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07-04-2017

17 V, 4 MHz, Dual 3.5 A Synchronous Buck with Spread Spectrum Modulation Reduces EMI in a Compact 3 mm x 5 mm QFN

Analog Devices » LTC7124

Analog Devices, which recently acquired Linear Technology Corporation, announces the LTC7124, a high efficiency, 4 MHz synchronous dual output buck regulator that incorporates a constant frequency, peak current mode architecture. Optional spread spectrum frequency modulation is integrated for reducing radiated and conductive EMI noise. The device can deliver up to 3.5 A of continuous output current from each channel or generate a 2-phase single output up to 7 A in a compact 3 mm × 5 mm footprint package. The switching frequency is user programmable from 500 kHz to 4 MHz, enabling the use of tiny, low cost capacitors and inductors; also included is external clock synchronization capability for noise-sensitive applications. The LTC7124 operates from an input voltage of 3.1 V to 17 V with an output voltage range of 0.6 V to 99% of VIN, with high ±1% VOUT accuracy, ideal for 1-4 cell Li-Ion applications as well as 5 V and 12 V intermediate bus systems. Other key applications include battery-powered systems, point-of-load supplies, portable instruments and handheld scanners.

Analog Devices - LTC7124

Each channel of the LTC7124 uses internal N-channel MOSFET switches with RDS(ON) of only 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 only 8 μA with both channels enabled and only 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.

1.8 V/3.3 V 1 MHz Step-Down Regulator
1.8 V/3.3 V 1 MHz Step-Down Regulator.

The LTC7124 is available in a thermally enhanced 3 mm × 5 mm 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 each in 1,000-piece quantities. All versions are available from stock.

Efficiency & Power Loss vs Load Current at 1 MHz
Efficiency & Power Loss vs Load Current at 1 MHz.

Summary of Features: LTC7124

  • Wide VIN Range: 3.1 V to 17 V
  • Wide VOUT Range: 0.6 V to 99% VIN
  • Dual Step-Down Outputs: 3.5 A per Channel
  • Spread Spectrum Modulation for Low Radiated & Conductive Noise
  • Integrated 80 mW/40 mW N-Channel MOSFETs Provide Up to 95% Efficiency
  • No-Load IQ < 8 µA with Both Channels Enabled; IQ < 5.5 µA with Only One Channel Enabled
  • Programmable Frequency (500 kHz to 4 MHz) with ±25% Frequency Synchronization Range
  • Configurable for a 2-Phase Single Output at up to 7 A
  • ±1% Output Voltage Accuracy
  • Current Mode Operation for Excellent Line & Load Transient Response
  • Internal or External Loop Compensation
  • Thermally Enhanced 3 mm × 5 mm QFN-24 Package
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