LM5145: IC fever serious

Hi Raymond,

To reduce the no-load input current, use lower Qg MOSFETs and check the inductor ripple current (keep it < 35% to reduce core losses).

Regards,

Tim

By the way, you can tie the NC pins to GND for better heatsinking of the IC. No need for the zener on FB. Also, add a small cap at ILIM as recommended in the datasheet.

In terms of reducing NL current, also consider lower Fsw.

--

Tim

Hi Raymond,

Please send a completed quickstart calculator so I can review the design.

Regards,

Tim

Please include MOSFET and inductor part numbers as well. 35mA no-load input current sounds about right, so it seems you're on the right track here.

Hi Raymond,

The MOSFET looks okay, it's a good low-side FET. However, if D < 50%, you can use a higher Rdson, lower Qg device for the high-side FET. This will reduce switching and gate drive losses and decrease the no-load input current.

Regards,

Tim