LTC3728_15 Datasheet, PDF (9/36 Pages) Linear Technology – Dual, 550kHz, 2-Phase Synchronous Step-Down Switching Regulator

LTC3728
PIN FUNCTIONS
INTV_CC (Pin 21/Pin 20): Output of the Internal 5V Linear
Low Dropout Regulator and the EXTV_CC Switch. The driver
and control circuits are powered from this voltage source.
Must be decoupled to power ground with a minimum of
4.7μF tantalum or other low ESR capacitor.
EXTV_CC (Pin 22/Pin 21): External Power Input to an
Internal Switch Connected to INTV_CC. This switch closes
and supplies V_CC power, bypassing the internal low drop-
out regulator, whenever EXTV_CC is higher than 4.7V. See
EXTV_CC connection in Applications section. Do not exceed
7V on this pin.
BG1, BG2 (Pins 23, 19/Pins 22, 18): High Current Gate
Drives for Bottom (Synchronous) N-Channel MOSFETs.
Voltage swing at these pins is from ground to INTV_CC.
V_IN (Pin 24/Pin 23): Main Supply Pin. A bypass capaci-
tor should be tied between this pin and the signal ground
pin.
BOOST1, BOOST2 (Pins 25, 18/Pins 24, 17): Bootstrapped
Supplies to the Topside Floating Drivers. Capacitors
are connected between the boost and switch pins and
Schottky diodes are tied between the boost and INTV_CC
pins. Voltage swing at the boost pins is from INTV_CC to
(V_IN + INTV_CC).
SW1, SW2 (Pins 26, 17/Pins 25, 15): Switch Node
Connections to Inductors. Voltage swing at these pins
is from a Schottky diode (external) voltage drop below
ground to V_IN.
TG1, TG2 (Pins 27, 16/Pins 26, 14): High Current Gate
Drives for Top N-Channel MOSFETs. These are the out-
puts of floating drivers with a voltage swing equal to
INTV_CC – 0.5V superimposed on the switch node voltage
SW.
PGOOD (Pin 28/Pin 27): Open-Drain Logic Output. PGOOD
is pulled to ground when the voltage on either V_OSENSE
pin is not within ±7.5% of its set point.
Exposed Pad (Pin 33) SGND: The Exposed Pad must be
soldered to PCB ground for electrical contact and rated
thermal performance.
3728fg
9