LTC3789_15 Datasheet, PDF (10/30 Pages) Linear Technology – High Efficiency, Synchronous, 4-Switch Buck-Boost Controller

LTC3789
Pin Functions (SSOP/QFN)
INTV_CC (Pin 21/Pin 18): Output of the Internal Linear Low
Dropout Regulator. The driver and control circuits are
powered from this voltage source. Must be bypassed to
power ground with a minimum of 4.7µF tantalum, ceramic,
or other low ESR capacitor.
V_IN (Pin 22/Pin 19): Main Supply Pin. A bypass capacitor
should be tied between this pin and the power ground pin.
BG1, BG2 (Pins 23, 19/Pins 20, 16): High Current
Gate Drives for Bottom (Synchronous) N-Channel
MOSFETs. Voltage swing at these pins is from ground to
INTV_CC.
PGND (Pin 24/Pin 21): Driver Power Ground. Connects
to C_OUT and R_SENSE (–) terminal(s) of C_IN.
BOOST1, BOOST2 (Pins 25, 18/Pins 22, 15): Bootstrapped
Supplies to the Top Side Floating Drivers. Capacitors
are connected between the BOOST and SW pins and
Schottky diodes are tied between the BOOST and INTV_CC
pins. Voltage swing at the BOOST1 pin is from INTV_CC
to (V_IN + INTV_CC). Voltage swing at the BOOST2 pin is
from INTV_CC to (V_OUT + INTV_CC).
TG1, TG2 (Pins 26, 17/Pins 23, 14): High Current
Gate Drives for Top N-Channel MOSFETs. These are the
outputs of floating drivers with a voltage swing equal
to INTV_CC – 0.5V superimposed on the switch node
voltage SW.
SW1, SW2 (Pins 27, 16/Pins 24, 13): Switch Node
Connections to Inductors. Voltage swing at the SW1
pin is from a Schottky diode (external) voltage drop
below ground to V_IN. Voltage swing at the SW2 pin is
from a Schottky diode voltage drop below ground to
V_OUT.
PGOOD (Pin 28/Pin 25): Open-Drain Logic Output.
PGOOD is pulled to ground when the voltage on the V_FB
pin is not within ±10% of its regulation window, after the
internal 20µs power-bad mask timer expires.
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