LMX8410L: What is the definition of pin 34.

Hui Chen

Part Number: LMX8410L

Hi Support team.

I use LMX8410L in my new design, when I studied the datasheet, I found a confusion about the definition of pin 34.

In the section Pin Configuration and Functions , the top view diagram shows pin 34 is "NC", but the table followed named pin 34 as "GND".

Please help double check which is correct? How could I treat this pin when I draw the schematic?

Regards

Chenhui

over 4 years ago

0 Dean Banerjee over 4 years ago

TI__Mastermind 27691 points

Chenhui,

On the datasheet, which should be the final authority, this is NC.

On the EVM, it looks grounded through a resistor.

So the safest thing to do is ground this.

Regards,
Dean

0 Hui Chen over 4 years ago in reply to Dean Banerjee

Intellectual 430 points

Thanks for your reply. there are still some questions about it.

Which EVM file do you refer to. I just downloaded file snau225a on the production website page, but it looks there is no pin number in this schematic. So I don't know which one is pin34.

screen snapshot from snau225a:

Furthermore, I got another schematic of EVM form here:https://e2e.ti.com/support/rf-microwave/f/220/p/732808/2706300?tisearch=e2e-sitesearch&keymatch=LMX8410LEVM#2706300

https://e2e.ti.com/cfs-file/__key/communityserver-discussions-components-files/220/LMX8410LEVM.zip

In this design file, although two of them connected to 2 resistors, the other pin of the resistor just connected to a test point, so in fact, there NC pins are all floating,

I am confused by these two design , please kindly help double check which is correct? Can you give me a formal EVM schematic withou any mistake?

Regards

Chen

0 Dean Banerjee over 3 years ago in reply to Hui Chen

TI__Mastermind 27691 points

Chen

What I think is going on is that this pin was actually a test pin for design purposes. But we don’t disclose this functionality in the Datasheet and it is powered down. It likely doesn’t matter if it is grounded or NC, but we want to make a consistent comment what to do. Older legacy versions might still show the pin

0 Dean Banerjee over 3 years ago in reply to Dean Banerjee

TI__Mastermind 27691 points

Chen,

Before the LMX8410L was released, there were some earlier versions of this device with very similar pinout. On the earlier version of this device, Pin 34 was an ATP test point. I think the legacy of supporting this is why this pin was not grounded on the EVM.

Regards,
Dean

RF & microwave

RF & microwave forum

LMX8410L: What is the definition of pin 34.