LT4250HCS8 Linear Technology, LT4250HCS8 Datasheet - Page 10

• Manufacturer Part Number: LT4250HCS8
• Description: IC CONTRLR HOTSWAP NEG 48V 8SOIC
• Manufacturer: Linear Technology
• Type: Hot-Swap Controllerr

Specifications of LT4250HCS8

• Applications: General Purpose
• Internal Switch(s): No
• Voltage - Supply: -20 V ~ -80 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (0.154", 3.90mm Width)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

APPLICATIONS INFORMATION
LT4250L/LT4250H
A circuit that automatically resets the circuit breaker after
a current fault is shown in Figure 10. 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
Resistor R8 turns off Q2. When a short occurs, the GATE
pin is pulled low and Q3 turns off. Node 2 starts to charge
10
Figure 8. Voltage Step on Input Supply Waveforms
V
20V/DIV
EE
I
5A/DIV
DRAIN
D
AND
(Q1)
–48V RTN
* DIODES INC. SMAT70A
–48V
*
500μs/DIV
1N4148
D1
2N2222
Q2
100V
1μF
C4
1M
5%
R7
3
Figure 10. Automatic Restart After Current Fault
R8
510k
5%
4250 08
ZVN3310
(SHORT PIN)
2
50V/DIV
NODE 2
–48V RTN
2V/DIV
Q3
GATE
549k
1%
R6
10k
1%
R9
16.5k
549k
1%
1%
R4
R5
EE
.
3
2
UV
OV
3
V
EE
–48V RTN
4
1s/DIV
1
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
D1 clamps node 3 one diode drop below V
cycle is set to 10% to prevent Q1 from overheating.
0.02Ω
* DIODES INC. SMAT70A
5%
R1
–48V
(SHORT PIN)
Figure 9. Circuit for Input Steps with Small C2 (<10nF)
–48V RTN
SENSE
2
*
4
5
6.49k
549k
10k
1%
1%
1%
R4
R5
R6
C1
470nF
25V
LT4250L
V
3
2
DD
4250 F10
8
IRF530
GATE
UV
OV
3
V
Q1
EE
4
6
R2
10Ω
5%
1
0.02Ω
5%
R1
1k, 5%
R3
SENSE
2
15nF
100V
220Ω
4
5
C2
PWRGD
5%
DRAIN
R7
7
LT4250H
BAT85
V
C1
150nF
25V
DD
D1
1
8
GATE
+
6
IRF530
Q1
4250 F10a
C3
100μF
100V
R2
10Ω
5%
5%
R3
1k
3.3nF
100V
C2
PWRGD
DRAIN
7
1
EE
. The duty
EE
C3
0.1μF
100V
4250 F09
. Diode
+
4250lhfa
C4
22μF
100V