LTC4222_15 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, LTM, Linear Technology and the Linear logo are registered trademarks and 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
Advanced Mezzanine Card Application
6mΩ _Si7336ADP
12V
12V
7.4A
34k
10.2k
0.1µF
1.02k
3.4k
ON
SDA
SCL
ALERT
NC
0.1µF
3.3V
0.1µF
3.4k
1.02k
6.55k
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
300mΩ ^Si1046R
3.57k ^10k
12PGOOD
1µF
68nF
AUXPGOOD
3.57k _10k
4.99k
4222 TA01a
BACKPLANE PLUG-IN
CARD
3.3V
150mA
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
4222fb
1