LTM4670 Low VIN Quad μModule® Regulator

ADI's LTM4670 is a quad DC/DC step-down μModule® (micromodule) regulator with 10 A per output. Outputs can be paralleled in an array for up to 40 A capability. The package includes the switching controller, power MOSFETs, inductor, and all support components. Operating over an input voltage range of 2.25 V to 5.5 V, each output voltage ranges from 0.5 V to VIN set by only one external resistor. Its high-efficiency design delivers 10 A continuous output current per channel. Only a few input and output capacitors are needed.

The LTM4670 employs a Silent Switcher®2 architecture with internal hot loop bypass capacitors to achieve both low EMI and high efficiency. The default frequency is internally set to 2 MHz; it can be externally synchronized to a clock from 1 MHz to 2.6 MHz.

Fault protection features include overvoltage, overcurrent, and overtemperature protection. The LTM4670 is Pb-free and RoHS compliant.

Demonstration circuit DC2891A features the LTM4670EY, a high efficiency, quad 10 A step-down power μModule regulator. The input voltage range is from 2.25 V to 5.5 V. The output voltage range is 0.5 V to V_IN. Derating is necessary for certain V_IN, V_OUT, frequency, and thermal conditions. The DC2891A offers the SSTT pin, allowing the user to program output tracking, soft-start period, and die temperature monitoring.

The MODE/SYNC pin either synchronizes the switching frequency to an external clock, is a clock output, or sets the PWM mode. The PWM modes of operation are forced continuous mode for low noise or pulse-skipping mode for high efficiency at light load. The LTM4670 defaults to forced continuous mode in regulation and during synchronization. The LTM4670 operates in pulse-skipping mode when both the FREQ and MODE/SYNC pins are connected to V_IN.

DC2891A has optional jumper resistors to parallel multiple LTM4670 channels. For paralleled channels, one channel can be set as master, and the rest can be set as slaves. The phase shift of a slave channel relative to the master channel can be programmed with a resistor divider on the FREQ pin.

For DC2891A, four channels of LTM4670 are working separately and all set as master. A multiphase oscillator LTC6902 is used to set a 90 degree phase shift between adjacent phases and reduce the amount of ripple current in both the input and output capacitors.

Features

• Quad output array that can also be configured as single, dual, or triple output
• Supports up to 40 A currents, or 10 A output current per channel
• Minimizes solution space in 7.5 mm x 15 mm BGA package