LT8350RVPBF datasheet(9/24 Pages) AD

9 / 24 page

LT8350

Rev. 0

For more information www.analog.com

PIN FUNCTIONS

LOADTG (Pin 22): High Side PMOS Load Switch Top Gate

Drive. The LOADTG pin produces a buffered and inverted

version of the LOADEN input signal and drives an external

high side PMOS load switch with a voltage swing from

the higher voltage between (VOUT−5V) and 1.2V to VOUT.

Leave this pin open if not used.

VOUT (Pin 24, 25): Power Output. The VOUT pins connect

to the power output of the converter, and also serve as

the positive rail for the LOADTG drive. Bypass this pin to

ground with a ceramic capacitor. The bypass capacitor

should be placed as close to the chip as possible with

vias directly down to the ground plane.

SW2 (Pin 27, 28): Boost Side Switch Node. The SW2 pins

connect to the internal power switches, and swing from

ground to a diode voltage above VOUT. Do not force any

voltage on these pins.

BST2 (Pin 29): Boost Side Bootstrap Floating Driver

Supply. The BST2 pin connects to an integrated bootstrap

diode from the INTVCC pin and supplies the boost side top

power switch gate driver. Place a 100nF bypass capacitor

to SW2 close to the package.

BST1 (Pin 30): Buck Side Bootstrap Floating Driver

Supply. The BST1 pin connects to an integrated bootstrap

diode from the INTVCC pin and supplies the buck side top

power switch gate driver. Place a 100nF bypass capacitor

to SW1 close to the package.

SW1 (Pin 31, 32): Buck Side Switch Node. The SW1 pins

connect to the internal power switches, and swing from a

diode voltage drop below ground up to VIN. Do not force

any voltage on these pins.

GND (Exposed Pad Pins 33, 34, 35, 36): Ground. Solder

the exposed pads directly to the ground plane.

Corner Pins: These pins are for mechanical support only

and can be tied anywhere on the PCB.

22nF capacitor is recommended on this pin. Any UVLO or

thermal shutdown immediately pulls SS pin to ground and

stops switching. Using a single resistor from SS to VREF,

the LT8350 can be set in three different fault modes dur-

ing output short-circuit fault condition: hiccup (no resis-

tor), latch-off (499k), and keep-running (100k). See more

details in the Applications Information section.

RT (Pin 18): Switching Frequency Setting. Connect a

resistor from this pin to ground to set the internal oscil-

lator frequency from 200kHz to 2MHz.

SYNC/MODE (Pin 19): External Switching Frequency

Synchronization and Operation Mode Selection. This

pin allows five selectable modes for optimization of

performance:

1. External Clock: For external frequency synchronization

and force continuous mode at light load.

2. INTVCC: For spread spectrum frequency modulation

and force continuous mode at light load.

3. VREF: For spread spectrum frequency modulation and

pulse-skipping mode at light load.

4. Float: For internal oscillator frequency and force con-

tinuous mode at light load.

5. GND: For internal oscillator frequency and pulse-skip-

ping mode at light load.

CLKOUT (Pin 20): Clock output. The CLKOUT pin provides

a 50% duty cycle square wave with 180 degrees out of

phase with the system clock. This allows synchronization

with other regulators. Float this pin if the CLKOUT func-

tion is not used.

EXTVCC (Pin 21): Second Input Supply for Powering

INTVCC. The part intelligently chooses either VIN or EXTVCC

for INTVCC LDO to improve efficiency. See EXTVCC con-

nection in the Applications Information section. Tie this

pin to GND if not used.

LT8350RVPBF датащи(PDF) 9 Page - Analog Devices

LT8350RVPBF датащи(HTML) 9 Page - Analog Devices

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

датащи скачать

ссылки URL