MP6650 doesnt working

I bought MP6650 ic and want to drive computer fan.

The number on the ic is |BGJM. Order code, is MP6650GJL-0000-Z but I am not sure pin out is L or R side. I solder the ic as it is L.

The ic is not working.

On pwm pin, I am measuring 3.8 volt without making any connection? is it normal?

How can I be sure the ic is L or R side.

I am measuring zero voltage on out1 and out2.

Hi zefir,

Thanks for your question.
Please provide a diagram of how you are connecting the part and the voltage on each input (VCC, FG/RD, PWM), as well as everything you are measuring on the outputs.
Are you measuring 3.8V without even applying VCC?

Thanks,
Cindy

I am adding the design of the fan side.

the input is 24 volt and then it is regulated to 5 volt with TI LDO. I measured it and I am getting exactly 5 volt.

C23 is the capacitor of the voltage in pin. I put 10 uF. also I checked 2.2 uF too.

R16 is the pwm resistor. I put 50 ohm first. (from your datasheet) But the ldo got very hot. Then I tried 45-50 kohm. nothing changed. Also I tried without resistor.

without making any connection to pwm line. I gave power. the fan started to spin a couple turns and stopped. waiting a while and the fan started spinning a couple of turns and stopped.

after this attempt, I make connection of pwm line. nothing changed.

monolithic

Hi Zefir,

Apologies for the delayed response.
Do you have a more clear schematic? It’s difficult to decipher how you are connecting the part from the board layout. Could you also provide scope captures of VCC, PWM, OUT1 and OUT2?

Thanks,
Cindy