Datasheet

LTC4215-1/LTC4215-3
9
421513fc
OV: Overvoltage Comparator Input. Connect this pin to an
external resistive divider from V
DD
. If the voltage at this
pin rises above 1.235V, an overvoltage fault is detected
and the GATE turns off. Tie to GND if unused.
SCL: Serial Bus Clock Input. Data at the SDA pin is shifted
in or out on rising edges of SCL. This is a high impedance
pin that is generally driven by an open-collector output
from a master controller. An external pull-up resistor or
current source is required.
SDAO: Serial Bus Data Output. Open-drain output for
s en din g d at a b ac k to t he ma st er c on tr ol le r o r a ck no wl edg -
ing a write operation. Normally tied to SDAI to form the
SDA line. An external pull-up resistor or current source
is required.
SDAI: Serial Bus Data Input. A high impedance input for
shifting in address, command or data bits. Normally tied
to SDAO to form the SDA line.
SENSE
+
: Positive Current Sense Input. Connect this pin to
the input of the current sense resistor. Must be connected
to the same trace as V
DD
.
SENSE
–
: Negative Current Sense Input. Connect this
pin to the output of the current sense resistor. This pin
provides sense voltage feedback and monitoring for the
current limit, circuit breaker and ADC.
SOURCE: N-channel MOSFET Source and ADC Input.
Connect this pin to the source of the external N-channel
MOSFET switch for gate drive return. This pin also serves
as the ADC input to monitor output voltage. The pin pro-
vides a return for the gate pull-down circuit.
SS: Soft Start Input. Sets the inrush current slew rate at
start-up. Connect a 68nF capacitor to provide 5mV/ms as
the slew rate for the sense voltage in start-up. This cor-
responds to 1A/ms with a 5mΩ sense resistor. Note that
a large soft-start capacitor and a small TIMER capacitor
may result in a condition where the timer expires before
the inrush current has started. Allow an additional 10nF
of timer capacitance per 1nF of soft-start capacitor to
ensure proper start-up. Use 1nF minimum to ensure an
accurate inrush current.
TIMER: Start-Up Timer Input. Connect a capacitor be-
tween this pin and ground to set a 12.3ms/µF duration
for start-up, after which an overcurrent fault is logged if
the inrush is still current limited. The duration of the off
time is 600ms/µF when overcurrent auto retry is enabled,
resulting in a 1:50 duty cycle. An internal timer provides
a 100ms start-up time and 5 seconds auto-retry time if
this pin is tied to INTV
CC
. Allow an additional 10nF of
timer capacitance per 1nF of soft-start (SS) capacitor to
ensure proper start-up. The minimum value for the TIMER
capacitor is 10nF.
UV: Undervoltage Comparator Input. Connect this pin
to an external resistive divider from V
DD
. If the voltage
at this pin falls below 1.155V, an undervoltage fault is
detected and the GATE turns off. Pulling this pin below
0.4V resets all faults and allows the GATE to turn back
on. Tie to INTV
CC
if unused.
V
DD
: Supply Voltage Input. This pin has an undervoltage
lockout threshold of 2.84V and overvoltage lockout
threshold of 15.6V
PIN FUNCTIONS