Datasheet

LTC4365
15
4365fa
For more information www.linear.com/LTC4365
applicaTions inForMaTion
Transients During OV Fault
The circuit of Figure 15 was used to display transients
during an overvoltage condition. The nominal input supply
is 24V and it has an overvoltage threshold of 30V. The
parasitic inductance is that of a 1 foot wire (roughly 300nH).
Figure 16 shows the
waveforms during an overvoltage
condition at V
IN
. These transients depend on the parasitic
inductance and resistance of the wire along with the ca-
pacitance at
the V
IN
node. D1 is an optional power clamp
(TVS, Tranzorb) recommended for applications where
the DC input voltage can exceed 24V and with large V
IN
parasitic inductance. No clamp was used to capture the
waveforms of Figure 16. In order to maintain reverse sup
-
ply protection, D1 must be a bi-directional clamp rated for
at least 225W peak pulse power dissipation.
V
IN
UV
OV
SHDN
OV = 30V
4365 F15
V
OUT
FAULT
GATE
M1 M2
V
IN
24V
SI9945
60V
12 INCH WIRE
LENGTH
V
OUT
GND
LTC4365
R2
2370k
R1
40.2k
R3
100k
C
OUT
100µF
+
C
IN
1000µF
D1
OPTIONAL
+
9Ω
2A/DIV
GND
GND
0A
20V/DIV
20V/DIV
4365 F16
250ns/DIV
GATE
V
OUT
V
IN
I
IN
GATE
V
OUT
Figure 15. OV Fault with Large V
IN
Inductance
Figure 16. Transients During OV Fault When No
Tranzorb (TVS) Is Used