LTC4223-2 Linear Technology, LTC4223-2 Datasheet - Page 7

• Manufacturer Part Number: LTC4223-2
• Description: Dual Supply Hot Swap Controller
• Manufacturer: Linear Technology

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PIN FUNCTIONS
12V
pin to the output of the current sense resistor. The electronic
circuit breaker trips if the voltage across the sense resistor
exceeds 50mV for more than a fault fi lter delay.
12V
disables the 12V supply until the input at 12V
9.7V.
12IMON (Pin 3): 12V Current Sense Monitoring Output.
This pin monitors the sense voltage between 12V
12V
the sense voltage is 33.
12ON (Pin 4): 12V Supply On Control Digital Input. A ris-
ing edge turns on the external N-channel MOSFET if ⎯ E ⎯ N
is pulled low and a falling edge turns it off. A high-to-low
transition on this pin will clear the 12V supply faults.
AUXIN (Pin 5): Auxiliary Supply Input. An internal 0.3Ω
switch is connected between AUXIN and AUXOUT pins.
Undervoltage lockout holds the switch off until the input
at AUXIN exceeds 2.5V.
V
to the device’s internal circuitry and operates from 2.7V to
6V. Undervoltage lockout circuit disables the device until
the input at V
AUXON (Pin 7): Auxiliary Supply On Control Digital Input.
A rising edge turns on the internal switch if ⎯ E ⎯ N is pulled
low and a falling edge turns it off. A high-to-low transi-
tion on both this pin and 12ON pin will clear the auxiliary
supply faults.
GND (Pin 8): Device Ground.
TIMER (Pin 9): Timer Capacitor Terminal. Connect a
capacitor between this pin and ground to set a 741ms/μF
duration for initial timing cycle, 123ms/μF for AUX current
limit during power-up and 6ms/μF duration for 12V current
limit before the external MOSFET is turned off.
⎯ E ⎯ N (Pin 10): Enable Input Intended for Card Presence
Detect. Ground this pin to enable the external N-channel
MOSFET and internal switch to turn on. If this pin is pulled
high, the switches are not allowed to turn on. An internal
100k resistor pulls up this pin. A high-to-low transition
will clear faults.
CC
SENSE
IN
SENSE
(Pin 6): Bias Supply Input. This pin provides power
(Pin 2): 12V Supply Input. Undervoltage lockout
. The gain ratio between this pin’s voltage and
(Pin 1): 12V Current Sense Input. Connect this
CC
exceeds 2.45V. Bypass with 330nF.
IN
exceeds
IN
and
⎯ A ⎯ U ⎯ X ⎯ P ⎯ G ⎯ O ⎯ O ⎯ D (Pin 11): Auxiliary Supply Power Status
Output. Open drain output that is normally pulled high
by an internal 10μA current source or an external pull-up
resistor to V
exceeds the power-good threshold of 2.901V.
AUXOUT (Pin 12): Auxiliary Supply Output. This pin is
the output from the internal switch connected between
AUXIN and AUXOUT pins. It signals ⎯ A ⎯ U ⎯ X ⎯ P ⎯ G ⎯ O ⎯ O ⎯ D low when
it exceeds 2.901V. A 750Ω active pull-down discharges
AUXOUT to ground when the internal switch is turned
off.
⎯ F ⎯ A ⎯ U ⎯ L ⎯ T (Pin 13): Auxiliary and 12V Supply Fault Status
Output. Open drain output that is normally pulled high by an
internal 10μA current source or an external pull-up resistor
to V
to an overcurrent fault on auxiliary or 12V supply.
⎯ 1 ⎯ 2 ⎯ P ⎯ G ⎯ O ⎯ O ⎯ D (Pin 14): 12V Supply Power Status Output.
Open drain output that is normally pulled high by an in-
ternal 10μA current source or an external pull-up resistor
to V
the power-good threshold of 10.36V.
12V
Input. Connect this pin to the source of the external N-
channel MOSFET for gate drive return. This pin signals
⎯ 1 ⎯ 2 ⎯ P ⎯ G ⎯ O ⎯ O ⎯ D low when it exceeds 10.36V. When the external
MOSFET is turned off, 12V
through a 800Ω active pull-down.
12V
Channel MOSFET. An internal 10μA current source charges
the gate of the external N-channel MOSFET. An internal
clamp limits the gate voltage to 6.2V above 12V
resistor and capacitor network from this pin to ground
sets the turn-on rate and compensates the active current
limit. During turn-off, a 1mA pull-down current discharges
12V
lockout, a 160mA pull-down current between 12V
12V
Exposed Pad (Pin 17, DHD Package): Exposed pad may
be left open or connected to device ground.
CC
CC
OUT
GATE
GATE
OUT
. It pulls low when the circuit breaker is tripped due
. It pulls low when the 12V
(Pin 15): 12V Gate Drive Return and Power-Good
is activated.
(Pin 16): Gate Drive for 12V Supply External N-
to ground. During short circuit or undervoltage
CC
LTC4223-1/LTC4223-2
. It pulls low when the AUXOUT pin voltage
OUT
is discharged to ground
OUT
pin voltage exceeds
GATE
OUT
422312f
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and
. A