LTC4229_15 Datasheet, PDF (1/28 Pages) Linear Technology – Ideal Diode and Hot Swap Controller

Features
n _{Ideal Diode and Inrush Current Control for}
Redundant Supplies
n _{Low Loss Replacement for Power Schottky Diode}
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 Back-to-Back 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 _{Undervoltage and Overvoltage Protection}
n _{Status, Fault and Power Good Outputs}
n _{Pin Selectable Latch Off or Automatic Retry}
After Fault
n _{24-Lead 4mm × 5mm QFN and SSOP Packages}
Applications
n _{Redundant Power Supplies}
n _{Supply Holdup}
n _{High Availability Systems and Servers}
n _{Telecom and Network Infrastructure}
n _{Power Prioritizer}
LTC4229
Ideal Diode and
Hot Swap Controller
Description
The LTC^®4229 offers ideal diode and Hot Swap™ functions
for a power rail by controlling two external N-channel MOS-
FETs. The MOSFET acting as an ideal diode replaces a high
power Schottky diode and the associated heat sink, saving
power and board area. The Hot Swap MOSFET control al-
lows 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
foldback current limit and electronic circuit breaker.
The LTC4229 regulates the forward voltage drop across
the external MOSFET to ensure smooth current transfer
in diode-OR applications. The ideal diode turns on quickly
to reduce the load voltage droop during supply switcho-
ver. If the input supply fails or is shorted, a fast turn-off
minimizes reverse-current transients.
The LTC4229 provides adjustable start-up delay, under-
voltage and overvoltage protection, and reports fault and
power good status for the supply. It can be configured
for latch off or automatic retry after a fault.
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and Hot
Swap is a trademark of Linear Technology Corporation. All other trademarks are the property of
their respective owners.
Protected by U.S. Patents, including 7920013, 8022679.
Typical Application
Plug-In Supply Card Application
PLUG-IN
SUPPLY
DIODE FET
HOT SWAP FET
CARD
SiR818DP
0.0025Ω SiR818DP
12V
+
V_OUT
7.6A
680µF
0.1µF
10Ω
1k
10nF
CPO DSRC IN DGATE DSNS SENSE⁺ SENSE^– HGATE
OUT
15k
21.5k
FB
2k
UV
1.1k
LTC4229
OV
2k
DOFF GND DCFG INTV_CC RTMR DTMR FTMR
PWRGD
FAULT
DSTAT
DFLT
EN
0.1µF
0.1µF
BACKPLANE
4229 TA01a
IN
10V/DIV
OUT
10V/DIV
DGATE
20V/DIV
HGATE
20V/DIV
For more information www.linear.com/LTC4229
Diode FET Protects Output
Voltage from Input Brownout
50µs/DIV
4229 TA01b
4229f
1