1
LTC4244/LTC4244-1
42441f
APPLICATIO S
FEATURES
TYPICAL APPLICATIO
DESCRIPTIO
s
Controls 12V, 3.3V, 5V and 12V Supplies
s
?SPAN class="pst LTC4244CGN-1-TRPBF_2334241_5">14.4V Absolute Maximum Rating for 12V
IN
and 12V
IN
Input Pins
s
Insensitive to Supply Voltage Transients
s
Adjustable Foldback Current Limit with Circuit Breaker
s
LOCAL_PCI_RST# Logic On-Chip
s
PRECHARGE Output Biases I/O Pins During Card
Insertion and Extraction
s
LTC4244-1 Designed for Applications without 12V
s
Available in 20-Lead Narrow SSOP Package
, LTC and LT are registered trademarks of Linear Technology Corporation.
s  Hot Board Insertion into CompactPCI Bus
The LTC
?/DIV>
4244/LTC4244-1 are Hot Swap
TM
controllers that
allow a board to be safely inserted into and removed from
a CompactPCI
TM
bus slot. External N-channel transistors
control the 5V and 3.3V supplies while on-chip switches
control the ?2V supplies. The 3.3V and 5V supplies can
be ramped up at an adjustable rate. Electronic circuit
breakers protect all four supplies against overcurrent
faults. After the power-up cycle is complete, the TIMER pin
capacitor serves as auxiliary V
CC
allowing the LTC4244/
LTC4244-1 to function without interruption in the pres-
ence of voltage spikes on the 12V
IN
supply. The PWRGD
output indicates when all four supplies are within toler-
ance. The OFF/ON pin is used to cycle board power or reset
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#.
3.3V
IN
12V
IN
12V
OUT
V
EEIN
OFF/ON
Z4
5V
IN
R4
10&
C
LOAD(5VOUT)
V
OUT
5V
5A
V
OUT
3.3V
7A
R5
1k
C1
0.33礔
R3
10&
R1
0.005&
R2
0.007&
Q1
IRF7457
Q2
IRF7457
3.3V
OUT
3.3V
SENSE
GND  PRECHARGE
5V
IN
5V
SENSE
DRIVE
R9 24&
1V
?0%
Q3
MMBT2222A
C3 4.7nF
V
IN
3.3V
4244 F01
LTC4244
GATE
5V
OUT
+
C
LOAD(3.3VOUT)
+
V
OUT
12V
500mA
C
LOAD(12VOUT)
+
V
EEOUT
TIMER
RESETOUT
I/O #1
I/O #128
V
EEOUT
12V
100mA
V
OUT
3.3V
C
LOAD(VEEOUT)
C2
0.082礔
Z3
Z2
Z1
R17
10k
3.3V
IN
R22
2.7&
C9
0.01礔 PER
POWER PIN
C7
0.01礔
C8
0.01礔 PER
POWER PIN
R21
1.8&
R19 1k
FAULT
PWRGD
RESETIN
R18 10k
R20
1.2k
R16
1&
C6
0.01礔
R8 1k
R7 12&
R6
10k
R10 18&
R11
10k
R13
10&
R14
10&
"
"
"
"
"
"
"
"
"
R12
10k
C5
0.01礔
R15
1&
C4
0.01礔
I/O DATA LINE 1
I/O DATA LINE 128
Z1, Z2: SMAJ12A    Z3, Z4: SMAJ5.0A
I/O PIN 128
RESET#
PCI
BRIDGE
CHIP
I/O PIN 1
GROUND
PCI_RST#
LOCAL_PCI_RST#
HEALTHY#
LONG V(I/O)
BD_SEL#
12V
12V
LONG 3.3V
LONG 5V
3.3V
5V
Figure 1. Typical Compact PCI Application
Hot Swap is a trademark of Linear Technology Corporation.
CompactPCI is a trademark of the PCI Industrial Computer Manufacturers Group.
Rugged, CompactPCI Bus
Hot Swap Controllers