Influence of amplitude setting in LDC1000

Gerardo Vanoni

Hello,

as known, the oscillation amplitude can be set to either 1V, 2V or 4V (Addr.0x04, Bit Field 4:3).

By now, I did not find any hint on what value sholud be chosen for the amplitude or in what case to use one or the other value.
When should I choose one amplitude instead of another? What is the idea behind choosing one or the other value? What are the corresponding criteria? Application note? Influence on behaviour of LDC1000?

Best regards,

Gerardo

over 10 years ago

0 Sunny Qin over 10 years ago

TI__Expert 4890 points

Hi,

High amplitude is good for sensitivity and noise, but it will need more power.

Regards, Sunny

0 Benjamin Sprague over 9 years ago in reply to Sunny Qin

Prodigy 210 points

Do you have typical power requirements for different amplitude values? I noticed the datasheet only shows supply current without the LC tank. It would be nice to know total current draw for the part.

0 Don Liu over 9 years ago in reply to Benjamin Sprague

TI__Intellectual 1290 points

Hi,

The maximum tank driving current is 2mA, so the power consumption is limited by it.

Lower amplitude as the advantage of emitting lower EMI. If you experience EMI compliance problem, it offers an easy way for EMI reduction. Each step down of amplitude reduced EMI by 6dB.

Don

0 Evgeny Fomin over 9 years ago in reply to Don Liu

TI__Genius 9300 points

Let me add that knowing Rp value, as measured by LDC1000, and the setting for Vpp, you can calculate the current that goes into tank as <I> ≈ Vpp/2/sqrt(2)/Rp

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Influence of amplitude setting in LDC1000