LTC3812-5_15 Datasheet, PDF (9/34 Pages) Linear Technology – 60V Current Mode Synchronous Switching Regulator Controller

LTC3812-5
PIN FUNCTIONS
EXTV_CC (Pin 10): External Driver Supply Voltage. When
this voltage exceeds 4.2V, an internal switch connects
this pin to INTV_CC through an LDO and turns off the exter-
nal MOSFET connected to NDRV, so that controller and
gate drive are drawn from EXTV_CC.
INTV_CC (Pin 11): Main Supply and Driver Supply Pin. All
internal circuits and bottom gate output driver are powered
from this pin. INTV_CC should be bypassed to SGND and
PGND with a low ESR (X5R or better) 1μF capacitor in
close proximity to the LTC3812-5.
BG (Pin 12): Bottom Gate Drive. The BG pin drives the
gate of the bottom N-channel synchronous switch MOSFET.
This pin swings from PGND to INTV_CC.
PGND (Pin 13): Bottom Gate Return. This pin connects
to the source of the pull-down MOSFET in the BG driver
and is normally connected to ground.
SW (Pin 14): Switch Node Connection to Inductor and
Bootstrap Capacitor. Voltage swing at this pin is from a
Schottky diode (external) voltage drop below ground
to V_IN.
TG (Pin 15): Top Gate Drive. The TG pin drives the gate of
the top N-channel synchronous switch MOSFET. The TG
driver draws power from the BOOST pin and returns to the
SW pin, providing true floating drive to the top MOSFET.
BOOST (Pin 16): Top Gate Driver Supply. The BOOST pin
supplies power to the floating TG driver. BOOST should
be bypassed to SW with a low ESR (X5R or better) 0.1μF
capacitor. An additional fast recovery Schottky diode from
INTV_CC to the BOOST pin will create a complete floating
charge-pumped supply at BOOST.
GND (Exposed Pad Pin 17): Ground. The Exposed Pad
must be soldered to PCB ground.
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