LTC1643AL
LTC1643AL-1/LTC1643AH
PCI-Bus Hot Swap
Controller
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FEATURES
DESCRIPTIO
TheLTC®1643AisaHotSwapTM controllerthatallowsaboard
to be safely inserted and removed from a live PCI-Bus slot.
Two external N-channel transistors control the 3.3V and 5V
supplies while on-chip switches control the –12V and 12V
supplies. Allsupplyvoltagescanberampedupataprogram-
mable rate. An electronic circuit breaker protects all four
suppliesagainstovercurrentfaults.Thefoldbackcurrentlimit
feature limits current spikes and power dissipation when
shortsoccurandallowsboardswithlargecapacitancestobe
poweredupwithouttrippingthecircuitbreaker. ThePWRGD
output indicates when all of the supply voltages are within
tolerance and the FAULT output indicates an overcurrent
condition. The ON(LTC1643AH)/ON (LTC1643AL/
LTC1643AL-1) pin is used to cycle the board power or reset
the circuit breaker. The LTC1643AL-1 has the ±12V power
good comparators disabled.
■
Allows Safe Board Insertion and Removal from a
Live PCI Slot
■
Works on either a Motherboard (LTC1643AH) or
CompactPCITM Card (LTC1643AL/LTC1643AL-1)
■
Controls –12V, 3.3V, 5V, 12V Supplies
■
Programmable Foldback Current Limit with
Circuit Breaker
■
User-Programmable Supply Voltage Power-Up Rate
■
High Side Drive for External N-Channel MOSFETs
■
–12V and 12V On-Chip Switches
Fault and Power-Good Outputs
■
■
Available in a Narrow 16-Lead SSOP Package
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APPLICATIO S
■
PCI-Based Servers
CompactPCICompliant Boards
■
TheLTC1643Aisavailableina16-pinnarrowSSOPpackage.
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
Hot Swap is a registered trademark of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
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TYPICAL APPLICATION
Hot Swappable PCI Supply
R1
0.007Ω
Q1
IRF7413
5V
5A
R6
10Ω
R2
0.005Ω
Q2
IRF7413
3.3V
7.6A
GND
SYSTEM
POWER
SUPPLY
R5
10Ω
R7
100Ω
C1
0.047µF
9
10
11
3
13
12
14
3V
IN
3V
GATE 3V
5V
IN
5V
5V
OUT
SENSE
OUT
SENSE
8
GND
1
2
12V
IN
V
EEIN
16
5
6
7
12V
12V
OUT
ON
500mA
LTC1643AH
R3
15
4
–12V
100mA
V
EEOUT
10k
PCI
FAULT
POWER
SYSTEM
CONTROLLER
TIMER
R4
10k
C2
0.1µF
PWRGD
LOGIC
RESET
RESET
1643A TA01
1643afb
1