LTC4353
Dual Low Voltage
Ideal Diode Controller
Features
Description
Low Loss Replacement for Power Diodes
n Controls N-Channel MOSFETs
n 0V to 18V Supply ORing or Holdup
n 1µs Gate Turn-On and Turn-Off Time
n Enable Inputs
n MOSFET On-Status Outputs
n 16-Lead MSOP and DFN (4mm × 3mm) Packages
The LTC®4353 controls external N-channel MOSFETs to
implement an ideal diode function. It replaces two high
power Schottky diodes and their associated heat sinks,
saving power and board area. The ideal diode function
permits low loss power supply ORing and supply holdup
applications.
n
The LTC4353 regulates the forward-voltage drop across
the MOSFET to ensure smooth current transfer in diode-OR
applications. A fast turn-on reduces the load voltage
droop during supply switchover. If the input supply fails
or is shorted, a fast turn-off minimizes reverse-current
transients.
Applications
n
n
n
n
Redundant Power Supplies
Supply Holdup
High Availability Systems and Servers
Telecom and Network Infrastructure
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
trademarks are the property of their respective owners. Protected by U.S. Patents, including
7920013 and 8022679.
The controller operates with supplies from 2.9V to 18V. If
both supplies are below 2.9V, an external supply is needed
at the VCC pin. Enable inputs can be used to turn off the
MOSFET and put the controller in a low current state.
Status outputs indicate whether the MOSFETs are on or off.
Typical Application
2.9V to 18V, 10A Ideal Diode-OR
Output Maintained with Failing Input Supply
Si4126DY
2.9V TO 18V
56nF*
VIN1
EN1
0.1µF
VIN1
VCC
GATE1
LTC4353
OUT1
ONST1
ONST2
GND
MOSFET
ON-STATUS
OUTPUTS
VOUT
10A
VOLTAGE 2V/DIV
CPO1
VIN2
VOUT
EN2
CPO2
VIN2
GATE2
OUT2
VIN1 = 5.2V
VIN2 = 5V
IL = 8A
CL = 100µF
56nF*
2.9V TO 18V
Si4126DY
4353 TA01a
5µs/DIV
4353 TA01b
*OPTIONAL FOR FAST TURN-ON
4353f
1
