CYBLE-416045-EVAL VDD 5.0V instead of 1.8V

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GuNo_288966
Level 4
Level 4
25 replies posted 10 replies posted 10 questions asked

Hi,

I have a CYBLE-416045-EVAL board. According to the schematics, the voltage for the PSoC6 BLE module can be adjusted by setting or removing the jumper J2.

The documentation says: jumper short => 3.3V, jumper open => 1.8V.

I have verified that with the datasheet of the TPS735 voltage regulator, everything looks ok.

However, what I observe is:

jumper short => VDD=3,3V (measured between TP3 and TP2)

jumper open => VDD jumps up to 5V! This is out of specs for the CYBLE-416045-02 module.

I have then measured the voltage at the FB pin (pin 2) of the voltage regulator.

Jumper short => 1.220V (close enough  to 1.208V, ok)

jumper open => voltage goes up to 2.44V (FAIL), should stay at 1.208V.

It seems that the voltage regulation of the TPS73 fails.

I have looked at all resistors and capacitors, everything looks like it should be according to the schematics.

What is wrong, what should be changed to set VDD to 1.8V?

Update: It seems that the problem only occurs when the jumper J2 is pulled while the board is powered.

Regards,

Guenter

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1 Solution
VenkataD_41
Moderator
Moderator
Moderator
750 replies posted 500 replies posted 250 solutions authored

Hi Guenter,

We would like to say that it is not recommended to pull the jumper when the regulator is powered. This may cause the IC to go unstable state and that might be the reason for this behavior.

However, please create a thread in Texas Instruments forum page to get exact answer to your query.

Search - TI E2E support forums

Thank you for pointing this issue to us.

Best regards

Ganesh

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1 Reply
VenkataD_41
Moderator
Moderator
Moderator
750 replies posted 500 replies posted 250 solutions authored

Hi Guenter,

We would like to say that it is not recommended to pull the jumper when the regulator is powered. This may cause the IC to go unstable state and that might be the reason for this behavior.

However, please create a thread in Texas Instruments forum page to get exact answer to your query.

Search - TI E2E support forums

Thank you for pointing this issue to us.

Best regards

Ganesh

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