL081C,AC TL082C,AC TL084C,AC
Figure 14. Positive Peak Detector
Figure 15. Voltage Controlled Current Source
R3
–
–
1/2
TL082
Vin
VO
R1
+
TL081
R5
IO
1/2
TL082
–
R2
R4
+
1N914
*
1.0
µF
Vin
+
Reset
*Polycarbonate or
Polystyrene Capacitor
If R1 through R4 > > R5 then Iout =
Vin
R5
Figure 16. Long Interval RC Timer
Figure 17. Isolating Large Capacitive Loads
R2 5.1 k
VO
R1
VR
R4
V1
R2
R3
–
TL081
6
R1 5.1 k
R6
–
TL081
+
+2.0 V
0
–2.0 V
*Polycarbonate or
Polystyrene Capacitor
•
•
•
•
CC 20 pF
IO
R3 10
RL 5.1 k
CL 0.5
µF
+
Clear
Run
C*
R5
Overshoot
10%
ts = 10
µs
When driving large CL, the VO slew rate is determined by CL
and IO(max):
∆V
O IO
=
∆t
CL
t
Time (t) = R4 C n (VR/VR–VI), R3 = R4, R5 = 0.1 R6
If R1 = R2: t = 0.693 R4C
Design Example: 100 Second Timer
VR = 10 V C = l.0 mF
R3 = R4 = 144 M
R6 = 20 k R5 = 2.0 k
R1 = R2 = 1.0 k
^
0.02
0.5
V/µs = 0.04 V/µs (with CL shown)
2–330
MOTOROLA ANALOG IC DEVICE DATA
ROCHESTER [ Rochester Electronics ]
