LTC4280 Datasheet, PDF (1/28 Pages) Linear Technology – Hot Swap Controller with I2C Compatible Monitoring

LTC4280
Hot Swap Controller with
I²C Compatible Monitoring
FEATURES
n _{Allows Safe Insertion into Live Backplane}
n _{8-Bit ADC Monitors Current and Voltage}
n _I²_{C/SMBus Interface}
n _{Wide Operating Voltage Range: 2.9V to 15V}
n _{Adjustable Overcurrent Filter Time}
n _{High Side Drive for External N-Channel MOSFET}
n _{No External Gate Capacitor Required}
n _{Input Overvoltage/Undervoltage Protection}
n _{Optional Latchoff or Auto-Retry After Faults}
n _{Alerts Host After Faults}
n _{Inrush Current Limit with Foldback}
n _{Available in 24-Pin 4mm × 5mm QFN Package}
APPLICATIONS
n _{Live Board Insertion}
n _{Electronic Circuit Breakers}
n _{Computers, Servers}
n _{Platform Management}
L, LT, LTC, LTM, Linear Technology, the Linear logo and Hot Swap are registered trademarks of
Linear Technology Corporation. All other trademarks are the property of their respective owners.
DESCRIPTION
The LTC^®4280 Hot Swap™ controller allows a board to be
safely inserted and removed from a live backplane. Using
an external N-channel pass transistor, board supply voltage
and inrush current are ramped up at an adjustable rate.
An I²C interface and onboard ADC allow for monitoring
of load current, voltage and fault status.
The device features adjustable analog foldback current
limit and a FILTER pin which configures the time spent in
overcurrent before declaring a fault. An I²C interface may
configure the part to latch off or automatically restart after
the LTC4280 detects a current limit fault.
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 either
automatically upon insertion or wait for an I²C command
to turn on.
TYPICAL APPLICATION
12V Application with 5A Circuit Breaker
12V
SDA
SCL
ALERT
GND
BACKPLANE PLUG-IN
CARD
34.8k
0.1μF
0.005Ω _FDC653N
+
V_OUT
12V
C_{L 30.1k}
10Ω
1.18k
P6KE16A
3.4k
INTV_CC
UV V_DD SENSE⁺ SENSE^– GATE SOURCE
OV
FB
SDAO
SDAI
SCL
ALERT
LTC4280
EN
ADIN
GPIO
INTV_{CC ON TIMER FILTER GND}
47nF
0.1μF
3.57k
INTV_CC
24k
4280 TA01
Start-Up Waveform
V_DD
10V/DIV
INRUSH
CURRENT
2.5A/DIV
V_OUT
10V/DIV
V_GPIO
(POWERGOOD)
10V/DIV
CONTACT
BOUNCE
C_L = 12000μF
50ms/DIV
4280 TA02
4280f
1