LTC4354
Negative Voltage
Diode-OR Controller
and Monitor
Fea T Descrip T
n
Controls N-Channel MOSFETs The LTC 4354 is a negative voltage diode-OR controller
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Replaces Power Schottky Diodes that drives two external N-channel MOSFETs. It replaces
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Less Than 1s Turn-off Time Limits Peak two Schottky diodes and the associated heat sink, saving
Fault Current power and area. The power dissipation is greatly reduced
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80V Operation by using N-channel MOSFETs as the pass transistors.
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Smooth Switchover without Oscillation Power sources can easily be ORed together to increase
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No Reverse DC Current total system power and reliability.
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Fault Output
When first powered up, the MOSFET body diode conducts
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Selectable Fault Thresholds
the load current until the pass transistor is turned on.
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Available in 8-Lead (3mm 2mm) DFN and
The LTC4354 servos the voltage drop across the pass
8-Lead SO Packages
transistors to ensure smooth transfer of current from one
transistor to the other without oscillation.
a T
The MOSFETs are turned off in less than 1s whenever
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AdvancedTCA Systems
the corresponding power source fails or is shorted. Fast
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48V Distributed Power Systems
turn-off prevents the reverse current from reaching a level
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Computer Systems/Servers
that could damage the pass transistors.
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Telecom Infrastructure
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A fault detection circuit with an open-drain output capable
Optical Networks
of driving an LED or opto-coupler indicates either MOSFET
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and
Hot Swap, PowerPath and ThinSOT are trademarks of Linear Technology Corporation. All other
short, MOSFET open or supply failed.
trademarks are the property of their respective owners.
Typical a T
48V Diode-OR Power Dissipation vs Load Current
48V_RTN 6
12k
5
33k DIODE (MBR10100)
V
4
CC
POWER
LOAD
LTC4354 FAULT 3
SAVED
V
SS 2
DA DB GA GB
LED
2k 2k
1F
1
FET (IRF3710)
V = 48V
A
4354 TA01
IRF3710
0
0 4 6 8 10
2
V = 48V
B
CURRENT (A)
IRF3710
4354 TA01b
4354fc
1
POWER DISSIPATION (W)
ion pplica
ions pplica
ion uresLTC4354
a T e Maxi Mu M r a T (Note 1)
I (100s duration) ...............................................50mA Operating Temperature Range
CC
Output Voltages LTC4354C ................................................ 0C to 70C
GA, GB .........................................0.3V to V + 0.3V LTC4354I .............................................40C to 85C
CC
FAULT ...................................................... 0.3V to 7V Storage Temperature Range .................. 65C to 150C
Input Voltages Lead Temperature (Soldering, 10 sec) ...................300C
DA, DB ................................................... 0.3V to 80V
Input Current
DA, DB Current ................................... 1mA to 20mA
p c F T
TOP VIEW TOP VIEW
DA 1 8 DB
DA 1 8 DB
V 2 7 FAULT
SS
V 2 7 FAULT
SS
9
V 3 6 GB
CC
V 3 6 GB
CC
GA 4 5 V
SS
GA 4 5 V
SS
S8 PACKAGE
8-LEAD PLASTIC SO
DDB PACKAGE
8-LEAD (3mm 2mm) PLASTIC DFN
T = 125C, = 150C/W
JMAX JA
T = 125C, = 76C/W
JMAX JA
EXPOSED PAD (PIN 9) IS V , CONNECTION TO PCB OPTIONAL
SS
o r D i n F Ma T
Lead Free Finish
TAPE AND REEL (MINI) TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE
LTC4354CDDB#TRMPBF LTC4354CDDB#TRPBF LBBK 8-Lead (3mm 2mm) Plastic DFN 0C to 70C
LTC4354IDDB#TRMPBF LTC4354IDDB#TRPBF LBMB 8-Lead (3mm 2mm) Plastic DFN 40C to 85C
TRM = 500 pieces. *Temperature grades are identified by a label on the shipping container.
LEAD FREE FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE
LTC4354CS8#PBF LTC4354CS8#TRPBF 4354 8-Lead Plastic SO 0C to 70C
LTC4354IS8#PBF LTC4354IS8#TRPBF 4354I 8-Lead Plastic SO 40C to 85C
Consult LTC Marketing for parts specified with wider operating temperature ranges.
Consult LTC Marketing for information on nonstandard lead based finish parts.
For more information on lead free part marking, go to: