LTC4245_15 Datasheet, PDF (1/36 Pages) Linear Technology – Multiple Supply Hot Swap Controller with I2C Compatible Monitoring

FEATURES
■ _{Allows Safe Insertion into Live CompactPCI}^TM _or
PCI Express^TM Backplane
■ _{8-Bit ADC Monitors Current and Voltage}
■ _I²_C^TM_{/SMBus Interface}
■ _{dI/dt Controlled Soft Start}
■ _{Simultaneous or Sequenced Turn-On}
■ _{±20V Absolute Maximum Rating for ±12V Supplies}
■ _{No External Gate Capacitor Required}
■ _{Dual-Level Circuit Breaker and Current Limit}
■ _{Bus Precharge Output}
■ _{Power Good Input with Timeout}
■ _{Optional Latchoff or Autoretry After Faults}
■ _{Alerts Host After Faults}
■ _{Integrated LOCAL_PCI_RST# Logic}
■ _{36-Pin SSOP and 38-Pin (5mm × 7mm) QFN}
Packages
U
APPLICATIO S
■ _{Live Board Insertion}
■ _{CompactPCI, CompactPCI Express, CompactTCA,}
PCI Express Systems
LTC4245
Multiple Supply Hot Swap
Controller with I²C
Compatible Monitoring
DESCRIPTIO
The LTC^®4245 Hot Swap^TM controller allows a board to
be safely inserted and removed from a live backplane in
multiple supply systems such as CompactPCI and PCI
Express. Using four external N-channel pass transistors,
the board supply voltages can be ramped up at an adjust-
able rate and in any desired sequence. An I²C interface and
onboard ADC allow monitoring of board current, voltage
and fault status for each supply.
The device features adjustable dI/dt controlled soft start
and foldback limited inrush current. A dual-level timed
circuit breaker and fast current limit protect each supply
against overcurrent faults. A power good input with timeout
allows a downstream supply monitor to disconnect the
board supplies. The device can be configured to function
without a –12V supply or with an extra 3.3V supply instead
of a 5V supply.
The controller has additional features to interrupt the host
when a fault has occurred, notify when output power is
good, detect insertion of a load card and power-up in
either the on or off state.
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
TYPICAL APPLICATIO
CompactPCI Application
BACKPLANE CARD
CONNECTOR CONNECTOR
5V_OUT
12V_OUT
Sequenced Turn-On Waveform
BD_SEL#
10V/DIV
12V_IN 12V_SENSE 12V_GATE 12V_OUT 5V_IN 5V_SENSE 5V_GATE
BD_SEL#
5V_OUT
ON
HEALTHY#
SDA
SCL
ALERT#
PCI_RST#
LTC4245
PGI
LOCAL_PCI_RESET#
PRECHARGE
GND
3V_OUT
V_EEIN V_EESENSE V_EEGATE V_EEOUT 3V_IN 3V_SENSE 3V_GATE
SUPPLY
MONITOR
RESET
BOARD
RESET
TO BUS
–12V_OUT
3.3V_OUT
OUTPUT
VOLTAGE
5V/DIV
LOCAL_PCI_RST#
5V/DIV
12V_OUT
5V_OUT
3V_OUT
V_EEOUT
TIME (50ms/DIV)
4245 TA01b
4245fa
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