FAN5354: 3Mhz, 3A Synchronous Buck Regulator

The FAN5354 is a step-down switching voltage regulator that delivers an adjustable output from an input voltage supply of 2.7V to 5.5V. Using a proprietary architecture with synchronous rectification, the FAN5354 is capable of delivering 3A at over 85% efficiency, while maintaining a very high efficiency of over 80% at load currents as low as 2mA. The regulator operates at a nominal fixed frequency of 3MHz, which reduces the value of the external components to 470nH for the output inductor and 10µF for the output capacitor. Additional output capacitance can be added to improve regulation during load transients without affecting stability and inductance up to 1.2µH may be used with additional output capacitance.

At moderate and light loads, pulse frequency modulation (PFM) is used to operate the device in power-save mode with a typical quiescent current of 270µA. Even with such a low quiescent current, the part exhibits excellent transient response during large load swings. At higher loads, the system automatically switches to fixed-frequency control, operating at 3MHz. In shutdown mode, the supply current drops below 1µA, reducing power consumption. PFM mode can be disabled if constant frequency is desired. To avoid audible noise, the regulator limits its minimum PFM frequency. The FAN5354 is available in 12-lead 3x3.5mm MLP package.

Features

• 3MHz Fixed-Frequency Operation
• Best-in-Class Load Transient
• 3A Output Current Capability
• 2.7V to 5.5V Input Voltage Range
• Adjustable Output Voltage: 0.8 to 2.0 V
• PFM Mode for High Efficiency in Light Load (Forced PWM Available on MODE Pin)
• Minimum PFM Frequency Avoids Audible Noise
• 270µA Typical Quiescent Current in PFM Mode
• External Frequency Synchronization
• Low Ripple Light-Load PFM Mode with Forced PWM Control
• Power Good Output
• Internal Soft-Start
• Input Under-Voltage Lockout (UVLO)
• Thermal Shutdown and Overload Protection
• 12-Lead 3x3.5mm MLP