LTC4228-1 Datasheet, PDF (1/24 Pages) Linear Technology – Dual Ideal Diode and Hot Swap Controller

Features
n _{Power Path and Inrush Current Control for}
Redundant Supplies
n _{Low Loss Replacement for Power Schottky Diodes}
n _{Protects Output Voltage from Input Brownouts}
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 _{Adjustable Current Limit with Circuit Breaker}
n _{Adjustable Current Limit Fault Delay}
n _{Smooth Switchover without Oscillation}
n _{0.5µs Ideal Diode Turn-On and Turn-Off Time}
n _{Status, Fault and Power Good Outputs}
n _{LTC4228-1: Latch Off After Fault}
n _{LTC4228-2: Automatic Retry After Fault}
n _{28-Lead 4mm × 5mm QFN and SSOP Packages}
Applications
n _{Redundant Power Supplies}
n _{MicroTCA Systems and Servers}
n _{Telecom Networks}
n _{Power Prioritizer}
LTC4228-1/LTC4228-2
Dual Ideal Diode and
Hot Swap Controller
Description
The LTC^®4228 offers ideal diode and Hot Swap™ functions
for two power rails by controlling two external N-channel
MOSFETs in each rail. MOSFETs acting as ideal diodes re-
place two high power Schottky diodes and the associated
heat sinks, saving power and board area. Hot Swap control
MOSFETs allow boards 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 LTC4228 regulates the forward voltage drop across
the external MOSFETs and sense resistor 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 switch-over. If the
input supply fails or is shorted, a fast turn-off minimizes
reverse-current transients.
The LTC4228 allows independent on/off control, and reports
fault and power good status for the supply. The LTC4228
improves on the LTC4225 by recovering more quickly from
input brownouts to preserve the output voltage.
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.
Typical Application
µTCA Application
Si7336ADP
0.004Ω
Si7336ADP
12V
0.1µF
PLUG-IN
CARD 1
12V
7.6A
CPO1
IN1 DGATE1 SENSE1⁺ SENSE1^– HGATE1 OUT1
137k
20k
0.1µF
ON1
INTV_CC
GND
LTC4228
STATUS1
FAULT1
PWRGD1
EN1
47nF
TMR1
47nF
TMR2
20k
EN2
PWRGD2
ON2
FAULT2
STATUS2
137k
CPO2
IN2 DGATE2 SENSE2⁺ SENSE2^– HGATE2 OUT2
PLUG-IN
CARD 2
0.1µF
12V
Si7336ADP
0.004Ω
Si7336ADP
BACKPLANE
12V
7.6A
422812 TA01a
Smooth Supply Switchover
IN1
1V/DIV
IN2
1V/DIV
I_IN1
2A/DIV
I_IN2
2A/DIV
200ms/DIV
422512 TA01b
422812f
1