FTM Board Club
Fairchild Semiconductor
Synchronous Buck Regulator (3MHz, 3A).

The FAN5353/54 evaluation board is a compact circuit including Fairchild`s FAN5353/54 ajustable output (Vout by default set at 1.2V), step down switching voltage regulator in a 12 lead MLP 3x3.5 Package.

One 10uF input capacitor, 2 x 10uF output capacitors and one 0.47uH inductor are installed on the board to ensure tight regulation, low ripple and excellent transiant response. It also provides excellent probe access.

The FAN5353 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 FAN5353 is capable of delivering 3A at over 85% efficiency, while maintaining a very high efficiency of up to 90%. 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 10ľF for the output capacitor. Additional output capacitance can be added without affecting stability if tighter regulation during transients is required. The regulator includes an open-drain power good (PGOOD) signal that pulls low when the output is not in regulation. In shutdown mode, the supply current drops below 1ľA, reducing power consumption. FAN5353 is available in a 12-lead 3x3.5mm MLP package.


• 3MHz Fixed-Frequency Operation
• Best-in-Class Load Transient
• 3A Output Current Capability
• 2.7V to 5.5V Input Voltage Range
• Adjustable Output Voltage: 0.8V to VINx0.9
• Power Good Output
• Internal Soft-Start
• Input Under-Voltage Lockout (UVLO)
• Thermal Shutdown and Overload Protection
• 12-lead 3x3.5mm MLP