LDC1612 External master clock frequency

Hidetoshi Matsunami

Expert 2750 points

Other Parts Discussed in Thread: LDC1612

Hello Team,

I'd like to ask you about External clock frequency for LDC1612.

I think I can supply 7.5M ~ 40Mhz to CLKIN as master clock the following condition.

Is my understanding correct?

- Target Distance: 2cm

- Resolution: 30um

- Diameter of Target: 2cm

- Capacitance: 17.4pF

- inductance: 25.9uH

- Free Field requency: 7.5MHz (f=1/(2π √LC)=around 7.5MHz)

- Target Material: Copper

Best Regards,

Hidetoshi Matsunami

over 9 years ago

0 Chris Oberhauser66 over 9 years ago

TI__Genius 14270 points

Hello Hidetoshi-san,

The LDC sample rate for a given measurement resolution is proportional to the reference frequency, so using a maximum reference frequency (40MHz) is recommended.

In addition, it is recommended to maintain the ratio 4*fsensor < freference.

Regards,

ChrisO

0 Suhas Raja Chandragupta55 over 9 years ago

TI__Intellectual 1690 points

Hello Hidetoshi-san,

It is recommended to have higher capacitance than the value you have mentioned. Please have a look at the following blog post.

https://e2e.ti.com/blogs_/b/analogwire/archive/2014/11/21/inductive-sensing-sensor-frequency-constraints

Please let me know if you have any questions.

-Best Regards,

Suhas

0 Hidetoshi Matsunami over 9 years ago in reply to Chris Oberhauser66

Expert 2750 points

Hello Chris,

I appreciate your support.

I understood it.

Best Regards,

Hidetoshi Matsunami

0 Chris Oberhauser66 over 9 years ago in reply to Hidetoshi Matsunami

TI__Genius 14270 points

Hi Hidetoshi-san,

Glad to help.

regards,

ChrisO

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LDC1612 External master clock frequency