LTC4125IUFD 5W Self-Resonant Wireless Power Transmitter Integrated Circuit Chip 20-Lead QFN

The LTC4125IUFD is a monolithic full bridge resonant driver that delivers more than 5 W wirelessly to a properly tuned receiver. It controls the current in a series connected transmit coil and capacitor network, so the power stage is a coil, a capacitor and the driver rather than a discrete bridge with its own gate drive and control loop.

Self-Resonant switching adjusts the drive frequency to match the resonant frequency of the LC network automatically, which lets the transmitter deliver maximum power from a low voltage input between 3 V and 5.5 V. Because the loop follows the resonance instead of a fixed frequency, coil tolerance and temperature drift do not detune the system.

A periodic transmit power search adjusts the delivered power to what the receiver actually needs, which improves system efficiency at light load and limits the field when the receiver is almost charged. Power delivery stops during a fault or when a foreign object is detected.

Foreign object protection combines the power search, a programmable maximum average input current limit and an NTC input for temperature sensing, so a metal object on the pad does not heat up unchecked. The 20-lead 4 mm by 5 mm QFN keeps the driver small, and operation is specified from -40 to 125 degrees C.

The LTC4125IUFD is RoHS compliant and lead free, every order ships with full traceability, and samples and volume pricing are available on request.

• Delivers over 5 W wirelessly
• Monolithic full bridge resonant driver
• 3 V to 5.5 V input supply
• Self-Resonant frequency tracking
• Transmit power search for efficiency
• Programmable average input current limit
• NTC input for temperature protection
• Foreign object detection
• Stops delivery during a fault
• Few external components
• Low profile 4 mm by 5 mm QFN
• 20-Lead (4mm x 5mm) QFN package
• RoHS compliant, lead free

• Wireless charging pads
• Medical implant chargers
• Industrial wireless power
• Waterproof product charging
• Wearable chargers
• Sealed enclosure charging

Typical use is a sealed product that charges through a plastic case with no exposed contacts.

• 15+ years of electronic components experience
• Secure ordering process
• Excellent customer feedback
• Confirmed delivery dates
• Competitive pricing on volume orders
• Global export experience with responsive after-sales support

Other product types we regularly stock and supply appear below.