LT1640LCN8 Linear Technology, LT1640LCN8 Datasheet - Page 10

• Manufacturer Part Number: LT1640LCN8
• Description: IC CONTRLR HOTSWAP NEGVOLT 8-DIP
• Manufacturer: Linear Technology
• Type: Hot-Swap Controllerr

Specifications of LT1640LCN8

• Applications: General Purpose
• Internal Switch(s): No
• Voltage - Supply: -10 V ~ -80 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Through Hole
• Package / Case: 8-DIP (0.300", 7.62mm)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

APPLICATIONS
LT1640L/LT1640H
Under some conditions, a short circuit at the output can
cause the input supply to dip below the UV threshold,
resetting the circuit breaker immediately.
The LT1640 then cycles on and off repeatedly until the
short is removed. This can be minimized by adding a
deglitching delay to the UV pin with a capacitor from UV to
V
resistors at UV, allowing the input supply to recover before
the UV pin resets the circuit breaker.
A circuit that automatically resets the circuit breaker after
a current fault is shown in Figure 9.
10
EE
. This capacitor forms an RC time constant with the
* DIODES INC. SMAT70A
– 48V
GND
*
U
1N4148
D1
INFORMATION
2N2222
U
Q2
100V
1 F
C4
1M
5%
R7
50V/DIV
NODE 2
3
2V/DIV
GATE
R8
510k
5%
W
ZVN3310
(SHORT PIN)
2
Figure 9. Automatic Restart After Current Fault
Q3
GND
562k
10k
1%
1%
R6
R9
U
19.1k
562k
1%
1%
R4
R5
3
2
1s/DIV
UV
OV
3
V
EE
4
1
Transistors Q2 and Q3 along with R7, R8, C4 and D1 form
a programmable one-shot circuit. Before a short occurs,
the GATE pin is pulled high and Q3 is turned on, pulling
node 2 to V
occurs, the GATE pin is pulled low and Q3 turns off. Node
2 starts to charge C4 and Q2 turns on, pulling the UV pin
low and resetting the circuit breaker. As soon as C4 is fully
charged, R8 turns off Q2, UV goes high and the GATE
starts to ramp up. Q3 turns back on and quickly pulls node
2 back to V
below V
overheating.
0.02
5%
R1
SENSE
2
4
5
EE
. The duty cycle is set to 10% to prevent Q1 from
EE
EE
C1
150nF
25V
LT1640L
. Diode D1 clamps node 3 one diode drop
GATE
. Resistor R8 turns off Q2. When a short
V
DD
1640 F09b
8
6
IRF530
Q1
R2
10
5%
18k
5%
R3
1N4148
3.3nF
100V
C2
PWRGD
DRAIN
7
1
+
1640 F09a
C3
100 F
100V
1640lhfb