LTC4236

1

4236f

For more information www.linear.com/LTC4236

Typical applicaTion

FeaTures

DescripTion

Dual Ideal Diode-OR and

Single Hot Swap Controller

with Current Monitor

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

high power Schottky diodes and the associated heat sinks,

saving power and board area. A Hot Swap control MOSFET

allows a board to be safely inserted and removed from a

livebackplanebylimitinginrushcurrent.Thesupplyoutput

is also protected against short-circuit faults with a fast

acting foldback current limit and electronic circuit breaker.

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.

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.

applicaTions

n

Ideal Diode-OR and Inrush Current Control for

Redundant Supplies

n

Low Loss Replacement for Power Schottky Diodes

n

Enables Safe Board Insertion into a Live Backplane

n

2.9V to 18V Operating Range

n

Current Monitor Output

n

Controls N-Channel MOSFETs

n

Limits Peak Fault Current in ≤ 1µs

n

Adjustable Current Limit with Foldback

n

Adjustable Start-Up and Current Limit Fault Delay

n

0.5µs Ideal Diode Turn-On and Turn-Off Time

n

Smooth Switchover without Oscillation

n

Fault, Power Good and Diode Status Outputs

n

LTC4236-1: Latch Off After Fault

n

LTC4236-2: Automatic Retry After Fault

n

28-Pin 4mm x 5mm QFN Package

n

Redundant Power Supplies

n

High Availability Systems and Servers

n

Telecom and Network Infrastructure

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.

Ideal Diode-OR with Hot Swap Application

+

ADC

12V

12V

CPO1

GND

ON

13.7k

12V

7A

2k

D2OFF

IN1 DGATE1

DGATE2

LTC4236

4236 TA01a

SiR158DP

SiR158DP

0.003

HGATE OUT

CPO2

0.1µF

IN2

D2SRC

0.1µF

SiR158DP

EN

0.1µF

0.1µF

DTMR

0.1µF

FTMR

REG

0.1µF

FAULT

PWRGD

DSTAT1

DSTAT2

FB

15k

2k

IMON

Smooth Supply Switchover

200ms/DIV

IN1

1V/DIV

IN2

1V/DIV

IN2

IN1

2A/DIV

2A/DIV

4236 TA01b