説明

The LTM4622 is a complete dual 2.5A step-down switch-ing mode power μModule (power module) regulator in a tiny ultrathin 6.25mm × 6.25mm × 1.82mm LGA and 6.25mm × 6.25mm × 2.42mm BGA packages. Included in the package is the switching controller, the power FETs, the inductor, and the supporting components. Operating over an input voltage range of 3.6V to 20V, the LTM4622 supports an output voltage range of 0.6V to 5.5V, set by a single external resistor. Its high efficiency design delivers dual 2.5A continuous, 3A peak, output current. Only a few ceramic input and output capacitors are needed.

The LTM4622 supports selectable Burst Mode operation and output voltage tracking for supply rail sequencing. Its high switching frequency and current mode control enable a very fast transient response to line and load changes without sacrificing stability.

Fault protection features include input overvoltage, out-put overcurrent and overtemperature protection. The LTM4622 is available with SnPb (BGA) or RoHS-compliant terminal finish.

 

特徴

Complete Solution in <1cm2

Wide Input Voltage Range: 3.6V to 20V

3.3V Input Compatible with VIN Tied to INTVCC

0.6V～5.5V 出力電圧

Dual 2.5A (3A Peak) or Single 5A Output Current

±1.5% Maximum Total Output Voltage Regulation Error Over Load, Line, and Temperature

電流モード制御、高速過渡応答

外部周波数同期

Multiphase Parallelable with Current Sharing

Output Voltage Tracking and Soft-Start Capability

選択可能なバースト・モード®動作

Overvoltage Input and Overtemperature Protection

Power Good Indicators

6.25mm × 6.25mm × 1.82mm LGA and 6.25mm × 6.25mm × 2.42mm BGA Packages

 

アプリケーション

General Purpose Point-of-Load Conversion

通信機器、ネットワーク機器、産業機器

Medical Diagnostic Equipment

Test and Debug Systems

 

オペレーション

The LTM4622 is a dual output standalone nonisolated switch mode DC/DC power supply. It can deliver two 2.5A DC, 3A peak output current with few external input and output ceramic capacitors. This module provides dual precisely regulated output voltage programmable via two external resistor from 0.6V to 5.5V over 3.6V to 20V input voltage range. With INTVCC tied to VIN, this module is able to operate from 3.3V input. The typical application schematic is shown in Figure 24.

The LTM4622 contains an integrated controlled on-time valley current mode regulator, power MOSFETs, inductor, and other supporting discrete components. The default switching frequency is 1MHz. For output voltages between 2.5V and 5.5V, an external resistor is required between FREQ and GND pins to set the operating frequency to higher frequency to optimize inductor current ripple. For switching noise-sensitive applications, the switching frequency can be adjusted by external resistors and the μModule regulator can be externally synchronized to a clock within ±30% of the set frequency. See the Applications Information section.

With current mode control and internal feedback loop compensation, the LTM4622 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 limiting. An internal overvoltage and undervoltage comparators pull the open-drain PGOOD output low if the out-put feedback voltage exits a ±8% window around the regulation point. Furthermore, an input overvoltage protection been utilized by shutting down both power MOSFETs when VIN rises above 22.5V to protect internal devices.

Multiphase operation can be easily employed by connecting SYNC pin to an external oscillator. Up to 6 phases can be paralleled to run simultaneously a good current sharing guaranteed by current mode control loop.

Pulling the RUN pin below 1V forces the controller into its shutdown state, turning off both power MOSFETs and most of the internal control circuitry. At light load cur-rents, Burst Mode operation can be enabled to achieve higher efficiency compared to continuous mode (CCM) by setting MODE pin to INTVCC. The TRACK/SS pin is used for power supply tracking and soft-start programming.