ltm4619 Linear Technology Corporation, ltm4619 Datasheet - Page 8

• Manufacturer Part Number: ltm4619
• Description: Dual, 26vin, 4a Dc/dc ?module Regulator
• Manufacturer: Linear Technology Corporation

OPERATION
LTM4619
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 suffi cient 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
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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 V
output voltage with a single external resistor to ground.
Multiphase operation can be easily employed with the
synchronization.
High effi ciency at light loads can be accomplished with
selectable Burst Mode operation or pulse-skipping mode
using the MODE pin. Effi ciency graphs are provided for
light load operations in the Typical Performance Charac-
teristics section.
FB
pin is used to program the
4619f