Problem with 2 different supply voltages on PCB
Problem with 2 different supply voltages on PCB
(OP)
Hi everyone,
I have a 2 layer board with one GSM and one GPS module. The operation voltage is 3.7V and 3.3V for the GSM and GPS. Is there a problem for the two voltages to be on the same board?
The tracks are not very close to each other(4 cm at least) and the board thickness is 0.5mm. If the tracks are on different sides is it still a problem? Is the difference of the two voltages significant enough to cause crosstalk?
Thanks in advance!
I have a 2 layer board with one GSM and one GPS module. The operation voltage is 3.7V and 3.3V for the GSM and GPS. Is there a problem for the two voltages to be on the same board?
The tracks are not very close to each other(4 cm at least) and the board thickness is 0.5mm. If the tracks are on different sides is it still a problem? Is the difference of the two voltages significant enough to cause crosstalk?
Thanks in advance!





RE: Problem with 2 different supply voltages on PCB
Dan - Owner

http://www.Hi-TecDesigns.com
RE: Problem with 2 different supply voltages on PCB
Of course, whether or not the cross talk causes problems, depends on other design factors.
RE: Problem with 2 different supply voltages on PCB
RE: Problem with 2 different supply voltages on PCB
Dan - Owner

http://www.Hi-TecDesigns.com
RE: Problem with 2 different supply voltages on PCB
RE: Problem with 2 different supply voltages on PCB
Dan - Owner

http://www.Hi-TecDesigns.com
RE: Problem with 2 different supply voltages on PCB
RE: Problem with 2 different supply voltages on PCB
A 2-in square FR-4 board with 10 mil layer thickness presents about 400 pF of capacitance, assuming solid sheets of metallization, which would be shared across both adjacent layers. Nonetheless, the bypass capacitance on the victim layer must be in the hundreds of microfarads. The coupling ratio would be at worst 1:100?
TTFN
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RE: Problem with 2 different supply voltages on PCB
- Pay attention to clock track layout
- Add ferrite beads and ceramic caps to your PS input.
- While possible, set up both modules for minimal 'chatter', i.e. half duplex, etc.
RE: Problem with 2 different supply voltages on PCB