LM25119 has no output

苏正武

LM25119 has no output [Copy link]

 

I downloaded the schematic and PCB directly from TI's official website. I also used the official four-layer board data to make the sample. I wanted to test the sample first to see how it works, but there was no output. I couldn't find out what the problem was. R1/R2/C6 was not soldered. I replaced the MOS with an 85A one. The other components are the same as the schematic diagram. There is no waveform when measuring the RT pin. Has anyone used it before? Can you help me see what the problem is?

qwqwqw2088

There is no waveform on the RT pin either.

This means that the internal oscillator has no clock signal and the chip does not work.

Continue to check whether the parameters of surrounding devices are assembled correctly and whether the chip itself is soldered.

rch

Very heavy is really good

maychang

"R1/R2/C6 not soldered"

Without R1, VCC1, VCC2, HB1, and HB2 will have no power.

苏正武

maychang posted on 2019-10-22 14:48 "R1/R2/C6 are not soldered" Without R1, VCC1, VCC2, HB1, and HB2 will have no power.

Which pins need to have voltage?

苏正武

qwqwqw2088 posted on 2019-10-22 14:46 There is no waveform on the RT pin, which means that the internal oscillator has no clock signal, and the chip does not work. Continue to check whether the parameters of the surrounding devices are assembled correctly...

The component parameters are correct, no problem.

maychang

Su Zhengwu posted on 2019-10-22 14:54 Which pins need to have voltage? ?

"Which pins need to have voltage?"

Look at the datasheet, there must be an explanation.

okhxyyo

Has the landlord's problem been solved?

苏正武

okhxyyo posted on 2019-10-24 13:54 Has the original poster's problem been solved?

The problem has been solved, but the current is not as high as the official said, and the heat dissipation cannot be achieved.

alan000345

The large current that the official said is difficult to achieve, and it is too large. Will it affect the service life?