LMX2430: Ftest/LD output pin operates as an open-drain output depending on the MUX[3:0] setting

Hi Conor,

What is their MUX setting? This part has been out for the market for more than 20 years, I am pretty sure that a pull-up resistor is required for open drain analog LD. 

Hi Noel,

Sorry, I didn't include the register setting information. Currently, MUX[3:0] is set to 0101.

Despite being set as open-drain output as shown above, a high voltage is being output without an external pull-up resistor. So I would like to know whether Ftest/LDpin is internally pulled up when set to open-drain. The same question has been posted in "Related Questions" but it has not been resolved, so I would like a clear answer.

Thanks,

Conor

Hi Conor,

I have a LMX2433 EVM, let me check in the lab.

Hi Noel,

We look forward to hearing your experiment results.

Thanks,

Conor

Hi Noel,

I couldn't see the image you attached. Could you please repost it?
Are you planning on updating the datasheet again?

Thanks,

Conor

Hi Noel,

In the image, the corrected column is 0100, not 0101.

Am I correct in understanding that 0101 also means push-pull output?

Please clarify what updates are planned for the datasheet.

Thanks,

Conor

Hi Conor,

There is no IF VCO on the board, I tested RF LD only.

I strongly believe that the same datasheet error applies to IF as well. 

Datasheet change involves a long process, if you need an update datasheet, I can generate one to you. However, it will has watermark on it as it is not an officially released datasheet.

Hi Noel,

Noel Fung said:

Datasheet change involves a long process, if you need an update datasheet, I can generate one to you. However, it will has watermark on it as it is not an officially released datasheet.

Thanks for confirming.
Please provide a draft of the LMX2430 datasheet that explains the appropriate IF pin functions.

Thanks,

Conor

Hi Conor,

OK, will make a draft in this week.

Hi Noel,

OK, Looking forward to hearing from you.

Thanks,

Conor