CD4046B: Frequency Capture Range (2Fc) discrepancy in equation

Renan Santos Adriano

Part Number: CD4046B

Hi Team,

My Customer wanted to know which equation for Frequency Capture Range (2Fc) is correct or why the datasheet vs application note equation is different? From the datasheet of CD4046B (page 3-125) equation for 2fc is having a multiplier of 1/pi, unfortuanately application note states that the equation is the same except that the multiplier is 1/(tau1) (on page 15).

Datasheet (blue pen)

vs Application note (yellow).

Application Note: http://www.ti.com/lit/an/scha002a/scha002a.pdf

Datasheet: https://www.ti.com/lit/ds/symlink/cd4046b.pdf

Looking forward to your reply.

Best regards,

Renan Adriano

over 7 years ago

0 Emrys Maier over 7 years ago

TI__Guru* 97666 points

Hi Renan,

The CD4046B datasheet is the one I would go off of. The text in that document is scanned in (since the part is at least 40 years old), whereas the text in the app note appears to have gone through an OCR engine. The OCR most likely saw "π" as "τ1"

I'll mark this in our errata to fix.

0 Renan Santos Adriano over 7 years ago in reply to Emrys Maier

TI__Mastermind 26015 points

Hi Emrys,

Thank you for this reply, appreciate it a lot

Regards,

Renan

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CD4046B: Frequency Capture Range (2Fc) discrepancy in equation