LTC4236
Dual Ideal Diode-OR and
Single Hot Swap Controller
with Current Monitor
DescripTion
The LTC®4236 offers ideal diode-OR and Hot Swap func-
tions for two power rails by controlling external N-channel
MOSFETs. MOSFETs acting as ideal diodes replace two
highpowerSchottkydiodesandtheassociatedheatsinks,
savingpowerandboardarea.AHotSwapcontrolMOSFET
allows a board to be safely inserted and removed from a
livebackplanebylimitinginrushcurrent.Thesupplyoutput
is also protected against short-circuit faults with a fast
actingfoldbackcurrentlimitandelectroniccircuitbreaker.
FeaTures
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Ideal Diode-OR and Inrush Current Control for
Redundant Supplies
Low Loss Replacement for Power Schottky Diodes
Enables Safe Board Insertion into a Live Backplane
2.9V to 18V Operating Range
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Current Monitor Output
Controls N-Channel MOSFETs
Limits Peak Fault Current in ≤ 1µs
Adjustable Current Limit with Foldback
Adjustable Start-Up and Current Limit Fault Delay
0.5µs Ideal Diode Turn-On and Turn-Off Time
Smooth Switchover without Oscillation
Fault, Power Good and Diode Status Outputs
LTC4236-1: Latch Off After Fault
The LTC4236 regulates the forward voltage drop across
theidealdiodeMOSFETstoensuresmoothcurrenttransfer
from one supply to the other without oscillation. The ideal
diode MOSFETs turn on quickly to reduce the load voltage
droop during supply switchover. If the input supply fails
or is shorted, a fast turn-off minimizes reverse current
transients.
LTC4236-2: Automatic Retry After Fault
28-Pin 4mm x 5mm QFN Package
A current sense amplifier translates the voltage across the
senseresistortoagroundreferencedsignal.TheLTC4236
provides adjustable start-up delay, turn-on/-off control,
and reports fault and power good status for the supply.
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. All other trademarks are the property of their respective owners.
Protected by U.S. Patents, including 7920013, 8022679.
applicaTions
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Redundant Power Supplies
High Availability Systems and Servers
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Telecom and Network Infrastructure
Typical applicaTion
Ideal Diode-OR with Hot Swap Application
SiR158DP
Smooth Supply Switchover
12V
12V
IN2
0.1µF
SiR158DP
0.003Ω
SiR158DP
12V
7A
IN1
+
IN1
1V/DIV
0.1µF
0.1µF
C
LOAD
IN2
1V/DIV
+
+
–
13.7k
2k
CPO1 IN1 DGATE1 CPO2 D2SRC IN2 DGATE2
ON
REG SENSE CS
SENSE HGATE OUT
15k
2k
I
IN1
FB
2A/DIV
I
IN2
2A/DIV
LTC4236
FAULT
PWRGD
DSTAT1
DSTAT2
4236 TA01b
200ms/DIV
EN
IMON
FTMR
ADC
INTV
CC
0.1µF
GND
D2OFF
DTMR
0.1µF
0.1µF
4236 TA01a
4236f
1
For more information www.linear.com/LTC4236