LTC4241_15 Datasheet, PDF (1/16 Pages) Linear Technology – PCI-Bus with 3.3V Auxiliary Hot Swap Controller

FEATURES
s _{Allows Safe Board Insertion and Removal from a}
Live PCI Slot
s _{Controls 3.3V, 5V, –12V, 12V and 3.3V Auxiliary}
Supplies
s _{Independent 3.3V Auxiliary Supply Hot Swap}^TM
Controller
s _{Adjustable Foldback Current Limit with Circuit}
Breaker
s _{Adjustable Supply Voltage Power-Up Rate}
s _{High Side Drive for External N-Channel FETs}
s _{–12V and 12V On-Chip Switches}
s _{Fault and Power Good Outputs}
U
APPLICATIO S
s _{PCI-Based Servers}
s _{Computer Systems}
, LTC and LT are registered trademarks of Linear Technology Corporation.
Hot Swap is a trademark of Linear Technology Corporation.
LTC4241
PCI-Bus with 3.3V Auxiliary
Hot Swap Controller
DESCRIPTIO
The LTC^®4241 is a Hot Swap controller that allows a board
to be safely inserted and removed from a live PCI-bus slot.
It has a primary controller that controls the four PCI
supplies and an independent auxiliary controller to control
the 3.3V auxiliary supply. External N-channel transistors
are used to control the 3.3V, 5V and 3.3V auxiliary supplies
while on-chip switches control the –12V and 12V supplies.
The 3.3V, 5V and 3.3V auxiliary supplies can be ramped up
at an adjustable rate. Electronic circuit breakers protect all
five supplies against overcurrent faults. The foldback
current limit feature reduces current spikes and power
dissipation when shorts occur. The PWRGD output of the
primary controller indicates when all four PCI supplies are
within tolerance. The FAULT output indicates an overcurrent
condition for any of the five supplies.
The LTC4241 is available in the 20-pin narrow SSOP
package.
TYPICAL APPLICATIO
GND
R1
Q1
5V
0.007Ω IRF7413
5A
R2
0.005Ω
Q2
IRF7413
R4
3.3V
10Ω
7.6A
SYSTEM
POWER
SUPPLY
PCI
POWER
SYSTEM
CONTROLLER
RESET
R3
Q3
R5
0.07Ω
Si2306DS
10Ω
3.3V_AUX
500mA
C3
10nF
R6
10Ω
11
10
9
13
14 15 3
8 ^{AUXIN AUXSENSE AUXGATE 3VIN 3VSENSE GATE 3VOUT}
GND
1
2 ^12VIN
12 ^VEEIN
AUXON
5
ON
LTC4241
R8 10k
17
16 18
5V_IN 5V_SENSE 5V_OUT
20
12V_OUT
19
V_EEOUT
6
R9 10k
FAULT
4
TIMER
7
PWRGD
R7
100Ω
C1
0.047µF
12V
500mA
–12V
100mA
BACKPLANE
C2 ^CONNECTOR
0.1µF
LOGIC
RESET
4241 F01
Figure 1. Hot Swappable PCI and 3.3V Auxiliary Supplies
sn4241 4241f
1