LTC1646 Datasheet, PDF (1/20 Pages) Linear Technology – CompactPCI Dual Hot Swap Controller

FEATURES
■ _{Allows Safe Board Insertion and Removal from a}
Live, CompactPCI^TM Bus
■ _{Controls 3.3V and/or 5V Supplies}
■ _{Programmable Foldback Current Limit During}
Power-Up
■ _{Dual Level Circuit Breakers Protect Supplies from}
Overcurrent and Short-Circuit Faults
■ _{LOCAL_PCI_RST# Logic On-Chip}
■ _{PRECHARGE Output Biases I/O Pins During Card}
Insertion and Extraction
■ _{User Programmable Supply Voltage Power-Up Rate}
■ _{15V High Side Drive for External N-Channel}
MOSFETS
■ _{PWRGD, RESETOUT and FAULT Outputs}
U
APPLICATIO S
■ _{CompactPCI Bus Removable Boards}
, LTC and LT are registered trademarks of Linear Technology Corporation.
Hot Swap is a trademark of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
LTC1646
CompactPCI Dual
Hot Swap Controller
DESCRIPTIO
The LTC^®1646 is a Hot Swap^TM controller that allows a
board to be safely inserted and removed from a live
CompactPCI bus slot. Two external N-Channel transistors
control the 3.3V and 5V supplies. The supplies can be
ramped-up in current limit or a programmable rate. Elec-
tronic circuit breakers protect both supplies against
overcurrent fault conditions. The PWRGD output indicates
when all of the supply voltages are within tolerance. The
OFF/ON pin is used to cycle the board power or reset the
circuit breaker. The PRECHARGE output can be used to
bias the bus I/O pins during card insertion and extraction.
PCI_RST# is logically combined on-chip with HEALTHY#
in order to generate LOCAL_PCI_RST# which can be used
to reset the CPCI card logic if either of the supply voltages
is not within tolerance.
The LTC1646 is available in the 16-pin narrow SSOP
package.
TYPICAL APPLICATIO
5V
LONG 5V
3.3V
LONG 3.3V
COMPACT PCI
BACKPLANE
CONNECTOR
(MALE)
COMPACT PCI
CIRCUIT CARD
CONNECTOR
(FEMALE)
2.7Ω
1.8Ω
V(I/O)
BD_SEL#
HEALTHY#
PCI_RST#
1.2k
V(I/O)
3k
Z1
Z2
R1
Q2
0.005Ω, 1% IRF7413
R2
0.007Ω Q1
1% IRF7413
0.1µF
1k
3k
0.1µF
R3
10Ω
8
9
10 7 12
3V_IN 3V_SENSE GATE 3V_OUT 5V_IN
15 _OFF/ON
11
5V_SENSE
R4
10Ω
R5
1k, 5%
5
5V_OUT
2 ^10k
TIMER
3 _FAULT
4 _PWRGD
16 _RESETIN
GND
6
LTC1646
PRECHARGE
13
DRIVE
18Ω
14
3V_OUT
3k
1
RESETOUT
1k
5V
5A
3.3V
7.6A
C1
0.01µF
0.1µF
GROUND
I/O PIN 1
DATA BUS
Z1, Z2: BZX84C6V2
18Ω
4.7nF
12Ω
PRECHARGE OUT MMBT2222A
10k
1V ±10%
I_OUT = ± 55mA
3V_IN
10Ω
DATA LINE EXAMPLE
DATA BUS
Figure 1
3V_IN 5V_IN
3.3V 5V
RESET#
I/O _PCI
BRIDGE
(21154)
1646 F01
1646fa
1