onsemi FAN5400UCX

The FAN5400 family (FAN540x) combines a highly integrated switch-mode charger, to minimize single-cell Lithium-ion (Li-ion) charging time from a USB power source, and a boost regulator to power a USB peripheral from the battery. The charging parameters and operating modes are programmable through an I²C Interface that operates up to 3.4 Mbps. The charger and boost regulator circuits switch at 3 MHz to minimize the size of external passive components. The FAN540X provides battery charging in three phases: conditioning, constant current, and constant voltage. To ensure USB compliance and minimize charging time, the input current is limited to the value set through the I²C host. Charge termination is determined by a programmable minimum current level. A safety timer with reset control provides a safety backup for the I²C host. The integrated circuit (IC) automatically restarts the charge cycle when the battery falls below an internal threshold. If the input source is removed, the IC enters a high-impedance mode with leakage from the battery to the input prevented. Charge status is reported back to the host through the I²C port. Charge current is reduced when the die temperature reaches 120°C. The FAN540X can operate as a boost regulator on command from the system. The boost regulator includes a soft-start that limits inrush current from the battery. The FAN540X is available in a 1.96 × 1.87 mm, 20-bump, 0.4 mm pitch, WLCSP package.

• Fully Integrated, High-Efficiency Charger for Single-Cell Li-Ion and Li-Polymer Battery Packs
• Faster Charging than Linear
• Charge Voltage Accuracy: ±0.5% at 25°C, ±1% from 0 to 125°C
• ±5% Input Current Regulation Accuracy
• ±5% Charge Current Regulation Accuracy
• 20 V Absolute Maximum Input Voltage
• 6 V Maximum Input Operating Voltage
• 1.25 A Maximum Charge Rate
• Programmable through High-Speed I²C Interface (3.4 Mb/s) with Fast Mode Plus Compatibility – Input Current – Fast-Charge / Termination Current Charger Voltage – Termination Enable
• 3 MHz Synchronous Buck PWM Controller with Wide Duty Cycle Range
• Small Footprint 1 μH External Inductor
• Safety Timer with Reset Control
• 1.8 V Regulated Output from VBUS for Auxiliary Circuits
• Weak Input Sources Accommodated by Reducing Charging Current to Maintain Minimum VBUS Voltage
• Low Reverse Leakage to Prevent Battery Drain to VBUS
• 5 V, 300 mA Boost Mode for USB OTG for 2.5 to 4.5 V Battery Input

• Cell Phones, Smart Phones, PDAs
• Tablet, Portable Media Players
• Gaming Device, Digital Cameras