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.
FEATURES
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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
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.
TYPICAL APPLICATIO
COMPACT PCI
BACKPLANE
CONNECTOR
(MALE)
5V
COMPACT PCI
CIRCUIT CARD
CONNECTOR
(FEMALE)
2.7Ω
Z1
Z2
R2
0.007Ω
1%
R1
0.005Ω, 1%
Q2
IRF7413
Q1
IRF7413
LONG 5V
3.3V
1.8Ω
LONG 3.3V
V(I/O)
0.1µF
0.1µF
R3
10Ω
8
3V
IN
9
10
7
3V
SENSE
GATE 3V
OUT
12
5V
IN
11
5V
SENSE
1.2k
BD_SEL#
V(I/O)
3k
HEALTHY#
PCI_RST#
3k
1k
15
3
4
16
OFF/ON
FAULT
LTC1646
PWRGD
RESETIN
GND
6
PRECHARGE
13
18Ω
4.7nF
18Ω
DRIVE
14
1k
12Ω
LOCAL_PCI_RST#
GROUND
10k
10Ω
I/O PIN 1
DATA BUS
Z1, Z2: BZX84C6V2
PRECHARGE OUT
1V
±10%
I
OUT
=
±
55mA
MMBT2222A
3V
IN
DATA LINE EXAMPLE
DATA BUS
Figure 1
U
U
U
5V
5A
3.3V
7.6A
R4
10Ω
5
5V
OUT
TIMER
2
R5
1k, 5%
C1
0.01µF
10k
0.1µF
3V
OUT
3k
RESETOUT
1
3V
IN
3.3V
RESET#
I/O
5V
IN
5V
PCI
BRIDGE
(21154)
1646 F01
1646fa
1
LINER [ LINEAR TECHNOLOGY ]
