High-Efficiency, Fast-Transient, 8A, 24V, Low Rds(on) 26mO/12mO, Fully-Integrated COT Synchronous Buck with 3.3V LDO
The NB677 is a fully integrated high frequency synchronous rectified step-down switch mode converter with 3.3V fixed output voltage. It offers very compact solution to achieve 8A continuous output current and 10A peak output current over a wide input supply range with excellent load and line regulation. The NB677 operates at high efficiency over a wide output current load range. Constant-On-Time (COT) control mode provides fast transient response and eases loop stabilization.
Under voltage lockout is internally set as 4.65 V. An open drain power good signal indicates the output is within its nominal voltage range.
NB677 also provides a 3.3V LDO, which can be used to power the external peripheries, such as the keyboard controller in the laptop computer. A 300kHz CLK is also available; its output can be used to drive an external charge pump, generating gate drive voltage for the load switches without reducing the main converter’s efficiency.
Full protection features include OCP, OVP, UVP and thermal shut down.
The converter requires minimum number of external components and is available in QFN16 (3mmx3mm) package.
- Wide 5.5V to 24V Operating Input Range
- 3.3V Fixed Output Voltage
- Built-in 3.3V, 100mA LDO with Switches
- 8A Continuous Output Current
- 10A Peak Output Current
- 300kHZ CLK for External Charge Pump
- 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
- fsw (max) (kHz)500
- Vin (max) (V)24
- Iout (max) (A)8
- Isw Limit (typ) (A)9
- Vfb (typ) (V)0.6
- Iq (typ) (mA)0.205
- PackageQFN-16 (3x3)
- Control ModeCOT
- Common FeaturesLight-Load Efficiency, Power Good, Synchronous Rectification
- Special FeaturesFixed Output, Output Discharge