LTC4228-1/LTC4228-2
Dual Ideal Diode and
Hot Swap Controller
Fea T Descrip T
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The LTC 4228 offers ideal diode and Hot Swap functions
Power Path and Inrush Current Control for
for two power rails by controlling two external N-channel
Redundant Supplies
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MOSFETs in each rail. MOSFETs acting as ideal diodes re-
Low Loss Replacement for Power Schottky Diodes
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place two high power Schottky diodes and the associated
Protects Output Voltage from Input Brownouts
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heat sinks, saving power and board area. Hot Swap control
Allows Safe Hot Swapping from a Live Backplane
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MOSFETs allow boards to be safely inserted and removed
2.9V to 18V Operating Range
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from a live backplane by limiting inrush current. The supply
Controls N-Channel MOSFETs
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output is also protected against short-circuit faults with a
Limits Peak Fault Current in 1s
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fast acting current limit and internal timed circuit breaker.
Adjustable Current Limit with Circuit Breaker
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Adjustable Current Limit Fault Delay
The LTC4228 regulates the forward voltage drop across
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Smooth Switchover without Oscillation
the external MOSFETs and sense resistor to ensure smooth
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0.5s Ideal Diode Turn-On and Turn-Off Time
current transfer from one supply to the other without
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Status, Fault and Power Good Outputs
oscillation. The ideal diodes turn on quickly to reduce
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LTC4228-1: Latch Off After Fault
the load voltage droop during supply switch-over. If the
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LTC4228-2: Automatic Retry After Fault
input supply fails or is shorted, a fast turn-off minimizes
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28-Lead 4mm 5mm QFN and SSOP Packages
reverse-current transients.
The LTC4228 allows independent on/off control, and reports
a T
fault and power good status for the supply. The LTC4228
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Redundant Power Supplies
improves on the LTC4225 by recovering more quickly from
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MicroTCA Systems and Servers
input brownouts to preserve the output voltage.
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Telecom Networks
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
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Power Prioritizer
trademarks are the property of their respective owners.
Typical a T
TCA Application
PLUG-IN
CARD 1
Smooth Supply Switchover
Si7336ADP Si7336ADP
0.004
12V
12V
7.6A
0.1F
+
CPO1 IN1 DGATE1 SENSE1 SENSE1 HGATE1 OUT1
IN1
1V/DIV
STATUS1
FAULT1
137k
IN2
PWRGD1
ON1 1V/DIV
EN1
47nF
20k
TMR1
I
IN1
INTV
CC
LTC4228
2A/DIV
0.1F
PLUG-IN
47nF
TMR2
GND
CARD 2
EN2
20k
PWRGD2
I
IN2
ON2 FAULT2
2A/DIV
STATUS2
137k
+
CPO2 IN2 DGATE2 SENSE2 SENSE2 HGATE2 OUT2 422512 TA01b
200ms/DIV
0.1F
12V
12V
7.6A
Si7336ADP 0.004 Si7336ADP
BACKPLANE 422812 TA01a
422812f
1
ion pplica
ions pplica
ion uresLTC4228-1/LTC4228-2
a Te Maxi Mu M r a T (Notes 1, 2)
Supply Voltages HGATE1, HGATE2 (Note 4) ..................... 0.3V to 35V
IN1, IN2 .................................................. 0.3V to 24V OUT1, OUT2 ........................................... 0.3V to 24V
INTV ..................................................... 0.3V to 7V Average Currents
CC
Input Voltages FAULT1, FAULT2, PWRGD1, PWRGD2 ...................5mA
ON1, ON2, EN1, EN2............................... 0.3V to 24V STATUS1, STATUS2 ..............................................5mA
TMR1, TMR2 .........................0.3V to INTV + 0.3V INTV .................................................................1mA
CC CC
+ +
SENSE1 , SENSE2 ................................ 0.3V to 24V Operating Temperature Range
SENSE1 , SENSE2 ................................ 0.3V to 24V LTC4228C ................................................ 0C to 70C
Output Voltages LTC4228I .............................................40C to 85C
FAULT1, FAULT2, PWRGD1, PWRGD2 ..... 0.3V to 24V Storage Temperature Range .................. 65C to 150C
STATUS1, STATUS2 ................................ 0.3V to 24V Lead Temperature (Soldering, 10 sec)
CPO1, CPO2 (Note 3) ............................. 0.3V to 35V GN Package ......................................................300C
DGATE1, DGATE2 (Note 3) ..................... 0.3V to 35V
p in c F T
TOP VIEW
TOP VIEW
STATUS1 1 28 HGATE1
CPO1 2 27 OUT1
DGATE1 3 26 PWRGD1
28 27 26 25 24 23
SENSE1 4 25 FAULT1
SENSE1 1 22 FAULT1
+ +
SENSE1 2 21 ON1 SENSE1 5 24 ON1
IN1 3 20 EN1
IN1 6 23 EN1
INTV 4 19
TMR1
CC INTV 7 22 TMR1
CC
29
GND
5 18 TMR2
GND 8 21 TMR2
IN2 6 17 EN2
IN2 9 20 EN2
+
SENSE2 7 16 ON2
+
SENSE2 10 19 ON2
SENSE2 8 15 FAULT2
SENSE2 11 18 FAULT2
9 10 11 12 13 14
DGATE2 12 17 PWRGD2
CPO2 13 16 OUT2
STATUS2 14 15 HGATE2
UFD PACKAGE
GN PACKAGE
28-LEAD (4mm 5mm) PLASTIC QFN
28-LEAD PLASTIC SSOP NARROW
T = 125C, = 43C/W (NOTE 5)
JMAX JA
T = 125C, = 80C/W
EXPOSED PAD (PIN 29) PCB GND CONNECTION OPTIONAL
JMAX JA
422812f
2
DGATE2
DGATE1
CPO2
CPO1
STATUS2 STATUS1
HGATE2 HGATE1
OUT2 OUT1
PWRGD2
PWRGD1
ion igura on
ings bsolu