LTC4215_15 Datasheet, PDF (1/28 Pages) Linear Technology – Hot Swap Controller with I2C Compatible Monitoring

LTC4215/LTC4215-2
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 _{20μs (LTC4215) or 420μs (LTC4215-2) Circuit}
Breaker Timeout
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}
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.
Protected by U.S. Patent including 7330065.
DESCRIPTION
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
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.
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.
TYPICAL APPLICATION
12V Application with 5A Circuit Breaker
12V
0.005Ω _FDC653N
+
V_OUT
12V
34.8k
0.1μF
C_{L 30.1k}
10Ω
SDA
SCL
ALERT
GND
BACKPLANE PLUG-IN
CARD
1.18k
P6KE16A
3.4k
INTV_CC
UV V_DD SENSE⁺ SENSE^– GATE SOURCE
OV
FB
SDAO
SDAI
SCL
ALERT
LTC4215UFD
EN
ADIN
INTV_CC
ON TIMER SS
GPIO
GND
68nF
0.1μF
3.57k
INTV_CC
24k
4215 TA01a
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
42151 TA01b
4215fe
1