TPS40009: TPS40009DGQR output is Abnormal

Jerry Yang48

Part Number: TPS40009
Other Parts Discussed in Thread: TPSM82480, TPS62480,

Hi :

When customers use TPS40009DGQR, Vin is 3.3V, output is 1.0-1.1V, current value is 4.5A. But after mass production, customers found that the PIN8 output voltage of the chip was 0, but it would be better to replace a chip. Through the test comparison, the resistance between PIN8 and PIN5 (GND) with output of 0 is 31.7 ohms. The resistance between PIN8 and PIN5 (GND) with normal output is 31.7 ohms. There is no abnormality. Please look at the schematic. What's the problem? Thank you very much.

over 5 years ago

0 Dorian Brillet de Cande over 5 years ago

TI__Genius 14876 points

Hello Jerry,

I will come back to you tomorrow on the schematic.

Could you provide the SW pin waveform ?

Thank you very much!

Best Regards,

Dorian

0 Dorian Brillet de Cande over 5 years ago in reply to Dorian Brillet de Cande

TI__Genius 14876 points

Hello Jerry,

Were the mass production boards ever functional or were they not functional at time 0?

To help you debug your system, could you provide the following:

- Waveforms of the SW pin

- PCB layout

- Part numbers of the BOM

I also recommend you have a look at the newer solution, easier to implement, TPSM82480 module and TPS62480 buck-converter. Which can be a really good fit for customer application.

Thank you very much!

Best Regards,

Dorian

0 Dorian Brillet de Cande over 5 years ago in reply to Dorian Brillet de Cande

TI__Genius 14876 points

Hello Jerry,

I haven't heard back from you.

Were you able to gather the information from my previous message?

Thank you very much!

Best Regards,

Dorian

0 Jerry Yang48 over 5 years ago in reply to Dorian Brillet de Cande

Intellectual 640 points

Hi Dorian:

At present, customers have been mass-produced for several years, so it is impossible to follow the change number for the time being.

These days I am traveling abroad. This Friday I will go to the customer to test the waveform of SW pin. Do you have any other pin waveform to test?

0 Dorian Brillet de Cande over 5 years ago in reply to Jerry Yang48

TI__Genius 14876 points

Hello Jerry,

Yes, the more information the better. Could you provide the following:

- Startup Waveform, (VIN&VSS& VOUT) like figure 9 in the EVM user's guide

- Waveform of V_HDRV & V_LDRV at startup and "steady state". Figure 7 in datasheet.

- Waveform of the SW pin

- If possible I_coil, current in the inductor

- Can you verify the voltage at FB?

Thank you very much!

Best Regards,

Dorian

0 Dorian Brillet de Cande over 5 years ago in reply to Dorian Brillet de Cande

TI__Genius 14876 points

Hello Jerry,

Can you give me some feedback on what was the problem the customer was facing here?

Thank you very much!

Best Regards,
Dorian

0 Jerry Yang48 over 5 years ago in reply to Dorian Brillet de Cande

Intellectual 640 points

Hi Dorian:

We find somewhere short circuit in Capacitance. Not the fault of tps40009, Now the tps40009

is working normally,Thanks you !

0 Dorian Brillet de Cande over 5 years ago in reply to Jerry Yang48

TI__Genius 14876 points

Hi Jerry,

Thank you for the feedback!

Regards,

Dorian

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TPS40009: TPS40009DGQR output is Abnormal