LTM4619 Ver la hoja de datos (PDF) - Linear Technology

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LTM4619

Dual, 26VIN, 4A DC/DC µModule Regulator

Linear Technology 

LTM4619

OPERATION

The LTM4619 is a dual-output standalone non-isolated

switching mode DC/DC power supply. It can deliver up to

4A (DC current) for each output with few external input and

output capacitors. This module provides precisely regulated

output voltages programmable via external resistors from

0.8VDC to 5.0VDC over 4.5V to 26.5V input voltages. The

typical application schematic is shown in Figure 18.

The LTM4619 has integrated constant frequency current

mode regulators and built-in power MOSFET devices with

fast switching speed. The typical switching frequency is

780kHz. To reduce switching noise, the two outputs are

interleaved with 180° phase internally and it can be syn-

chronized externally using the PLLIN pin.

With current mode control and internal feedback loop

compensation, the LTM4619 module has sufficient stabil-

ity margins and good transient performance with a wide

range of output capacitors, even with all ceramic output

capacitors.

Current mode control provides cycle-by-cycle fast current

limit and current foldback in a short-circuit condition.

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.

The power good pin is disabled during start-up.

Pulling the RUN pin below 1.2V forces the controller into

its shutdown state, by turning off both MOSFETs. The

TK/SS pin is used for programming the output voltage ramp

and voltage tracking during start-up. See the Applications

Information section.

The LTM4619 is internally compensated to be stable over

all operating conditions. The Linear Technology μModule

Power Design Tool will be provided for transient and

stability analysis. The VFB pin is used to program the

output voltage with a single external resistor to ground.

Multiphase operation can be easily employed with the

synchronization.

High efficiency at light loads can be accomplished with

selectable Burst Mode operation or pulse-skipping mode

using the MODE pin. Efficiency graphs are provided for

light load operations in the Typical Performance Charac-

teristics section.

4619f

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