LTC4222 Datasheet, PDF (1/32 Pages) Linear Technology – Dual Hot Swap Controller with I2C Compatible Monitoring

FEATURES
n _{Allows Safe Insertion Into a Live Backplane}
n _{10-Bit ADC Monitors Currents and Voltages}
n _I²_{C/SMBus Interface}
n _{Wide Operating Voltage Range: 2.9V to 29V}
n _{dI/dt Controlled Soft-Start}
n _{High Side Drive for External N-Channel MOSFETs}
n _{No External Gate Capacitors Required}
n _{Input Overvoltage/Undervoltage Protection}
n _{Optional Latchoff or Auto-Retry After Faults}
n _{Alert Host After Faults}
n _{Inrush Current Limit with Foldback}
n _{Available in 32-Pin (5mm × 5mm) QFN and 36-Pin}
SSOP Packages
APPLICATIONS
n _{Live Board Insertion}
n _{Electronic Circuit Breakers}
n _{Computers, Servers}
n _{Platform Management}
LTC4222
Dual Hot Swap Controller
with I²C Compatible
Monitoring
DESCRIPTION
The LTC^®4222 Hot Swap™ controller allows two power
paths to be safely inserted and removed from a live back-
plane. Using external N-channel pass transistors, board
supply voltages and inrush currents are ramped up at an
adjustable rate. An I²C interface and onboard ADC allows
for monitoring of current, voltage and fault status for
each channel.
The device features adjustable, analog, foldback current
limit circuits and a Soft-Start circuit that sets the dI/dt of
the inrush currents. An I²C interface may configure the
part to latch off or automatically restart after the LTC4222
detects a fault on either channel.
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.
L, LT, LTC and LTM 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. Patents including 7330065.
TYPICAL APPLICATION
12V
0.1μF
34k
1.02k
3.4k
ON
SDA
SCL
ALERT
NC
0.1μF
3.3V
0.1μF
3.4k
1.02k
6.55k
Advanced Mezzanine Card Application
6mΩ _Si7336ADP
10.2k
10Ω
UV1 V_DD1
OV1
ON
SDA
SCL
ALERT
CONFIG
ADR0
ADR1
ADR2
INTV_CC
GND
OV2
UV2 V_DD2
SENSE1^– GATE1 SOURCE1
FB1
GPIO1
EN1
ADIN1
TIMER
LTC4222
SS
ADIN2
EN2
GPIO2
FB2
SENSE2^– GATE2 SOURCE2
10Ω 10nF
3.57k ^10Ω
12PGOOD
1μF
68nF
AUXPGOOD
3.57k _10Ω
12V
7.4A
Start-Up Waveform with Sequencing
V_IN1/2
10V/DIV
V_OUT2
10V/DIV
CONTACT
BOUNCE
V_OUT1
10V/DIV
GPIO
PGOOD
10V/DIV
50ms/DIV
4222 TA01b
300mΩ ^Si1046R
4.99k
4222 TA01a
BACKPLANE PLUG-IN
CARD
3.3V
150mA
4222f
1