Regarding the PCB layout requirements

Hi Tsukada 

Thank you for reaching out to the team.

I would like to ask several items below to understand the design requirements and applications better.

• What are the intended end applications? Signal conditioning, measurements, etc..
• What are the target supplies for this part? Do you intend to use a single or dual supply configuration?
• What are the desired input signal and input levels for AD8228? Is this purely DC, or does it need a differential signal?

Regarding your questions:

Typically, I use these guidelines for board layouts:

• Input pins: trace widths are 10 mills (~250um)
• Supply pins:  min trace widths are 20 mills (~500um), depending on the power consumption; it can go as high as 40mills (~1000um)
• Output should be wider than Input pins as to eliminate parasitic resistance.
• For low-power applications, 500um is enough.
• You might consider REF pins as supply pins if you use a source to offset your output levels.
• Please look at pages 17 to 18 of the DS for additional layout considerations for this part. AD8228 Low Gain Drift Precision Instrumentation Amplifier Data Sheet (Rev. 0) (analog.com)

 I hope this suggestion will help you.

Regards,

Hi Arsol-san,

Your answers solved the problem I'm facing now. Also, Thank you for giving me a good perspective in the first half.

Since we were referring to a circuit diagram created by the customer, we did not know the exact method of use. Next time, I will ask the customer for more details.

On the other hand, there were some words that I did not understand well. Does "single or dual supply configuration" refer to the conditions for applying voltage to +Vs/-Vs? In actual application, +Vs/-Vs=+15V/-15V.

The -IN/+IN and Vout will have a trace length of 100mm to 200mm, but if you have any concerns regarding this, it would be helpful if you could give us some advice.

Thanks,

Hi Tsukada 

Correct, the dual supply configuration has a symmetrical (same absolute value) voltage being forced on +Vs and -Vs. This case is +/-15V.

Regards,

Hi Arsol-san,

Thank you for the clarification.

Please let me know if you have any advice the following point.

>The -IN/+IN and Vout will have a trace length of 100mm to 200mm, but if you have any concerns regarding this, it would be helpful if you could give us some advice.

Thanks,

Hi Tsukada -San,

The shorter the trace length from Input pins to a connector or source is better. To eliminate parasistics (line capacitance, impedance, etc..) that will have an effect to your signal integrity and possible voltage drop.

Regards.