MSP430F149: For the Ad conversion sequence channel single conversion, the crosstalk of the channel issue

Cherry Zhou

Part Number: MSP430F149

Hi team,

Use P60 to P65 as the measurement channel. When P60 changes to a larger value, the P61 external analogue signal is a fixed value and the P61 value increases; when P65 changes to a larger value, the P61 external analogue signal is a fixed value and the value increases. The impact was around 0.5%

The customer would like to know why it would be impacted and if there is anyway to solve this problem.

Could you help check this case? Thanks.

Best Regards,

Cherry

over 4 years ago

0 Allen Gao over 4 years ago

TI__Expert 7080 points

Hi Cherry,

Could you provide the test data and the schematic?

0 Cherry Zhou over 4 years ago in reply to Allen Gao

TI__Mastermind 22235 points

Hi Allen,

The customer has checked this issue with their supporting team and found that this is a common issue. And the customer would like to know if TI has any better solution can decrease the impact of the crosstalk of the channel.

Thanks and Best Regards,

Cherry

0 Cherry Zhou over 4 years ago in reply to Cherry Zhou

TI__Mastermind 22235 points

Hi Allen,

May I know is there any updates?

Thanks and Best Regards,

Cherry

0 Allen Gao over 4 years ago in reply to Cherry Zhou

TI__Expert 7080 points

Hi Cherry,

I think the crosstalk is on customer layout not in the device. Let customer to test the input voltage of the P61 by a multimeter when other pin voltage is increasing.

0 Bruce McKenney over 4 years ago

Guru 100785 points

The easiest way to generate crosstalk is to set the sample/hold time (SHT0/1) too low, so the sampling capacitor doesn't have enough time to charge.

There is a formula in User Guide (SLAU049F) Fig 17-5 [hint: round up]. As a quick experiment, try setting SHT0 and/or SHT1 to something very large and see if the symptom changes.

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MSP430F149: For the Ad conversion sequence channel single conversion, the crosstalk of the channel issue