Datasheet

LTC4228-1/LTC4228-2
7
422812f
pin FuncTions
INTV
CC
: Internal 5V Supply Decoupling Output. This pin
must have a 0.1µF or larger capacitor. An external load of
less than 500µA can be connected at this pin.
ON1, ON2: On Control Input. A rising edge above 1.235V
turns on the external Hot Swap MOSFET and a falling edge
below 1.155V turns it off. Connect this pin to an external
resistive divider from IN or SENSE
+
to monitor the supply
undervoltage condition. Pulling the ON pin below 0.6V
resets the electronic circuit breaker.
OUT1, OUT2: Output Voltage Sense and Hot Swap’s MOS-
FET Gate Drive Return. Connect this pin to the output side
of the external MOSFET. The voltage sensed at this pin is
used to control DGATE. The gate fast pull-down current
returns through this pin when HGATE is discharged.
PWRGD1, PWRGD2: Power Status Output. Open-drain
output that is normally pulled high by a 10µA current
source to a diode below INTV
CC
. It may be pulled above
INTV
CC
using an external pull-up. It pulls low when the
MOSFET gate drive between HGATE and OUT exceeds
the gate-to-source voltage of 4.2V. Leave open if unused.
SENSE1
+
, SENSE2
+
: Positive Current Sense Input. Connect
this pin to the output of the external ideal diode MOSFET
and input of the current sense resistor. The voltage sensed
at this pin is used for monitoring the current limit. This
pin has an undervoltage lockout threshold of 1.9V that
will turn off the Hot Swap MOSFET.
SENSE1
–
, SENSE2
–
: Negative Current Sense Input. Con-
nect this pin to the output of the current sense resistor.
The current limit circuit controls HGATE to limit the voltage
between SENSE
+
and SENSE
–
to 65mV. A circuit breaker
trips when the sense voltage exceeds 50mV for more than
a fault filter delay configured at the TMR pin.
STATUS1, STATUS2: Diode MOSFET Status Output.
Open-drain output that is normally pulled high by a 10µA
current source to a diode below INTV
CC
. It may be pulled
above INTV
CC
using an external pull-up. It pulls low when
the MOSFET gate drive between DGATE and IN exceeds
the gate-to-source voltage of 0.7V. Leave open if unused.
TMR1, TMR2: Timer Capacitor Terminal. Connect a capaci-
tor between this pin and ground to set a 12ms/µF duration
for current limit before the external Hot Swap MOSFET
is turned off. The duration of the off time is 617ms/µF,
resulting in a 2% duty cycle.