Synchronous Buck PWM,

Step-Down, DC-to-DC Controller

ADP1828

Rev. 0

InformationfurnishedbyAnalogDevicesisbelievedtobeaccurateandreliable.However,no

responsibilityisassumedbyAnalogDevicesforitsuse,norforanyinfringementsofpatentsorother

rightsofthirdpartiesthatmayresultfromitsuse.Specificationssubjecttochangewithoutnotice.No

licenseisgrantedbyimplicationorotherwiseunderanypatentorpatentrightsofAnalogDevices.

Trademarksandregisteredtrademarksarethepropertyoftheirrespectiveowners.

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.

Tel: 781.329.4700

www.analog.com

Fax: 781.461.3113

©2007 Analog Devices, Inc. All rights reserved.

FEATURES

Wide bias voltage range 3.0 V to 18 V

Wide power stage input range 1 V to 24 V

Wide output voltage range: 0.6 V to 85% of input voltage

All N-channel MOSFET design for low cost

Fixed-frequency operation at 300 kHz, 600 kHz, or resistor

adjustable 300 kHz to 600 kHz

Clock output for synchronizing other controllers

No current sense resistor required

Internal linear regulator

Voltage tracking for sequencing

Soft start and thermal overload protection

Overvoltage and undervoltage power-good indicator

15 μA shutdown supply current

Available in a 20-lead QSOP

APPLICATIONS

Telecom and networking systems

Base station power

Set-top boxes, game consoles

Printers and copiers

Medical imaging systems

DSP and microprocessor core power supplies

DDR termination

GENERAL DESCRIPTION

The ADP1828 is a versatile and synchronous PWM voltage

mode buck controller. It drives an all N-channel power stage

to regulate an output voltage as low as 0.6 V to 85% of the input

voltage and is sized to handle large MOSFETs for point-of-load

regulators. The ADP1828 is ideal for a wide range of high power

applications, such as DSP and processor core I/O power, and

general-purpose power in telecommunications, medical imaging,

PC, gaming, and industrial applications. It operates from input

bias voltages of 3 V to 18 V with an internal LDO that generates

a 5 V output for input bias voltages greater than 5.5 V.

The ADP1828 operates at a pin-selectable, fixed switching

frequency of either 300 kHz or 600 kHz, or at any frequency

between 300 kHz and 600 kHz with a resistor. The switching

frequency can also be synchronized to an external clock up to

2× the part’s nominal oscillator frequency. The clock output

can be used for synchronizing additional ADP1828s (or the

ADP1829 controllers), thus eliminating the need for an external

clock source. The ADP1828 includes soft start protection to

limit any inrush current from the input supply during startup,

reverse current protection during soft start for a precharged

output, as well as a unique adjustable lossless current-limit

For applications requiring power-supply sequencing, the

ADP1828 provides a tracking input that allows the output

voltage to track during startup, shutdown, and faults. The

additional supervisory and control features include thermal

overload, undervoltage lockout, and power good.

The ADP1828 operates over the −40°C to +125°C junction

temperature range and is available in a 20-lead QSOP.

IN

VREG

EN

FREQ

SYNC

PGOOD

COMP

SS

200nF

L1 = 0.82µH

M1

M2

×2

180µF

×2

20V

DH

BST

SW

CSL

DL

PGND

CLKOUT

CLKSET

FB

C4

0.47µF

PV

TRK

ADP1828

1.8kΩ

OUTPUT

1.8V, 20A

C6

1µF

R8

20kΩ

C3

5.6nF

PGND

AGND

C2

33pF

R1

20kΩ

R3

7.5kΩ

R2

10kΩ

D1

47µF

X5R

6.3V

1000µF

×2

C1

680pF

R6

100kΩ

C7

1µF

C5

1µF

GND

AGND

D1: BAT54

M1: INFINEON, BSC080N03LS

M2: INFINEON, 2 × BSC030N03LS

L1: WURTH ELEKTRONIC, 0.82µH, 744355182

Figure 1. Typical Application Circuit with 20 A Output