DESCRIPTION
The NB681 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, and EOPIO. It offers a very
compact solution to achieve a 6A continuous
output current and a 7.5A peak output current
over a wide input supply range.
The NB681 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, NB681 provides lowpower 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
2mm x 3 mm package.

FEATURES
 Wide 4.5V to 28V Operating Input Range
 VCCIO/PRIMCORE/EDRAM/EOPIO/V1.0A
Compatible for IMVP8
 Output Adjustable by 2-Bit VID
 Low-Power Mode
 25µA Low Quiescent Current
 6A 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 2mm x 3mm Package

APPLICATIONS
 Laptop Computers
 Tablet PCs
 Networking Systems
 Servers
 Personal Video Recorders
 Flat Panel Televisions and Monitors
 Distributed Power Systems