Clock driving Capacitive Load

Bhavdipsinh Rathod

Expert 2225 points

Other Parts Discussed in Thread: LM741, LM324

Hi Experts,

Any one explain the term Capacitive Load in terms of signal driving capacity.

I need to generate 40 MHz and 4 KHz signal with 400 pF and 120 pF capacitive load respectively.

I want to understand the need to source required current to drive it.

Regards

Bhavdipsinh

over 10 years ago

0 Arvind Sridhar over 10 years ago

TI__Mastermind 24205 points

Hi Bhavdipsinh,

In general, for the cases where you are driving a lumped capacitive load 'C', I = C dV/dt where C is the lumped capacitive load, dV = 60% of 3.3V (for a 3.3V LVCMOS output), dt is the rise time of the signal and I is the short circuit current of the output.

Regards

Arvind Sridhar

0 Bhavdipsinh Rathod over 10 years ago in reply to Arvind Sridhar

Expert 2225 points

Hi Arvind,

Thanks for your explanation which help lots.

i would like to share my requirement to get right solution from TI (you).

I need to generate Clock signal with +13V, -9V voltage level ( I will use controller to generate PWM and then voltage shifter using MOSFET or OPAM.

I have to deliver this clock on detector PIN which required 120 pF capacitive load.
Clock frequency will be 4 KHz.

So, How much current I have to deliver to drive clock of that detector?

Thanks

Bhavdipsinh

0 Arvind Sridhar over 10 years ago in reply to Bhavdipsinh Rathod

TI__Mastermind 24205 points

Hi Bhavdipsinh,

Do you have a TI device in mind so that I can redirect your query to the appropriate product line? The Clock and Timing group does not have any parts in its portfolio that can support what you are trying to do here.

Regards

Arvind Sridhar

0 Bhavdipsinh Rathod over 10 years ago in reply to Arvind Sridhar

Expert 2225 points

Hi Arvind,

Controller may be in DSP (picolo of delfino series) for PWM gneration.

At Analog part Its groud level workout so need help from TI experts. ( we are suing LM741, LM324 for Level shifting in simulation part)
Thanks & regards
Bhavdipsinh

0 Arvind Sridhar over 10 years ago in reply to Bhavdipsinh Rathod

TI__Mastermind 24205 points

Please post your query on the Precision Amplifiers Forum

Regards
Arvind Sridhar

0 Bhavdipsinh Rathod over 10 years ago in reply to Arvind Sridhar

Expert 2225 points

Will you do It?

I dont know how to redirect this to Precision Amplifiers.
Thanks

0 Arvind Sridhar over 10 years ago in reply to Bhavdipsinh Rathod

TI__Mastermind 24205 points

Please post on e2e.ti.com/.../

Regards
Arvind Sridhar

Clock & timing

Clock & timing forum

Clock driving Capacitive Load