CD74HC4017-Q1: tpd vs CL

Atsushi Hirai

Expert 3820 points

Part Number: CD74HC4017-Q1

Hi team,

The datasheet has tpd spec with CL=50pF and 15pF as the condition. There are 2 questions.

Do you have tpd vs CL characterization plot data?
Is tpd directly affected by CL? or longer tr/tf causes longer tpd?(rising edge start point of output is delayed or just longer tr due to higher RC constant)

Best Regards,

over 2 years ago

+1 Sebastian Muriel over 2 years ago

TI__Genius 14210 points

Hi Hirai-san,

Atsushi Hirai said:
Do you have tpd vs CL characterization plot data?

We do not have tpd vs C_L characterization plot data.

Atsushi Hirai said:
Is tpd directly affected by CL?

Yes tpd is directly affected by C_L .

Atsushi Hirai said:
or longer tr/tf causes longer tpd?

Yes. Below is a plot of the Tpd vs CL using the data sheet values tested at 15pF and 50pF. At 0 load there is internal delay.

Regards,

Sebastian

0 Atsushi Hirai over 2 years ago in reply to Sebastian Muriel

TI__Expert 3820 points

Sebastian-san,

Thanks! I talked with my customer.

He is going to use this device with Vcc=3.3V. But above approximation is for Vcc=5V and, Datasheet doesn't have Vcc=3.3V typical value for both 15pF and 50pF.

Could you provide the typical value to make similar approximation for Vcc=3.3V?

Best Regards,

+1 Clemens Ladisch over 2 years ago in reply to Atsushi Hirai

Guru 256820 points

3.3 V values are not specified for HC family devices. You have to use linear interpolation: [FAQ] What method is best used for estimating specification values between those given in the datasheet?

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CD74HC4017-Q1: tpd vs CL