OPA855DSGEVM: Gerber file issues

Markus Polster

Hey there,
I am about to design an OPAmp TIA board with the OPA8551. I have found the gerber files here and a wanted to double-check my own design with them.

Unfortunately, I do not quite understand on which copper layers the +V and the -V rails are wired. The gerber files do not make sense to me. The Opa Pins do not have any wires to VCC or VSS. Pin9 shows only 2 vias with no further wiring...

We are also not really sure what to do with the GND-layer. This one is nearly empty, and the few small fills are not connected, they are floating...

How do I solve this?

My first attempt was not sucessful, the circuit oscillated. I suppose that a GND-plane underneath the OPA hat too much capacitance...

Thanks in advance,

Markus

over 2 years ago

+1 Jacob Freet over 2 years ago

TI__Expert 8720 points

Hi Markus,

If you refer to the PCB layers in the users guide: https://www.ti.com/lit/ug/sbou210/sbou210.pdf, the ground and power layers are negatives. That means they colored areas represent voids and all the white areas are copper. The ground and power planes are mostly solid copper except for areas cut out underneath pins that are sensitive to capacitance. The power plane is split with VEE on the bottom half and VEE on the top half.

Let me know if you have any other questions.

Best,

Jacob

0 Markus Polster over 2 years ago in reply to Jacob Freet

Prodigy 60 points

Hello Jacob,
thank you for the reply. That helped a lot.

Regards,
Markus

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OPA855DSGEVM: Gerber file issues