ADS131E08EVM-PDK: MMB0 Board No Power LEDs On

Hi Emily Marcelo,

Can you try using a lower-voltage supply e.g. 9V, through the barrel jack connector (J2) on the MMB0? If not, try applying a +5V supply to the MMB0 directly using J14. When using an external bench supply to power J14, make sure to remove jumper J12, set the J13 jumpers, and apply the voltage to the correct pins on J14. This is shown in the image below

-Bryan

Hi Bryan,

I used a 9V supply through J2 and got the same problem as before. The same thing happened when using an external bench supply through J14 after removing J12 and setting the J13 jumpers. Using the bench supply, I am measuring about 0.109V at the +3.3V test points.

Is there anything else I should try?

Hi Emily Marcelo,

Where are you measuring the +3.3V voltage? Once you apply the bench supply to J14 you should be able to probe the J5 header on the MMB0 (with the E08 EVM daughter card removed) and measure 3.3, 1.8, and 5V as shown in the diagram below. Note that this diagram shows the jumper as J3 because this is taken from a different daughter card, not the MMB0.

If you use the external 5V supply and you are not seeing any voltage at these pins, then you might have a dead board

You can also send me a picture of your setup so I can see if anything is wrong

-Bryan

Hi Bryan,

I was previously using the point on J6 to measure +3.3V. Probing the J5 header on the MMB0, +5V and +1.8V appear properly. I still measure about 0.109V on the +3.3V pin of J5.

Here are images of my setup:

Hi Emily Marcelo,

It is interesting that the 5V works but the 3V3 does not. Below is a portion of the MMB0 schematic that shows where the 3V3 is generated. Can you probe on these pins with the MMB0 powered and see if the voltage is correct? Specifically, C41 and R15 should provide the 3V3 voltage.

If you don't get the correct voltage, then it is possible that the TPS70302 was damaged (you can probe on that 1.6V net as well to see if this LDO is completely non functional). You could try applying an external 3V3 voltage to one of those points near the LDO, or even to the J5 header

-Bryan

Hi Bryan,

Probing at the pins, I measured about 0.109V at the 3V3 and close to no voltage on the 1.6V net.

Supplying an external 5V and 3.3V resulted in all LEDs except for 1.6V lighting up. I'm guessing that 1.8V is generated from the 5V rail on a separate regulator while 3.3V and 1.6V both come from the TPS70302, which would explain why only the 1.6V stayed off. 

Looking at the image you sent, it looks like U5 regulates the input voltage from the J2 power jack down to 5V. I checked the input and output pins of U5 and they were shorted, so it's possible that the TPS70302 was damaged from overvoltage.

Hi Bryan,

Thank you for the help! If possible, I would like to have a replacement board sent.

Hi Emily Marcelo,

Ok, I will work to get this done. Can you provide me your email address? If you do not want to provide this information on the public e2e forum, you may send it to me via private message. You can do so by hovering over my name (Bryan Lizon86) and selecting "Request friendship". This allows us to send private messages

-Bryan

Hi Emily Marcelo,

One more comment: when you receive the new board, I would either use a lower voltage AC power adapter (<=9V), or use the J14 terminal block to power the MMB0. The REG104 has a thermal shutdown mode that can be triggered by excessive power dissipation when the difference between the input voltage and output voltage is large e.g. 12V --> 5V

-Bryan

Hi Bryan,

Thank you for the suggestion, I will most likely be using the J14 block to power the new board.

Sounds good Emily