LTC1421 LINER [Linear Technology], LTC1421 Datasheet - Page 17

• Manufacturer Part Number: LTC1421
• Description: Hot Swap Controller
• Manufacturer: LINER [Linear Technology]

APPLICATIONS
5V Only Applications
The LTC1421 may be used in 5V only applications as shown
in Figure 18. A soft reset can be generated from the
backplane via an open-collector inverter driving the FB (Pin
11) or by a push button to ground. A hard power reset is
generated from the backplane via an open-collector inverter
driving the POR (Pin 3). A hard reset cycles the power on
the board or resets the electronic circuit breaker. The
comparator is used to monitor the board supply voltage and
– 48V
– 48V
– 48V
BACKPLANE
POWERGOOD
HARD RESET
SOFT RESET
FAULT
U
PC BOARD
INFORMATION
5V
5V
1/6
LS7004
U
10k
10k
5V
D1
5V
BACKPLANE
– 48V
S1
R1
5k
1W
+
+
W
C1
1 F
C2
2.2 F
25V
24
Figure 18. 5V Only Application with Soft Reset
PC BOARD
Figure 19. – 48V to 5V Hot Swappable Supply
2
4
3
1
23
12
22
+
U
21
LTC1421
C1
1 F
5
20
24
15
2
1
19
0.005
12
18
23
1W
R1
2.2 F
17
25V
C3
22
5
MTB50N06E
16
will pull the POWERGOOD signal low as long as the supply
remains above 4.65V. Note that a soft reset will not affect
the POWERGOOD signal. The FAULT signal is also moni-
tored to determine that the circuit breaker has tripped.
– 48V and 24V Applications
The LTC1421 may be used in – 48V applications as shown
in Figure 19. The LTC1421 provides the hot insertion
protection, while the 5V supply is generated by a power
+
10
9
13
14
8
11
15
6
7
Q1
LTC1421
21
9
300
1/8W
R4
20
6
R2
15k
1/8W
19
3
IRFR9110
18
Q1
Q2
MPSA06
R3
56k
1/2W
17
16
LTC1421/LTC1421-2.5
10
7
14
13
8
11
R5
10k
1/2W
R6
400
1/8W
+
C2
1 F
C4
100 F
100V
S1
1421 F18
R2
28k
1%
R3
10.2k
1%
1
2
1421 F19
+IN
–IN
ASD 10-48S5
ASTRODYNE
C2
2200 F
CONTROL
RESET
LOGIC
– OUT
6
+OUT
5V
3
5
+
C4
100 F
16V
5V
2A
17