Wide Vin 4.5-26V, 6.5A, Low Iq, High Current Sync Buck with 2-Bit VID

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Product Description

The NB681A is a fully integrated, high-frequency, synchronous, rectified, step-down, switch-mode converter with 2-bit VID, especially designed for IMVP8 applications—VCCIO, PRIMCORE, V1.0A, EDRAM, EOPIO, and other POLs (1.8V/2.5V/3.3V). It offers a very compact solution to achieve a 6.5A continuous output current and a 7.5A peak output current over a wide input supply range.
The NB681A 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.
To avoid audible noise, the NB681A provides low-power mode for power loss saving during the low-power state and ultrasonic mode. 
Full protection features include OC limit, OVP, UVP, and thermal shutdown. 
The converter requires a minimal number of external components, and it is available in a QFN-13 2mm x 3mm package.


Product Features

  • Wide 4.5V to 26V Operating Input Range
  • VCCIO/PRIMCORE/EDRAM/EOPIO/V1.0A/1.8V/2.5V/3.3V Compatible for IMVP8
  • Output Adjustable by 2-Bit VID
  • Low-Power Mode
  • 25µA Low Quiescent Current
  • 6.5A Continous Output Current
  • 7.5A Peak Output Current
  • Selectable Ultrasonic Mode
  • Adaptive COT for Fast Transient
  • DC Auto-Tune Loop
  • Stable with POSCAP and Ceramic Capacitors
  • 1% Reference Voltage
  • Internal Soft Start
  • Output Discharge
  • OCL, OVP, UVP, and Thermal Shutdown
  • Latch-Off Reset via EN or Power Cycle
  • QFN-13 2mm x 3mm Package


  • fsw (max) (kHz)750
  • Vin (min) (V)4.5
  • Vin (max) (V)26
  • Iout (max) (A)6.5
  • Isw Limit (typ) (A)7.6
  • Vfb (V)0.6
  • Iq (typ) (mA)0.15
  • Regulated Outputs1
  • Vout (max) (V)3.3
  • Vout (min) (V)0
  • GradeCatalog
  • PackageQFN-13 (2x3)
  • Control ModeCOT
  • Common FeaturesLight-Load Efficiency, Power Good, Synchronous Rectification
  • Special FeaturesOutput Adjustable by 2-Bit VID, Output Discharge, Ultrasonic Mode

Reference Materials