LTC4225-2_15 Datasheet, PDF (1/24 Pages) Linear Technology – Dual Ideal Diode and Hot Swap Controller

Features
n _{Power Path and Inrush Current Control for}
Redundant Supplies
n _{Low Loss Replacement for Power Schottky Diodes}
n _{Allows Safe Hot Swapping from a Live Backplane}
n _{2.9V to 18V Operating Range}
n _{Controls N-Channel MOSFETs}
n _{Limits Peak Fault Current in ≤1µs}
n _{0.5µs Turn-On and Reverse Turn-Off Time}
n _{Adjustable Current Limit with Circuit Breaker}
n _{Smooth Switchover without Oscillation}
n _{Adjustable Current Limit Fault Delay}
n _{Fault and Power Status Output}
n _{LTC4225-1: Latch Off After Fault}
n _{LTC4225-2: Automatic Retry After Fault}
n _{24-Lead 4mm × 5mm QFN and SSOP Packages}
Applications
n _{Redundant Power Supplies}
n _{Supply Holdup}
n _{MicroTCA Systems and Servers}
n _{Telecom Networks}
n _{Power Prioritizer}
LTC4225-1/LTC4225-2
Dual Ideal Diode and
Hot Swap Controller
Description
The LTC^®4225 offers ideal diode and Hot Swap™ functions
for two power rails by controlling external series connected
N-channel MOSFETs. MOSFETs acting as ideal diodes
replace two high power Schottky diodes and the associ-
ated heat sinks, saving power and board area. Hot Swap
control MOSFETs allow boards to be safely inserted and
removed from a live backplane by limiting inrush current.
The supply output is also protected against short-circuit
faults with a fast acting current limit and internal timed
circuit breaker.
The LTC4225 regulates the forward voltage drop across
the back-to-back MOSFETs to ensure smooth current
transfer from one supply to the other without oscillation.
The ideal diodes turn on quickly to reduce the load voltage
droop during supply switch-over. If the input supply fails
or is shorted, a fast turn-off minimizes reverse-current
transients.
The LTC4225 allows independent on/off control, and reports
fault and power good status for the supply. The LTC4225-1
features a latch-off circuit breaker, while the LTC4225-2
provides automatic retry after a fault.
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.
Typical Application
µTCA Application
0.004Ω Si7336ADP Si7336ADP
12V
0.1µF
PLUG-IN
CARD 1
12V
7.6A
137k
CPO1
IN1 SENSE1 DGATE1 HGATE1 OUT1
ON1
FAULT1
20k
INTV_CC
0.1µF
GND
LTC4225
PWRGD1
EN1
TMR1
TMR2
47nF
47nF
PLUG-IN
CARD 2
20k
137k
12V
ON2
CPO2
IN2
0.1µF
SENSE2 DGATE2
EN2
PWRGD2
FAULT2
HGATE2 OUT2
0.004Ω Si7336ADP Si7336ADP
BACKPLANE
12V
7.6A
422512 TA01a
Power Dissipation vs Load Current
3.0
2.5
2.0
DIODE
(SBG1025L)
1.5
POWER SAVED
1.0
0.5
0
0
MOSFET
(Si7336ADP)
2
4
6
LOAD CURRENT (A)
8
422512 TA01
422512f
1