Wide Vin 4.5-26V, 12A, Low Iq, High Current Synchronous Buck Converter with +/-1A LDO and Buffered Reference



The NB685 provides a complete power supply with the highest density for DDR3, DDR3L, LPDDR3, and DDR4 memory. It integrates a high-frequency, synchronous, rectified, step-down, switch-mode converter (VDDQ) with a 1 A sink/source LDO (VTT) and buffered low noise reference (VTTREF). 
The NB685 operates at high efficiency over a wide output current load range based on MPS proprietary switching loss reduction technology and internal low Ron power MOSFETs. 
Adaptive constant-on-time (COT) control mode provides fast transient response and eases loop stabilization. The DC auto-tune loop provides good load and line regulation.
The VTT LDO provides 1 A sink/source current capability and requires only 22 μF ceramic capacitors. The VTTREF tracks VDDQ/2 with excellent 1% accuracy.
Full protection features include OC limit, OVP, UVP, thermal shutdown, and over-temperature warning (OTW). 
The converter requires a minimum number of external components, and it is available in a QFN 3mm x 3mm package.



  • Wide 4.5 V to 26 V Operating Input Range
  • Compatible for IMVP8
  • 135 μA Low Quiescent Current
  • 12 A Continuous Output Current
  • 13 A Peak Output Current
  • Selectable Ultrasonic Mode
  • Selectable 500 k/700 k Switching Frequency
  • Built-In +/- 1 A VTTLDO
  • 1% Buffered VTTREF Output
  • Adaptive COT for Fast Transient
  • DC Auto-Tune Loop
  • Stable with POSCAP and Ceramic Output Capacitors
  • Over-Temperature Warning
  • Internal Soft Start
  • Output Discharge
  • OCL, OVP, UVP, and Thermal Shutdown
  • Latch-Off Re-set via EN or Power Cycle
  • QFN 3mm x 3mm Package


  • fsw (max) (kHz)700
  • 最小输入电压4.5
  • Vin (max) (V)26
  • Iout (max) (A)12
  • Isw Limit (typ) (A)13
  • Vfb (typ) (V)0.6
  • Iq (typ) (mA)0.185
  • 额定输出1
  • Vout (max) (V)3.3
  • Vout (min) (V)0.6
  • GradeCatalog
  • PackageQFN-16 (3x3)
  • Control ModeCOT
  • Common FeaturesLight-Load Efficiency, Power Good, Synchronous Rectification
  • Special FeaturesProgrammable Frequency, Soft Stop, Ultrasonic Mode