LTC4244_15 Datasheet, PDF (1/28 Pages) Linear Technology – Rugged, CompactPCI Bus Hot Swap Controllers

LTC4244/LTC4244-1
Rugged, CompactPCI Bus
Hot Swap Controllers
FEATURES
DESCRIPTIO
s _{Controls –12V, 3.3V, 5V and 12V Supplies}
s _{±14.4V Absolute Maximum Rating for 12VIN}
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}
U
APPLICATIO S
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.
The LTC^®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 ±12V 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#.
TYPICAL APPLICATIO
5V
LONG 5V
3.3V
LONG 3.3V
12V
–12V
BD_SEL#
LONG V(I/O)
HEALTHY#
PCI_RST#
GROUND
I/O PIN 1
•••
I/O PIN 128
C8
0.01µF PER
POWER PIN
C9
0.01µF PER
POWER PIN
5V_IN
C6
0.01µF
R22
2.7Ω
R21
1.8Ω
C7
0.01µF
3.3V_IN
R1
0.005Ω
Z3
Z4
Q1
IRF7457
R3
10Ω
R2
Q2
0.007Ω IRF7457
R4
10Ω
+
C_LOAD(5VOUT)
+
C_{LOAD(3.3VOUT)}
C1
R5 _0.33µF
1k
V_OUT
5V
5A
V_OUT
3.3V
7A
Z1
R17
10k
R15
1Ω
C4
0.01µF
I/O DATA LINE 1
I/O DATA LINE 128
Z2
R20
1.2k
R16
1Ω
C5
0.01µF
•••
R19 1k
R18 10k
3.3V_IN
12V_IN
V_EEIN
3.3V_SENSE GATE 3.3V_OUT 5V_IN
5V_SENSE
OFF/ON
FAULT
LTC4244
5V_OUT
12V_{OUT +}
V_EEOUT
C_LOAD(12VOUT)
C_LOAD(VEEOUT)
V_OUT
12V
500mA
V_EEOUT
–12V
100mA
PWRGD
RESETIN
GND PRECHARGE
C3 4.7nF
TIMER
C2
0.082µF
DRIVE RESETOUT
LOCAL_PCI_RST#
R9 24Ω
R8 1k
R6
10k _VOUT
3.3V
R13
10Ω
R10 18Ω
R11
10k
R12
10k
Q3 _{R7 12Ω}
1V MMBT2222A
±10%
R14
10Ω
•••
V_IN
3.3V
RESET#
I/O #1
PCI
BRIDGE
I/O #128 _CHIP
Z1, Z2: SMAJ12A Z3, Z4: SMAJ5.0A
4244 F01
Figure 1. Typical Compact PCI Application
42441f
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