LTC1646
1
1646fa
■
CompactPCI Bus Removable Boards
■
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
CompactPCI Dual
Hot Swap Controller
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.
Figure 1
MMBT2222A
4.7nF
18Ω
18Ω
12Ω
10Ω
2.7Ω
1.8Ω
R3
10Ω
3k
R4
10Ω
3k
1k
R1
0.005Ω, 1%
R2
0.007Ω
1%
1k
R5
1k, 5%
10k
10k
3k
1.2k
3V
IN
PRECHARGE OUT
1V ±10%
I
OUT
= ± 55mA
3V
IN
3V
IN
3V
SENSE
5V
SENSE
3V
OUT
3V
OUT
5V
OUT
3.3V
5V
IN
5V
IN
5V
RESET#
I/O
PCI
BRIDGE
(21154)
DATA BUS
DATA BUS
V(I/O)
V(I/O)
0.1µF 0.1µF
0.1µF
C1
0.01µF
Q2
IRF7413
Q1
IRF7413
LOCAL_PCI_RST#
5V
5A
3.3V
7.6A
GATE
GND PRECHARGE DRIVE
RESETOUT
TIMER
OFF/ON
FAULT
PWRGD
RESETIN
LTC1646
15
891071211 5
2
1
613 14
3
4
16
BD_SEL#
HEALTHY#
PCI_RST#
1646 F01
DATA LINE EXAMPLE
COMPACT PCI
BACKPLANE
CONNECTOR
(MALE)
COMPACT PCI
CIRCUIT CARD
CONNECTOR
(FEMALE)
5V
LONG 5V
3.3V
LONG 3.3V
GROUND
I/O PIN 1
Z1, Z2: BZX84C6V2
Z2
Z1
APPLICATIO S
U
FEATURES
TYPICAL APPLICATIO
U
DESCRIPTIO
U
, 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.
