LTC4215-1_15 Datasheet, PDF (1/28 Pages) Linear Technology – 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 _{dI/dt Controlled Soft-Start}
n _{Circuit Breaker Timeout: 20μs (LTC4215-1) or}
420μs (LTC4215-3)
n _{Three General Purpose Outputs}
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}
APPLICATIONS
n _{Live Board Insertion}
n _{Electronic Circuit Breakers}
n _{Computers, Servers}
n _{Platform Management}
LTC4215-1/LTC4215-3
Hot Swap Controller with
I²C Compatible Monitoring
DESCRIPTION
The LTC^®4215-1/LTC4215-3 Hot Swap™ controllers allow
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 foldback current limit and
a soft-start pin that sets the dI/dt of the inrush current.
An I²C interface may configure the part to latch off or
automatically restart after the LTC4215-1/LTC4215-3
detect a current limit fault.
The controller has additional features to interrupt the host
when a fault has occurred, provide three general purpose
outputs, 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.
The LTC4215-1 has a 20μs circuit breaker filter for applica-
tions that require a fast fault response time. The LTC4215-3
has an extended 420μs circuit breaker filter for applications
where supply transients may exceed 20μs.
L, LT, LTC, LTM, Linear Technology and the Linear logo 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. Protected by U.S. Patent 7330065.
TYPICAL APPLICATION
12V Application With 5A Circuit Breaker
Start-Up Waveform
12V
SDA
SCL
GND
BACKPLANE PLUG-IN
CARD
0.1μF
3.4k
P6KE16A
34.8k
0.005Ω _FDC653N
V_OUT
+
12V
C_L 30.1k
10Ω
1.18k
3.57k
UV V_DD SENSE⁺ SENSE^– GATE SOURCE
OV
FB
SDAI
SDAO
SCL
ADR0
ADR1
LTC4215-1
GPIO1
GPIO2
GPIO3
ADIN
INTV_CC
ON TIMER SS
GND EN
POWERGOOD
RESET
OK LED
MEASURED
VOLTAGE
68nF
0.1μF
4215 TA01a
V_DD
10V/DIV
INRUSH
CURRENT
2.5A/DIV
V_OUT
10V/DIV
CONTACT
BOUNCE
V_GPIO1
10V/DIV
5k PULL-UP TO V_DD
C_L = 12000μF
40ms/DIV
42151 TA01b
421513fc
1