© Semiconductor Components Industries, LLC, 2014

April, 2014 − Rev. 5

1

Publication Order Number:

NCP6361/D

NCP6361

Buck Converter with

Bypass Mode for RF Power

Amplifiers

The NCP6361, a PWM synchronous step−down DC−to−DC

converter, is optimized for supplying RF Power Amplifiers (PAs) used

in 3G/4G wireless systems (Mobile / Smart Phones, Tablets,

…)

powered by single−cell Lithium−Ion batteries. The device is able to

deliver up to 2 A current in bypass mode and 800 mA in buck mode.

The output voltage is monitorable from 0.4 V to 3.5 V by an analog

control pin VCON. The analog control allows dynamically optimizing

the RF Power Amplifier’s efficiency through the monitoring of the PA

output power. With an improved overall system efficiency the

communication time and phone autonomy can be consequently

increased. At light load for optimizing the DC−to−DC converter

efficiency, the NCP6361 enters automatically in PFM mode and

operates in a slower switching frequency. The NCP6361 enters in

bypass mode when the desired output voltage becomes close to the

input voltage (e.g.: low battery conditions). The device operates at

3.429 MHz or 6 MHz switching frequency. This way the system

tuning can focus respectively either on a better efficiency (3.249 MHz)

or on employing smaller value inductor and capacitors (6 MHz).

Synchronous rectification and automatic PFM / PWM / By−Pass

operating mode transitions improve overall solution efficiency. The

NCP6361 has two versions: NCP6361A and NCP6361B. Version B

has a spread spectrum function for low EMI operation. The NCP6361

is available in a space saving, low profile 1.36 x 1.22 mm CSP−9

package.

Features

Applications

Optimized Footprint and Solution Thickness

Efficiency

Typical Applications

Battery or

System

Supply

10uF

0.47uH

4.7uF

V

NCP6361

FB

PVIN

SW

PGND

Enabling

Thermal

Protection

BPEN

EN

AGND

Bypass Control

VCON

Vout Control

Bypass

DCDC

1.0A

3.43/6.00 MHz

VBATT

Bypass

Enable

Figure 1. NCP6361 Block Diagram

OUT

FSEL

WLCSP9

CASE 567GM

MARKING

DIAGRAM

http://onsemi.com

See detailed ordering, marking and shipping information on

page 19 of this data sheet.

ORDERING INFORMATION

6361x = Specific Device Code

x = A or B

A

= Assembly Location

L

= Wafer Lot

Y

= Year

WW = Work Week

G

= Pb−Free Package

6361x

ALYWW

G