LINEAR dn430f Data Handbook

8A Low Voltage, Low Profi le DC/DC µModule Regulator in 9mm × 15mm Package Weighs Only 1g Design Note 430 Eddie Beville and Alan Chern

Introduction and a frequency spread spectrum feature can also be In communications, industrial and other high power activated to further reduce switching noise harmonics. systems, board-mounted point-of-load (POL) DC/DC The device supports output voltage tracking or simpler power supplies simplify thermal management and offer supply rail sequencing. Programmable output voltage high performance. An ideal POL power supply module margining is supported for ±5%, ±10%, and ±15% levels. takes a minimal amount of space and mounts on the Fault protection features include over voltage protection, board much like other surface mount ICs without special over current protection, and thermal shutdown.

tooling. It should also demonstrate exceptional thermal

Quick and Easy Design

performance with excellent effi ciency and low power FF IC IE

Figure 2 shows a typical 1.8V output design; its effi ciency

dissipation.

is shown in Figure 3. Because the LTM4608 includes 8A DC/DC μModule™ Regulator in an IC Form Factor two integrated 10μF ceramic capacitors, additional input capacitors are only needed for large load steps up to

The LTM4608® μModule regulator is a complete high

the full 8A level. Linear Technology provides a μModule

density power supply in a low profi le (15mm × 9mm ×

2.8mm) LGA surface mount package (Figure 1). Its small , LT, LTC and LTM are registered trademarks of Linear Technology. μModule and Switcher CAD are trademarks of Linear Technology Corporation.

form factor houses the switching controller, MOSFETs, All other trademarks are the property of their respective owners. inductor and all support components, and weighs only 1g.

At this size, it can be mounted on the back side of a system CLKIN VOUT

VIN VOUT 1.8V

3V TO 5.5V

board, taking advantage of otherwise unused space. 8A SVIN FB 100μF10μF

SW ITH 4.87k

LTM4608 RUN ITHM

PLLLPF PGOOD

TRACK MGN CLKOUT GND SGND

DN430 F02

Figure 1. The LTM4608 Offers High Power Density

in a 9mm × 15mm × 2.8mm LGA Package Figure 2. Few Components Are Required for a 1.8V/8A Application

The LTM4608 operates from an input supply range of 2.375 to 5.5V, and a single resistor is all that is needed to set the output voltage within a 0.6V to 5V output range. Its high effi ciency design and low thermal impedance VIN = 3.3V package delivers up to 8A continuous current.

VIN = 5V

Wealth of Features The LTM4608’s 1.5MHz switching frequency and current mode architecture allow it to react quickly to line and load transients without sacrifi cing stability. Cycle-by-cycle

VOUT = 1.8V

current mode control also enables excellent current shar-

LOAD CURRENT (A) DN430 F03

ing for parallel operation. The integrated clock enables multiphase operation and frequency synchronization, Figure 3. Effi ciency of the Application in Figure 2