36VIN, 3A, High Efficiency Synchronous Step-Down Converter with Low Quiescent Current


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The RTQ2105 is a 3A, high-efficiency, current mode synchronous step-down converter which is optimized for automotive applications. The device operates with input voltages from 3V to 36V and is protected from load dump transients up to 42V, eases input surge protection design. The device can program the output voltage between 0.8V to VIN. The low quiescent current design with the integrated low RDS(ON) power MOSFETs achieves high efficiency over the wide load range. The peak current mode control with simple external compensation allows the use of small inductors and results in fast transient response and good loop stability.

The wide switching frequency of 300kHz to 2200kHz allows for efficiency and size optimization when selecting the output filter components. The ultra-low minimum on-time enable constant-frequency operation even at very high step-down ratios. For switching noise sensitive applications, it can be externally synchronized from 300kHz to 2200kHz. The optional spread-spectrum frequency modulation further helping systems designers with better EMC management.

The RTQ2105 offers precise constant current and constant voltage regulation. It is ideally suited for USB power delivery or charging super-capacitors. For applications that use long cable, the RTQ2105 offers cable drop compensation as well to maintain accurate regulation at the end of the long cable.

The RTQ2105 provides complete protection functions such as input under voltage lockout, output under voltage protection, over current protection, and thermal shutdown. Cycle-by-cycle current limit provides protection against shorted outputs and soft-start eliminates input current surge during start-up. The RTQ2105 is available in WET-WQFN-24SL 4x4 (W-Type) package.


  • Automotive Systems
  • Car Camera Module and Car Cockpit Systems
  • Connected Car Systems
  • Point of Load Regulator in Distributed Power Systems
  • Digital Set Top Boxes
  • Broadband Communications
  • USB Power Chargers
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36VIN, 3A, High Efficiency Synchronous Step-Down Converter with Low Quiescent Current2018/11/09
Reference Design
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Richtek Load Transient Tool2019/01/09