LM567C: Frequency Detection Delay

Hideki Hayashi1

Part Number: LM567C

Hi team,

Regarding Figure 13 in the datasheet, there is a delay from the timing which input frequency becomes inside a selectable range.

I think the delay depends on the loop filter at pin 2. How can customer estimate the time of this delay?

Regards,

Hideki

over 4 years ago

0 Lane Boyd over 4 years ago

TI__Genius 16845 points

Hi Hideki,

You could estimate the delay using Figure 9

Kind regards,
Lane

0 Hideki Hayashi1 over 4 years ago in reply to Lane Boyd

TI__Expert 8490 points

Hi Lane,

From my understanding, bandwidth, X-axis, is set by C2 (actually C2 value is determined by desired bandwidth) and cycle, Y-axis, which is needed to transit from H to L or L to H is within the two bars.

So, choosing 10% as an example, delay which needed to transit will be from 15 to 40. And it can be converted in units of time, it will be 15/f0 to 40/f0, where f0 is input frequency. If input frequency is about 300kHz, the delay will be about 50 us to 166 us.

Is my understanding correct?

Regards,

Hideki

0 Lane Boyd over 4 years ago in reply to Hideki Hayashi1

TI__Genius 16845 points

Hi Hideki,

I agree, your understanding is correct.

Kind regards,
Lane

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LM567C: Frequency Detection Delay