Spread spectrum modulation cuts noise from 17V, 4 MHz, 2x 3.5A buck DC/DC

Spread spectrum modulation cuts noise from 17V, 4 MHz, 2x 3.5A buck DC/DC

New Products |
By Graham Prophet

The device can deliver up to 3.5A of continuous output current from each channel or generate a 2-phase single output up to 7A in a 3 x 5 mm footprint package. The switching frequency is user-programmable from 500 kHz to 4 MHz, enabling the use of small, low cost capacitors and inductors; also included is external clock synchronization capability for noise-sensitive applications. The LTC7124 operates from an input voltage of 3.1V to 17V with an output voltage range of 0.6V to 99% of VIN, with ±1% VOUT accuracy, for 1-4 cell Li-Ion applications as well as 5V and 12V intermediate bus systems. Other key applications include battery-powered systems, point-of-load supplies, portable instruments and handheld scanners.


Each channel of the LTC7124 uses internal N-channel MOSFET switches with RDS (ON) of 80 mΩ and 40 mΩ to deliver efficiencies as high as 95%. The two channels run 180 degrees out-of-phase, minimizing the size of both input and output capacitance. User-selectable Burst Mode operation is used to maximize light load efficiency, requiring 8 µA with both channels enabled and 5.5 µA of quiescent current with one channel enabled. For applications requiring the lowest possible noise, the LTC7124 can be configured to run in forced continuous operation, reducing output voltage ripple and potential RF interference. Additional features include input overvoltage and overtemperature protection, power good voltage monitors, independent soft-start capability for each channel, internal or external loop compensation, programmable current limit and short-circuit protection.


In a thermally enhanced QFN-24 package, E- and I-grade versions are guaranteed to operate over the –40°C to 125°C operating junction temperature. The E-grade is priced starting at $4.05 (1000).


Analog Devices/Linear Technology;



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