BESCHREIBUNG

The LTMR4620A is a complete dual 13A, or single 26A output switching mode DC/DC power supply with wider VOUT range and higher efficiency than the LTM4620. Included in the package are the switching controller, power FETs,

inductors and all supporting components. Operating from an input voltage range of 4.5V to 16V, the LTM4620A supports two outputs each with an output voltage range of 0.6V to 5.3V, set by a single external resistor. Its high

efficiency design delivers up to 13A continuous current for each output. Only a few input and output capacitors are needed.

The device supports frequency synchronization, multiphase operation, Burst Mode operation and output voltage tracking for supply rail sequencing and has an onboard temperature diode for device temperature monitoring.High switching frequency and a current mode architecture enable a very fast transient response to line and load changes without sacrificing stability.

Fault protection features include overvoltage and overcurrent protection. The power module is offered in a proprietary space saving and thermally enhanced

15mm × 15mm × 4.41mm LGA package and 15mm× 15mm × 5.01mm BGA package. The LTM4620A is available with SnPb (BGA) or RoHS compliant terminal finish.

 

FEATURES

Dual 13A or Single 26A Output

Wide Input Voltage Range: 4.5V to 16V

Output Voltage Range: 0.6V to 5.3V

±1.5% Maximaler Gesamtfehler des DC-Ausgangs

Multiphase Current Sharing with Multiple LTM4620As Up to 100A

Higher Efficiency and Wider VOUT Range Than LTM4620

Differential-Fernerkennungsverstärker

Steuerung im Strommodus/schnelles Einschwingverhalten

Einstellbare Schaltfrequenz

Überstromschutz (Foldback)

Frequenz-Synchronisation

Interner Temperaturmonitor

Überspannungsschutz am Ausgang

Pin Compatible with the LTM4628 (Dual 8A) and LTM4620 (Dual 13A)

Thermally Enhanced (15mm × 15mm × 4.41mm)

LGA Package

 

ANWENDUNGEN

Telekommunikations- und Netzwerkausrüstung

Industrielle Ausrüstung

 

OPERATION

Power Module Description

The LTM4620A is a dual-output standalone nonisolated switching mode DC/DC power supply. It can provide two 13A outputs with few external input and output capacitors and setup components. This module provides precisely regulated output voltages programmable via external resistors from 0.6VDC to 5.3VDC over 4.5V to 16V input voltages.

The LTM4620A has dual integrated constant-frequency current mode regulators and built-in power MOSFET devices with fast switching speed. The typical switching frequency is 500kHz. For switching-noise sensitive applications,it can be externally synchronized from 400kHz to 780kHz. A resistor can be used to program a free run frequency on the fSET pin.

With current mode control and internal feedback loop compensation, the LTM4620A module has sufficient stability 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 foldback current limit in an overcurrent condition. Internal overvoltage and undervoltage comparators pull the open-drain PGOOD outputs low if the output feedback voltage exits a ±10% window around the regulation point. As the output voltage exceeds 10% above regulation, the bottom MOSFET will turn on to clamp the output voltage. The top MOSFET will be turned off. This overvoltage protect is feedback voltage referred.

Pulling the RUN pins below 1.1V forces the regulators into a shutdown state, by turning off both MOSFETs. The TRACK pins are used for programming the output voltage ramp and voltage tracking during start-up or used for soft-starting the regulator.

The LTM4620A is internally compensated to be stable over all operating conditions. Table 5 provides a guide line for input and output capacitances for several operating conditions. LTpowerCADR is available for transient and stability analysis. The VFB pin is used to program the output voltage with a single external resistor to ground.A differential remote sense amplifier is available for sensingthe output voltage accurately on one of the outputs at the load point, or in parallel operation sensing the output voltage at the load point.

Multiphase operation can be easily employed with the MODE_PLLIN, PHASMD, and CLKOUT pins. Up to 12 phases can be cascaded to run simultaneously with respect to each other by programming the PHMODE pin to different levels. See the Applications Information section. High efficiency at light loads can be accomplished with selectable Burst Mode operation or pulse-skipping 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.

A TEMP pin is provided to allow the internal device temperature to be monitored using an onboard diode connected PNP transistor. This diode connected PNP transistor is grounded in the module and can be used as a general temperature monitor using a device that is designed to monitor the single-ended connection.