Datasheet

R
C5
150
R
C5
150
R
C5
150
R
S
47
R
8
27k
R
5
47k
+1
R
2
10k
Offset
Trim
R
Q
250
V
IN
6
8
1
4
7
3
2
5
R
2
100k
R
1
100k
C
3
2.2
µ
F
D
1
D
2
V
OUT
OTA
+5V
5V
C
3
2.2pF
C
3
2.2
µ
F
5
1
4
BUF602
+5V
C
3
2.2
µ
F
5V
C
3
2.2
µ
F
+5V
5V
0.5pF
2.5pF
DMF3068A
Integrator for ns-Pulse
V
O
+
g
m
C
ŕ
T
O
V
BE
dt
(8)
V
C
+ V
BE
g
m
t
C
(7)
780W
V
I
OTA
50
kW
50W
3
2
E
C
8
+5V
-5V
V
O
27pF
1 Fm
620W
200W
820W
+1
65
B
OPA860
SBOS331C JUNE 2005 REVISED AUGUST 2008 .......................................................................................................................................................
www.ti.com
Figure 57. Comparator (Low Jitter)
One very interesting application using the OPA860 in
physical measurement technology is an open-loop
ns-integrator (shown in Figure 58 ) which can process
Where:
pulses with an amplitude of ± 2.5V, have a rise/fall
V
O
= Output Voltage
time of as little as 2ns, and also have a pulse width of
T = Integration Time
more than 8ns. The voltage-controlled current source
C = Integration Capacitance
charges the integration capacitor linearly according to
Equation 7 :
Where:
V
C
= Voltage At Pin 8
V
BE
= Base-Emitter Voltage
g
m
= Transconductance
t = Time
C = Integration Capacitance
The output voltage is the time integral of the input
voltage. It can be calculated from Equation 8 :
Figure 58. Integrator for ns-Pulses
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