LMT84-7 Eval Board layout

Jonathan Bonnevie

Other Parts Discussed in Thread: LMT87, LMT86, LMT85

Hello,

I have 2 questions regarding the PCB layout of the LMT84-7 Eval Board:

Why is there a zero-ohm resistor between the VDD pin 5 and other VDD pins for LMT85, LMT86 and LMT87 devices ?
What is the use of the C5 capacitor ? Are bypass capacitors C2, C4, C7 and C9 not sufficient ?

Many thanks and best regards,

Jonathan.

0 Aaron Heng over 10 years ago

Hi Jonathan,

I will get back to you soon.

Aaron

0 Aaron Heng over 10 years ago in reply to Aaron Heng

Hi Jonathan,

I'm sorry for the long delay. Please see my comments below.

1. Why is there a zero-ohm resistor between the VDD pin 5 and other VDD pins for LMT85, LMT86 and LMT87 devices ?

The zero-ohm resistors are just a placeholder for low pass filter in case if you need to connect the board with a long cable where there is a noisy environment.

2. What is the use of the C5 capacitor ? Are bypass capacitors C2, C4, C7 and C9 not sufficient ?

Again C5 is just a placeholder, and it shouldn't be populated. I think I forgot to note "DNP" on the BOM.

Aaron

0 Jonathan Bonnevie over 10 years ago in reply to Aaron Heng

Aaron,

Thank you for your answer.

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