High-Effeciency, Fast-Transient, 6A, 24V, Fully-Integrated COT Synchronous Buck with +/-1.5A LDO and Buffed Reference

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Product Description

The NB672/NB673 provides a complete power supply for DDR3, DDR3L and LPDDR2 memory with the highest power density. It integrates a high frequency synchronous rectified step-down switch mode converter (VDDQ) with a 1.5A sink/source LDO (VTT) and buffered low noise reference (VTTREF). The fully integrated Buck converter of NB672/NB673 is able to deliver 6A/8A continuous output current and 8A/10A peak output current over a wide input supply range with excellent load and line regulation. The Buck converter employs the Constant-On-Time (COT) control scheme, which provides fast transient response and eases loop stabilization. The VTT LDO provides 1.5A sink/source current capability and requires only 10uF ceramic capacitance. The VTTREF tracks VDDQ/2 with an excellent 1% accuracy. Under voltage lockout is internally set as 4.5V. An open drain power good signal indicates VDDQ is within its nominal voltage range. Full protection features include OCP, OVP, and thermal shut down. These two parts require minimum number of external components and are available in QFN21 (3mmx4mm) package.


Product Features

  • Wide 5V to 24V Operating Input Range
  • 6A Continuous Output Current and 8A Peak Output Current (NB672)
  • 8A Continuous Output Current and 10A Peak Output Current (NB673)
  • Built-in +/- 1.5A VTTLDO
  • Low RDS(ON) Internal Power MOSFETs
  • Proprietary Switching Loss Reduction Technique
  • Internal Soft Start
  • Output Discharge
  • 500kHZ Switching Frequency
  • OCP, OVP, UVP Protection and Thermal Shutdown
  • VDDQ Adjustable from 0.604V to 5.5V


  • fsw (max) (kHz)500
  • Vin (min) (V)5
  • Vin (max) (V)24
  • Iout (max) (A)6
  • Isw Limit (typ) (A)8.5
  • Vfb (typ) (V)0.604
  • Iq (typ) (mA)0.4
  • Regulated Outputs1
  • Vout (max) (V)5.5
  • Vout (min) (V)0.604
  • GradeCatalog
  • PackageQFN-21 (3x4)
  • Control ModeCOT
  • Common FeaturesLight-Load Efficiency, Power Good, Synchronous Rectification
  • Special FeaturesOutput Discharge