TIDA-01486: Overheating design - need clarification

M.A.M

Part Number: TIDA-01486
Other Parts Discussed in Thread: THS3095

Hi,

My customer just received their newly built TIDA-01486 AFE board and smelled 'hot components'.

When large signals pass the RX portion, the 10ohm resistors R39-R42 may source up to an Ampere into the protective diodes, and the amplifier THS3095 gets blazing hot.

Question: - Why are R39-R42 not 100ohm or larger? Was it a typo and should have been 10kohm instead?

We cannot get our heads around the selection criteria of 10ohms in those positions.

Please clarify a.s.a.p.

Thanks.

B.r M.A.M

over 3 years ago

0 Giovanni Campanella over 3 years ago

TI__Intellectual 1560 points

Hello,

We have not seen any overheating problem while performing tests with TIDA-01486. R39-R42 are 10 Ohms resistor. Simulations and tests have been performed with these resistors value and results can be seen from the simulation model and user guide.

What is the signal at the input of the THS3095?

Also what have you selected as a Vbias signal?

Thanks

Gio

0 M.A.M over 3 years ago in reply to Giovanni Campanella

TI__Expert 8455 points

Hi,

The signal over the trancducer is about 8Vpp.

It must be strong for a clamp-on spplication.

Vbias comes from MSP430FR6047EVM as 3.3V.

Why did you choose such a low resistor value before the diodes?

/M.A.M

0 Giovanni Campanella over 3 years ago in reply to M.A.M

TI__Intellectual 1560 points

Hello,

The low resistor value has been chosen based on the simulation model and confirmed during tests.

Nevertheless higher resistor values can be chosen.

Please let me know if you need further help.

Best regards

Gio

Simulation, hardware & system design tools

Simulation, hardware & system design tools forum

TIDA-01486: Overheating design - need clarification