Datasheet LTC3728 (Analog Devices) - 9

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