Need help with a 4-6 layer High Frequency PCB design

[[email protected]]

I am working on a PCB design for our test site, which contains 100pads
and more than ten RF circuits with more than 50 RF I/Os. We have 12
types of VDD and two types of GND on this chip. I am thinking about
using a 6 layer board, signal, GND1, VDD, VDD, GND2, signal. However it
will be very hard to assign the layer for VDDs and to route VDD lines.
This board isfor a RF chip, so that transmission lines need to be
created by the signal layer and GND layer. Please give me some advices
on how many layer board I should design and what each layers are for.
And will it be possible to run PSpice simulations for it after the
design is done? Thanks.

Allen

 

[Mikkel Lund]

[email protected] skrev:

I am working on a PCB design for our test site, which contains 100pads
and more than ten RF circuits with more than 50 RF I/Os. We have 12
types of VDD and two types of GND on this chip. I am thinking about
using a 6 layer board, signal, GND1, VDD, VDD, GND2, signal. However it
will be very hard to assign the layer for VDDs and to route VDD lines.
This board isfor a RF chip, so that transmission lines need to be
created by the signal layer and GND layer. Please give me some advices
on how many layer board I should design and what each layers are for.
And will it be possible to run PSpice simulations for it after the
design is done? Thanks.

Allen

Hi Allen

Talk to your PCB manufacture. They can advise on the question you and
tell you the price of the varied layered boards.

 

[[email protected]]

[email protected] skrev:



Talk to your PCB manufacture. They can advise on the question you and
tell you the price of the varied layered boards.

Hi Hilsen,

Thanks for your answer. I've just contacted the PCB manufacture, but
they don't give any advices on the design issues.

Allen

 

[John Larkin]

I am working on a PCB design for our test site, which contains 100pads
and more than ten RF circuits with more than 50 RF I/Os. We have 12
types of VDD and two types of GND on this chip. I am thinking about
using a 6 layer board, signal, GND1, VDD, VDD, GND2, signal. However it
will be very hard to assign the layer for VDDs and to route VDD lines.
This board isfor a RF chip, so that transmission lines need to be
created by the signal layer and GND layer. Please give me some advices
on how many layer board I should design and what each layers are for.
And will it be possible to run PSpice simulations for it after the
design is done? Thanks.

Allen

Why have two different grounds? Why so many supplies?

What's the frequency range?

John

 

[Allen]

What's the frequency range?

John

Hi John,

There are RF circuits on the chip, such as LNA and PLL, which work at
about 5GHz. To be able to power on and off each individual circuit to
avid possible problems, such as oscillation, we have one power supply
for each circuit. This is the reason for having so many power supplies.
Any suggestions? Do you think that a four-layer PCB will be proper to
realize the functions? Thanks.

Allen

 

[maxfoo]

Hi John,

There are RF circuits on the chip, such as LNA and PLL, which work at
about 5GHz. To be able to power on and off each individual circuit to
avid possible problems, such as oscillation, we have one power supply
for each circuit. This is the reason for having so many power supplies.
Any suggestions? Do you think that a four-layer PCB will be proper to
realize the functions? Thanks.

Allen

5GHz, eh!? you'll need a 4-layer laminated stack-up. Use 1/2 oz copper,
Rogers 4350 on top and bottom and 2 layers of 4403 in the center.
Most RF chip companies have very detailed layout guidelines on their website.
Did you check their first?

 

[Allen]

Rogers 4350 on top and bottom and 2 layers of 4403 in the center.
Most RF chip companies have very detailed layout guidelines on their website.
Did you check their first?- Hide quoted text -- Show quoted text -

Hi,
I've let the "Advanced Circuits" fabricated our PCB once before, they
only have FR4, FR406, and IS410 for the boards, which have 1 to 8
layers. There is no guidelines on their website. Can you please refer
me some good PCB companies and websites? Also, does Rogers 4350 have
better high frequency performance than FR4 do? Why? Thanks.

Allen