ltc1647-2 Linear Technology Corporation, ltc1647-2 Datasheet - Page 20

• Manufacturer Part Number: ltc1647-2
• Description: Dual Hot Swap Controllers
• Manufacturer: Linear Technology Corporation

RELATED PARTS
LTC1647-1/LTC1647-2/LTC1647-3
TYPICAL APPLICATIO
Hot Swapping Two Supplies
Two separate supplies can be independently controlled by
using the LTC1647-3. In some applications, sequencing
between the two power supplies is a requirement. For
example, it may be necessary to ramp-up one supply first
before allowing the second supply to power-up, as well as
requiring that this same supply ramp-down last on power-
down. Figure 14’s circuit illustrates how to program the
delays between the two pass transistors using the ON1
PART NUMBER
LTC1421
LTC1422
LT1640L/LT1640H
LT1641
LT1642
LTC1643L/LTC1643H
LT1645
20
12V SUPPLY
5V SUPPLY
FAULT
GND
ON1
ON2
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
[phone] FAX: [phone] www.linear-tech.com
R5
10k
DESCRIPTION
2-Channel Hot Swap Controller
Hot Swap Controller in SO-8
Negative Voltage Hot Swap Controller in SO-8
High Voltage Hot Swap Controller in SO-8
Fault Protected Hot Swap Controller
PCI-Bus Hot Swap Controller
2-Channel Hot Swap Controller
R6
10k
12k
R7
R4
4.7k
2
3
4
5
8
ON1
FAULT 1
ON2
FAULT 2
GND
V
V
U
CC1
CC2
1
16
0.01
0.02
R10
R1
LTC1647-3
SENSE 1
SENSE 2
Figure 14. Hot Swapping Two Supplies
15
14
R3
100
R8
100
IRF7413
IRF7413
GATE 1
GATE 2
Q2
Q1
13
12
R2
10
R9
10
+
+
C
C1
10nF
C3
10nF
C
LOAD
LOAD
V
(5A)
V
(2.5A)
OUT1
OUT2
and ON2 pins (time events t1 to t4). t5 and t7 show both
channels being switched on simultaneously where se-
quencing is not crucial.
Some applications require that both channels be gated off
if a fault occurs in one channel. This is accomplished in
Figure 14 by using a crisscross FAULT-to-SENSE arrange-
ment of R3/R4 and R7/R8. t6 and t9 illustrate the circuit’s
operation.
V
V
V
V
V
OUT1
OUT2
V
ON1
ON2
R10
R1
t1
COMMENTS
24-Pin, Operates from 3V to 12V and Supports –12V
System Reset Output with Programmable Delay
Operates from –10V to –80V
Operates from 9V to 80V
Operates Up to 16.5V, Protected to 33V
3.3V, 5V and 12V in Narrow 16-Pin SSOP
Operates from 1.2V to 12V, Power Sequencing
t2
t3
sn1647 1647fs LT/TP 0100 4K • PRINTED IN USA
t4
LINEAR TECHNOLOGY CORPORATION 1999
t5
t6
t7
t8
1647-1/2/3 F14
t9