LTC4229_15 Datasheet, PDF (8/28 Pages) Linear Technology – Ideal Diode and Hot Swap Controller

LTC4229
Pin Functions
HGATE: Hot Swap MOSFET Gate Drive Output. Connect
this pin to the gate of the external N-channel MOSFET for
Hot Swap control. An internal 10µA current source charges
the MOSFET gate. An internal clamp limits the gate voltage
to 12V above and a diode voltage below OUT. During an
undervoltage or overvoltage generated turn-off, a 2mA
pull-down discharges HGATE to ground. During an output
short or INTV_CC undervoltage lockout, a fast 200mA pull-
down discharges HGATE to OUT.
IN: Positive Supply Input. The 5V INTV_CC supply is gener-
ated from IN, SENSE⁺ and OUT via an internal diode-OR.
The voltage sensed at this pin is used to control DGATE.
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. An undervolt-
age lockout threshold of 2.2V will turn off both MOSFETs.
OUT: Hot Swap’s MOSFET Gate Drive Return. Connect
this pin to the output side of the external MOSFET. The
gate fast pull-down current returns through this pin when
HGATE is discharged.
OV: Overvoltage Comparator Input. Connect this pin to an
external resistive divider from IN or SENSE⁺ to monitor
the supply overvoltage condition. If the voltage at this pin
rises above 1.235V, an overvoltage fault is detected and
the Hot Swap MOSFET turns off. Tie to GND if unused.
PWRGD: Power Status Output. Output that pulls low when
the FB pin rises above 1.235V and the MOSFET gate drive
between HGATE and OUT exceeds 4.2V. Otherwise it is
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. Leave open if unused.
RTMR: Auto-Retry Timer Capacitor Terminal. Connect this
pin to INTV_CC for fault latch off. Leave open for auto-retry
with 0.1% duty cycle after a fault. Connect an external
capacitor to extend the Hot Swap MOSFET off time set
by the FTMR pin capacitor to less than 0.1% auto-retry
duty cycle after a fault.
SENSE⁺: Positive Current Sense Input. Connect this pin to
the 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.
SENSE^–: Negative Current Sense Input. Connect 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 25mV or less depending on the
voltage at the FB pin.
UV: Undervoltage Comparator Input. Connect this pin to
an external resistive divider from IN or SENSE⁺ to monitor
the supply undervoltage condition. If the voltage at this
pin falls below 1.155V, an undervoltage fault is detected
and the Hot Swap MOSFET turns off. Pulling the UV pin
below 0.6V resets the fault latch after an overcurrent fault.
Tie to INTV_CC if unused.
4229f
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