APPLICATIONS INFORMATION
LT1720/LT1721
X
0.1µF
Y
51Ω*
R9
487Ω*
51Ω*
DELAY DETECTOR
5V
+
U1A
1/4 LT1721
–
R8*
4.53k
5V
301Ω*
R5
1.82k*
R6
301Ω*
301Ω*
C1
5.6pF
–
U1C
1/4 LT1721
+
–
U1B
1/4 LT1721
+
301Ω*
R7
261Ω*
OPTIONAL LOGARITHMIC PULSE STRETCHER (SEE TEXT)
5V
CAPTURE
Z
1N5711
R1
499Ω*
VIN
VC
C2
540pF
**
5V
0.33µF
+
U1D
1/4 LT1721
L
–
475Ω*
+
R2
R3
1k*
1Ω* VOFF
–
X 1V
0V
Y 1V
0V
Z 5V
0V
DELAY
R4
30Ω*
* 1% METAL FILM RESISTOR
** 270pF ×2 FOR REDUCED LEAD INDUCTANCE
1720/21 F12
RESULT OF X AND NOT Y
Figure 12. 3ns Delay Detector with Logarithmic Pulse Stretcher
X
Y
Z
Figure 13. Output Pulse Due to Delay of Y Input Pulse
17