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ADC input resistance

per239955_st
Associate II
Posted on January 02, 2006 at 10:58

ADC input resistance

3 REPLIES 3
per239955_st
Associate II
Posted on January 02, 2006 at 10:11

Hi,

I would verify that I've understood the reference manual correctly.

At page 336 it says that the input resistamce of an ADC input (in round robin mode) is:

3000 [kOhm][MHz] /fmod

In my application PCLK2 is 32MHz and the prescaling factor set to 500.

According to my calculations the input resistance is 47kOhm.

Is this correct?

hichem2
Associate II
Posted on January 02, 2006 at 10:44

Hi Beach,

As you said the constant K is equal to 3000 [kOhm][MHz]

by the way the input resistance is 47MOhm not kOhm.

With best regards,

Hichem ;)

per239955_st
Associate II
Posted on January 02, 2006 at 10:58

Aaahhh...

47MOhm was a 'better' value (my fault).

That makes it possible to use a lower prescaling factor without getting a redicoulisy low input resistance value. ;)

Thanx