CDCE913: Power supply recommendations of VDD and VDDOUT

Masanori Tachibana

Part Number: CDCE913

Hello support team,

I have some questions about CDCE913.
There is following description in the section "10 Power Supply Recommendations" in the data sheet.

There is no restriction on the power-up sequence. In case the VDDOUT is applied first, TI recommends grounding VDD.
In case the VDDOUT is powered while VDD is floating, there is a risk of high current flowing on the VDDOUT.

Question 1
How high is the current flowing while the VDD is floating state?
Is there a risk of mulfunction or breakdown of the device if high current flows?

Question 2
In case the VDD is connected to GND so that high current does not flow, is it OK to connect to GND through a resistor?
In that case, how much resistance be acceptable?

Best regards,
M. Tachibana

over 7 years ago

0 Puneet Sareen over 7 years ago

TI__Expert 8865 points

Hello Masanori,

Below are the answers:
Question 1
How high is the current flowing while the VDD is floating state?
Is there a risk of mulfunction or breakdown of the device if high current flows?
A: If the VDD is floating, output drivers & pre-drivers may draw high current which can be much higher than the reliability limits and may cause device damage.

Question 2
In case the VDD is connected to GND so that high current does not flow, is it OK to connect to GND through a resistor?
In that case, how much resistance be acceptable?
A: You can use 1K resistor.

Best regards
Puneet

0 Masanori Tachibana over 7 years ago in reply to Puneet Sareen

Genius 5350 points

Hello Puneet-san,

Thank you for the clear answer.
It was very helpful for me.

Kind regards,
M. Tachibana

0 Masanori Tachibana over 7 years ago in reply to Masanori Tachibana

Genius 5350 points

Hello Puneet-san,

I have some more questions about CDCE913.

1. What signal is output if CDCE913 starts up with no EEPROM written at all?
2. In case setting is completed and the clock is being outputted, what signal is output while setting is being changed again with I2C ?
I think that it will maintain the output signal which is set before, until the setting is completed. Is my understanding correct?

Best regards,
M. Tachibana

0 Puneet Sareen over 7 years ago in reply to Masanori Tachibana

TI__Expert 8865 points

Hello

A1: Please refer to the device default configuration:

A2: Once a byte has been sent, it is written into the internal register and is effective immediately.

Best regards

Puneet

0 Masanori Tachibana over 7 years ago in reply to Puneet Sareen

Genius 5350 points

Hello Puneet-san,

Thank you for your advice.
It was very helpful for me.

Best regards,
M. Tachibana

Clock & timing

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CDCE913: Power supply recommendations of VDD and VDDOUT