LTM4604AV Ver la hoja de datos (PDF) - Analog Devices

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LTM4604AV

Low Voltage, 4A DC/DC µModule Regulator with Tracking

Analog Devices 

LTM4604A

OPERATION

Power Module Description

The LTM4604A is a standalone non-isolated switch mode

DC/DC power supply. It can deliver up to 4A of DC output

current with few external input and output capacitors.

This module provides a precise regulated output voltage

programmable via one external resistor from 0.8V DC to

5.0V DC over a 2.375V to 5.5V input voltage. A typical

application schematic is shown in Figure 15.

The LTM4604A has an integrated constant frequency cur-

rent mode regulator with built-in power MOSFETs with

fast switching speed. The typical switching frequency is

1.25MHz. With current mode control and internal feed-

back loop compensation, the LTM4604A module has suf-

ficient stability margins and good transient performance

under a wide range of operating conditions and with a

wide range of output capacitors, even all ceramic output

capacitors.

Current mode control provides cycle-by-cycle fast cur-

rent limit. In addition, foldback current limiting is pro-

vided in an overcurrent condition while VOUT drops.

Internal overvoltage and undervoltage comparators pull

the open-drain PGOOD output low if the output feedback

voltage exits a ±7.5% window around the regulation point.

Furthermore, in an overvoltage condition, internal top FET

M1 is turned off and bottom FET M2 is turned on and held

on until the overvoltage condition clears.

Pulling the RUN/SS pin below 0.5V forces the control-

ler into its shutdown state, turning off both M1 and M2.

At low load current, the module works in continuous

current mode by default to achieve minimum output

voltage ripple.

The TRACK pin is used for power supply tracking. See the

Applications Information section.

The LTM4604A is internally compensated to be stable

over a wide operating range. Table 4 provides a guideline

for input and output capacitance for several operating

conditions. The LTpowerCAD® GUI is available for tran-

sient and stability analysis.

The FB pin is used to program the output voltage with a

single external resistor connected to ground.

Rev. D

For more information www.analog.com

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