40V, High-Performance, Synchronous

Buck Controller

8 ______________________________________________________________________________________

Pin Description

PIN

NAME

FUNCTION

1

IN

Regulator Input. Connect to the input rail of the buck converter. Bypass IN to PGND with a 100nF

2

DRV.

3

PGOOD

Open-Drain Power-Good Output. Pull up PGOOD to an external power supply or output with an

external resistor.

4

EN

for always-on operation. EN can be used for power sequencing and as a UVLO adjustment input.

5

LIM

Current-Limit Input. Connect a resistor from LIM to GND to program the current-limit threshold from

6

COMP

Error-Amplifier Output. Connect compensation network from COMP to FB or from COMP to GND.

7

FB

Feedback Input (Inverting Input of Error Amplifier). Connect FB to a resistive divider between the

buck converter output and GND to adjust the output voltage from 0.6V up to 0.85 x IN.

8

RT

Oscillator-Timing Resistor Input. Connect a resistor from RT to GND to set the oscillator frequency

from 100kHz to 1MHz.

9

GND

Analog Ground. Connect PGND and AGND together at a single point.

10

PGND

Power Ground. Use PGND as a return path for the low-side MOSFET gate driver.

11

DRV

Gate-Driver Supply Voltage. DRV is internally connected to the low-side driver supply. Bypass DRV to

PGND with a 2.2FF minimum ceramic capacitor (see the Typical Application Circuits).

12

DL

Low-Side External MOSFET Gate-Driver Output. DL swings from DRV to PGND.

13

BST

Boost Flying Capacitor Connection. Internally connected to the high-side driver supply. Connect a

ceramic capacitor of at least 100nF between BST and LX and a diode between BST and DRV for

the high-side MOSFET gate-driver supply.

14

LX

Inductor Connection. Also serves as a return terminal for the high-side MOSFET driver current.

Connect LX to the switching side of the inductor.

15

DH

High-Side External MOSFET Gate-Driver Output. DH swings from BST to LX.

16

CSP

Current-Sense Positive Input. Connect to the drain of low-side MOSFET with Kelvin connection.

—

EP

Exposed Pad. EP is internally connected to ground. Connect EP to a large copper ground plane to

maximize thermal performance.