LTC4227_15 Datasheet, PDF (1/22 Pages) Linear Technology – Dual Ideal Diode and Single Hot Swap Controller

LTC4227
Dual Ideal Diode and
Single Hot Swap Controller
Features
n _{Power Path and Inrush Current Control for}
Redundant Supplies
n _{Low Loss Replacement for Power Schottky Diodes}
n _{Allows Safe Hot Swapping from a Live Backplane}
n _{2.9V to 18V Operating Range}
n _{Controls N-Channel MOSFETs}
n _{Limits Peak Fault Current in ≤1µs}
n _{0.5µs Ideal Diode Turn-On and Reverse Turn-Off Time}
n _{Adjustable Current Limit with Circuit Breaker}
n _{Smooth Switchover without Oscillation}
n _{Adjustable Current Limit Fault Delay}
n _{Fault and Power Status Output}
n _{20-Lead 4mm × 5mm QFN and 16-Lead SSOP Packages}
Applications
n _{Redundant Power Supplies and Supply Holdup}
n _{Computer Systems and Servers}
n _{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
trademarks are the property of their respective owners.
Description
The LTC^®4227 offers ideal diode-OR and Hot Swap™
functions 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 live backplane by limiting inrush current. The supply
output is also protected against short-circuit faults with a
fast acting current limit and internal timed circuit breaker.
The LTC4227 regulates the forward voltage drop across
the MOSFETs to ensure smooth current transfer from one
supply to the other without oscillation. The ideal diodes
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.
The LTC4227 allows turn-on/off control, and reports fault
and power good status for the supply.
PART
LTC4227-1
LTC4227-2
LTC4227-3
LTC4227-4
OVERCURRENT FAULT
LATCH OFF
RETRY
LATCH OFF
RETRY
START-UP DELAY
100ms
100ms
1.6ms
1.6ms
Typical Application
Diode-OR with Hot Swap Application
SiR462DP
12V
0.1µF
12V
SiR462DP 0.006Ω Si7336ADP
12V
+
7.6A
0.1µF
100µF
137k _{CPO1 IN1 DGATE1 CPO2}
ON
20k
IN2 DGATE2 SENSE⁺ SENSE^– HGATE OUT
LTC4227
FAULT
PWRGD
EN
INTV_CC
D2ON
GND
BACKPLANE CARD
CONNECTOR CONNECTOR
0.1µF
TMR
0.1µF
4227 TA01a
For more information www.linear.com/LTC4227
IN1
1V/DIV
IN2
1V/DIV
I_IN1
2A/DIV
I_IN2
2A/DIV
Smooth Supply Switchover
200ns/DIV
4227 TA01b
422712fa
1