LT3651 overheating

Hi there,

I'm using LT3651 to charge 8.4V 8300mA Li-ion batteries @4A or 2A

Problem is that the chip is overheating too much, it will be extremely hot!  over 120 °C  

Below is my schematic design and connections.

Even if I reduce the charge current to 2A still it will be heat up too much 

Please help to find the problem.

Thank you.

  • 0
    •  Analog Employees 
    on May 11, 2020 6:03 PM 8 months ago

    Hi Ehsan,

    LT3651 is a monolithic buck battery charger which passes all power through it. This heating is normal to an extent, but can be improved with a layout that helps to dissipate the heat. Make sure you have vias underneath the IC going to a GND plane to help sink heat.

    To characterize how much heating you should expect, calculate the power loss through the device and compare that against the thermal characteristics given in the datasheet (we put these right below the pinout diagram on page 2).