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LTM4616

4616fa

SIMPLIFIED BLOCK DIAGRAM

SYMBOL

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

CIN1

CIN2

External Input Capacitor Requirement

(VIN1 = 2.7V to 5.5V, VOUT1 = 1.5V)

(VIN2 = 2.7V to 5.5V, VOUT2 = 2.5V)

IOUT1 = 8A

IOUT2 = 8A

μF

COUT1

COUT2

External Output Capacitor Requirement

(VIN1 = 2.7V to 5.5V, VOUT1 = 1.5V)

(VIN2 = 2.7V to 5.5V, VOUT2 = 2.5V)

IOUT1 = 8A

IOUT2 = 8A

100

μF

Table 1. Decoupling Requirements. TA = 25°C, Block Diagram Conﬁguration.

The LTM4616 is a dual-output standalone nonisolated

switching mode DC/DC power supply. It can provide two

8A outputs with few external input and output capacitors.

This module provides precisely regulated output voltages

programmable via external resistors from 0.6VDC to 5VDC

over 2.7V to 5.5V input voltages. The typical application

schematic is shown in Figure 18.

The LTM4616 has integrated constant frequency current

mode regulators and built-in power MOSFET devices with

fast switching speed. The typical switching frequency is

1.5MHz. For switching noise sensitive applications, it can

be externally synchronized from 0.75MHz to 2.25MHz.

Even spread spectrum switching can be implemented in

the design to reduce noise.

With current mode control and internal feedback loop

compensation, the LTM4616 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 thermal shutdown in an overcurrent condition.

Internal overvoltage and undervoltage comparators pull

the open-drain PGOOD output low if the output feedback

voltage exits a ±10% window around the regulation point.

The power good pins are disabled during margining.

Pulling the RUN pins below 1.3V forces the regulators

into a shutdown state, by turning off both MOSFETs. The

TRACK pin is used for programming the output voltage

ramp and voltage tracking during start-up. See Applica-

tions Information section.

The LTM4616 is internally compensated to be stable over

all operating conditions. Table 3 provides a guideline for

input and output capacitances for several operating condi-

tions. The Linear Technology μModule Power Design Tool

will be provided for transient and stability analysis. The

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

external resistor to ground.

Multiphase operation can be easily employed with the

synchronization and phase mode controls. Up to 12 phases

can be cascaded to run simultaneously with respect to each

other by programming the PHMODE pin to different levels.

The LTM4616 has clock in and clock out for poly phasing

multiple devices or frequency synchronization.

High efﬁciency at light loads can be accomplished with

selectable Burst Mode operation using the MODE pin. These

light load features will accommodate battery operation.

Efﬁciency graphs are provided for light load operation in

the Typical Performance Characteristics section.

Output voltage margining is supported, and can be pro-

gramed from ±5% to ±15% using the MGN and BSEL

pins.

OPERATION

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