LTC4244/LTC4244-1
Rugged, CompactPCI Bus
Hot Swap Controllers
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FEATURES
DESCRIPTIO
TheLTC®4244/LTC4244-1areHotSwapTM controllersthat
allow a board to be safely inserted into and removed from
a CompactPCITM bus slot. External N-channel transistors
control the 5V and 3.3V supplies while on-chip switches
■
Controls –12V, 3.3V, 5V and 12V Supplies
■
±14.4V Absolute Maximum Rating for 12VIN
and –12VIN Input Pins
Insensitive to Supply Voltage Transients
■
■
Adjustable Foldback Current Limit with Circuit Breaker control the ±12V supplies. The 3.3V and 5V supplies can
■
■
LOCAL_PCI_RST# Logic On-Chip
PRECHARGE Output Biases I/O Pins During Card
Insertion and Extraction
LTC4244-1 Designed for Applications without –12V
Available in 20-Lead Narrow SSOP Package
be ramped up at an adjustable rate. Electronic circuit
breakers protect all four supplies against overcurrent
faults.Afterthepower-upcycleiscomplete,theTIMERpin
capacitor serves as auxiliary VCC allowing the LTC4244/
LTC4244-1 to function without interruption in the pres-
ence of voltage spikes on the 12VIN supply. The PWRGD
output indicates when all four supplies are within toler-
ance. TheOFF/ONpinisusedtocycleboardpowerorreset
the circuit breaker. The PRECHARGE output can be used
to bias the bus I/O pins during card insertion and extrac-
tion. PCI_RST# is combined on-chip with HEALTHY# in
order to generate LOCAL_PCI_RST#.
■
■
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APPLICATIO S
■ Hot Board Insertion into CompactPCI Bus
, LTC and LT are registered trademarks of Linear Technology Corporation.
Hot Swap is a trademark of Linear Technology Corporation.
CompactPCI is a trademark of the PCI Industrial Computer Manufacturers Group.
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TYPICAL APPLICATIO
C8
C9
0.01µF PER
POWER PIN
0.01µF PER
POWER PIN
R2
Q2
5V
IN
0.007Ω IRF7457
V
5V
5A
OUT
5V
+
+
R22
C
C
R1
0.005Ω
Q1
2.7Ω
LOAD(5VOUT)
LONG 5V
3.3V
IRF7457
V
3.3V
7A
3.3V
OUT
IN
R21
1.8Ω
Z3
LOAD(3.3VOUT)
C1
LONG 3.3V
R4
10Ω
R3
10Ω
Z4
C6
0.01µF
C7
0.01µF
R5
1k
0.33µF
Z1
Z2
3.3V
3.3V
SENSE
GATE 3.3V
5V
5V
5V
12V
IN
OUT
IN
SENSE
OUT
V
OUT
12V
V
12V
12V
IN
OUT
+
500mA
–12V
EEIN
C
C
LOAD(12VOUT)
R19 1k
V
OFF/ON
FAULT
BD_SEL#
EEOUT
V
–12V
R20
1.2k
EEOUT
R18 10k
LTC4244
100mA
LOAD(VEEOUT)
+
LONG V(I/O)
R17
10k
TIMER
C2
0.082µF
PWRGD
HEALTHY#
PCI_RST#
R6
RESETIN
10k
V
OUT
3.3V
GND PRECHARGE
RESETOUT
R8 1k
DRIVE
Q3
R15
R16
1Ω
C5
0.01µF
LOCAL_PCI_RST#
R9 24Ω
1Ω
C3 4.7nF
C4
0.01µF
V
IN
3.3V
GROUND
R10 18Ω
R7 12Ω
R11
10k
R12
10k
R13
10Ω
MMBT2222A
1V
±10%
RESET#
I/O DATA LINE 1
I/O #1
I/O PIN 1
PCI
BRIDGE
CHIP
•
•
•
•
•
•
•
•
•
R14
10Ω
I/O #128
I/O DATA LINE 128
I/O PIN 128
Z1, Z2: SMAJ12A Z3, Z4: SMAJ5.0A
4244 F01
Figure 1. Typical Compact PCI Application
42441f
1