LTC4211_12 Datasheet, PDF (1/40 Pages) Linear Technology – Hot Swap Controller

LTC4211
Hot Swap Controller with
Multifunction Current Control
FEATURES
n _{Allows Safe Board Insertion and Removal}
from a Live Backplane
n _{Controls Supply Voltages from 2.5V to 16.5V}
n _{Programmable Soft-Start with Inrush Current}
Limiting, No External Gate Capacitor Required
n _{Faster Turn-Off Time Because No External Gate}
Capacitor is Required
n _{Dual Level Overcurrent Fault Protection}
n _{Programmable Response Time for Overcurrent}
Protection (MS)
n _{Programmable Overvoltage Protection (MS)}
n _{Automatic Retry or Latched Mode Operation (MS)}
n _{High Side Drive for an External N-Channel FET}
n _{User-Programmable Supply Voltage Power-Up Rate}
n _{FB Pin Monitors VOUT and Signals RESET}
n _{Glitch Filter Protects Against Spurious RESET Signal}
APPLICATIONS
n _{Electronic Circuit Breaker}
n _{Hot Board Insertion and Removal (Either On}
Backplane or On Removable Card)
n _{Industrial High Side Switch/Circuit Breaker}
DESCRIPTION
The LTC^®4211 is a Hot Swap™ controller that allows a board
to be safely inserted and removed from a live backplane.
An internal high side switch driver controls the gate of an
external N-channel MOSFET for supply voltages ranging
from 2.5V to 16.5V. The LTC4211 provides soft-start and
inrush current limiting during the start-up period which
has a programmable duration.
Two on-chip current limit comparators provide dual level
overcurrent circuit breaker protection. The slow com-
parator trips at V_CC – 50mV and activates in 20μs (or is
programmed by an external filter capacitor, MS only).
The fast comparator trips at V_CC – 150mV and typically
responds in 300ns.
The FB pin monitors the output supply voltage and signals
the RESET output pin. The ON pin signal turns the chip on
and off and can also be used for the reset function. The
MS package has FAULT and FILTER pins to provide addi-
tional functions like fault indication, autoretry or latch-off
modes, programmable current limit response time and
programmable overvoltage protection using an external
Zener diode clamp.
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.
TYPICAL APPLICATION
Single Channel 5V Hot Swap Controller
BACKPLANE PCB EDGE
CONNECTOR CONNECTOR
(FEMALE) (MALE)
V_CC
LONG
5V
R_X
Z1* ^10Ω
C_X
100nF
R_SENSE
0.007Ω
M1
Si4410DY
8
7
6
+
C_LOAD
R3
R5
V_OUT
5V
5A
V_CC SENSE
GATE
36k
5
10k
R1
FB
SHORT ^20k
2
ON
R2
10k
LTC4211
R4
15k
RESET ¹
μP
LOGIC
RESET
TIMER
GND
PCB CONNECTION SENSE
3 _CTIMER 4
LONG
10nF
GND
Z1 = 1SMA10A OR SMAJ10A
* OPTIONAL
GND
4211 TA01A
Power-Up Sequence
NO C_LOAD
V_GATE
5V/DIV
V_RESET
5V/DIV
V_ON
1V/DIV
V_TIMER
1V/DIV
2.5ms/DIV
4211 TA01b
4211fb
1