Hot Swap Controller with
I2C Compatible Monitoring
n Allows Safe Insertion into Live Backplane
n 8-Bit ADC Monitors Current and Voltage
n I2C/SMBus Interface
n Wide Operating Voltage Range: 2.9V to 15V
n 20μs (LTC4215) or 420μs (LTC4215-2) Circuit
n dI/dt Controlled Soft-Start
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
n LTC4215 also available in 16-Lead Narrow SSOP
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.
Protected by U.S. Patent including 7330065.
The LTC®4215/LTC4215-2 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 detects a current
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.
The LTC4215 has a 20μs circuit breaker ﬁlter for applica-
tions that require a fast fault response time and it defaults
to latchoff after an overcurrent fault. The LTC4215-2 has
an extended 420μs circuit breaker ﬁlter for applications
where supply transients may exceed 20μs and it defaults
to restart automatically after an overcurrent fault.
12V Application with 5A Circuit Breaker
UV VDD SENSE+ SENSE– GATE SOURCE
ON TIMER SS
CL = 12000μF