LTC1643AL-1_15 Datasheet, PDF (1/16 Pages) Linear Technology – PCI-Bus Hot Swap Controller

FEATURES
■ _{Allows Safe Board Insertion and Removal from a}
Live PCI Slot
■ _{Works on either a Motherboard (LTC1643AH) or}
CompactPCI^TM 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}
U
APPLICATIO S
■ _{PCI-Based Servers}
■ _{CompactPCI Compliant Boards}
, 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.
LTC1643AL
LTC1643AL-1/LTC1643AH
PCI-Bus Hot Swap
Controller
DESCRIPTIO
The LTC^®1643A is a Hot Swap^TM controller that allows a board
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. All supply voltages can be ramped up at a program-
mable rate. An electronic circuit breaker protects all four
supplies against overcurrent faults. The foldback current limit
feature limits current spikes and power dissipation when
shorts occur and allows boards with large capacitances to be
powered up without tripping the circuit breaker. The PWRGD
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.
The LTC1643A is available in a 16-pin narrow SSOP package.
TYPICAL APPLICATION
Hot Swappable PCI Supply
R1
Q1
0.007Ω IRF7413
R2
Q2
R6
0.005Ω IRF7413
10Ω
SYSTEM
POWER
R5
SUPPLY
10Ω
9
10
11
3
13
12
PCI
POWER
SYSTEM
CONTROLLER
8 ^3VIN
GND
1
2
12V_IN
V_EEIN
3V_SENSE GATE 3V_OUT 5V_IN
5V_SENSE
5
ON
R3
LTC1643AH
10k ₆
FAULT
R4
10k _{7 PWRGD}
RESET
R7
100Ω
14
5V_OUT
16
12V_OUT
15
V_EEOUT
4
TIMER
5V
5A
3.3V
7.6A
GND
C1
0.047µF
12V
500mA
–12V
100mA
C2
0.1µF
LOGIC
RESET
1643A TA01
1643afb
1