LTC4240

Features:

Allows Safe Board Insertion and Removal from a Live CompactPCI^TM Bus
I²C^TM Compatible 2-Wire Interface
PRECHARGE Output Biases I/O Pins During Card Insertion and Extraction
Controls 3.3V, 5V, 12V and 12V Supplies
Foldback Current Limit with Circuit Breaker
LOCAL_PCI_RST# Logic On-Board
QuickSwitch^® Enable Output
Status LED Driver
User Programmable Supply Voltage Power-Up Rate
Registers Individual Supply Faults
Available in a 28-Pin Narrow SSOP Package


Application

Hot Board Insertion into CompactPCI Bus
Electronic Circuit Breaker


Pinout




Specifications

Supply Voltages
5V_IN....................................................................0.3V to 12V
12V_IN.................................................................0.3V to 14V
V_EEIN...................................................................0.3V to 14V
Input Voltages
PRSNT1#, PRSNT2#, SCL, RESETIN</a>,
OFF/ON...............................................................0.3V to 12V
5V_OUT, 5V_SENSE, 3V_IN,
3V_SENSE, 3V_OUT.....................................0.3V to (5V_IN+ 0.3V)
ADDRIN, PRECHARGE.........................................0.3V to 5V_IN
Output Voltages
TIMER, FAULT</a>, PWRGD</a>, SDA, RESETOUT</a>,
LED, DRIVE, GATE, 12V_OUT................................0.3V to 14V
V_EEOUT...............................................................14V to 0.3V
BE</a>...................................................0.3V to (5V_IN+ 0.3V)
Operating Temperature Range
LTC4240C...............................................0°C to 70°C
LTC4240I.............................................40°C to 85°C
Storage Temperature Range....................65°C to 150°C
Lead Temperature (Soldering, 10 sec)..................300°C


Description

The LTC4240 is a Hot Swap^TM controller that allows a board to be safely inserted and removed from a live CompactPCI bus slot. The LTC4240 has a built-in 2-wire I²C compatible interface to allow software control and monitoring of device function and power supply status. Two external N-channel transistors control the 3.3V and 5V supplies,while two internal switches control the 12V and 12V supplies. Electronic circuit breakers protect all four supplies against overcurrent faults. The PWRGD</a>output indicates when all of the supply voltages are within tolerance. The OFF/ON</a>pin is used to cycle the board power or reset the circuit breaker. The I²C interface of LTC4240 allows the user to turn the device off or on, set RESETOUT</a>, turn on the status LED driver and ignore 12V, 12V faults. It also allows the user to read the status of the FAULT</a>, RESETIN</a>, RESETOUT</a>,PWRGD</a>, PRSNT1# and PRSNT2# pins. Under a fault condition, the I²C interface can also be used to  determine which of the four supplies generated the fault. The LTC4240 is available in a 28-pin narrow SSOP package.