FAN5365: 1A/0.8A, 6MHz Digitally Programmable Regulator

The FAN5365 is a high-frequency, ultra-fast transient response, synchronous step-down, DC-DC converter optimized for low-power applications using small, low-cost inductors and capacitors. The FAN5365 supports up to 800mA or 1A load current.

The FAN5365 is ideal for mobile phones and similar portable applications powered by a single-cell Lithium-Ion battery. With an output voltage range adjustable via I2C interface from 0.75V to 1.975V, it supports low-voltage DSPs and processors, core power supplies, and memory modules in smart phones, data cards, and hand-held computers. The FAN5365 operates at 6MHz (nominal) fixed switching frequency in PWM mode.

During light-load conditions, the regulator includes a PFM Mode to enhance light-load efficiency. The regulator transitions smoothly between PWM and PFM Modes with no glitches on VOUT. In hardware shutdown, the current consumption is reduced to less than 200nA.

The serial interface is compatible with Fast / Standard Mode, Fast Mode Plus, and High-Speed Mode I2C™ specifications, allowing transfers up to 3.4Mbps. This interface is used for dynamic voltage scaling with 12.5mV voltage steps, for reprogramming the mode of operation (PFM or forced PWM), or to disable/enable the output voltage.

The chip's advanced protection features include short-circuit protection and current and temperature limits. During a sustained over-current event, the IC shuts down and restarts after a delay to reduce average power dissipation into a fault.

During startup, the IC controls the output slew rate to minimize input current and output overshoot at the end of soft-start. The IC maintains a consistent soft-start ramp, regardless of output load during startup. The FAN5365 is available in a 1.27 x 1.29mm, 9-bump WLCSP package.

Features

• High Efficiency (>88%) at 6MHz
• 800mA or 1A Output Current
• Regulation Maintained with V_IN from 2.3V to 5.5V
• 6-Bit V_OUT Programmable from 0.75 to 1.975V
• 6MHz Fixed-Frequency Operation (PWM Mode)
• Excellent Load and Line Transient Response
• Small Size, 470nH Inductor Solution
• ±2% DC Voltage Accuracy in PWM Mode
• 25ns Minimum On-Time
• High-Efficiency, Low-Ripple, Light-Load PFM
• Smooth Transition between PWM and PFM
• 40µA Operating PFM Quiescent Current
• I²C-Compatible Interface up to 3.4Mbps
• Pin-Selectable or I²C™ Programmable Output Voltage
• 9-Bump, 1.27 x 1.29mm, 0.4mm Pitch WLCSP Package