problem with op-amp loading input signal

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Jweaver
Level 3
Level 3
25 replies posted 10 sign-ins 5 sign-ins

Using two op-amps as voltage followers,  one of them does not load the input signal, the other one does-  see the figure below.

The signal at inaP3_3 (port P3[3] ) is fine, no problem.  But at inbP0_2 (port P0[2]) ,  the AC component is removed and I only have the DC portion of Vin  (1kHz,  0.5Vpp with 0.3V DC offset).  At lower frequencies I start to see more AC component.  As if there's a cap on the input.  

I'm using the CY8Ckit-059, so I checked the schematic and did not see anything connected to this pin. 

Can anyone suggest how this could be happening?  

opamploading.png

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EvPa_264126
Level 7
Level 7
500 replies posted 250 replies posted 100 likes received

It seems it was already:

If you have CY8CKIT-059 and you have not deleted C12 (P0.2) then this is the problem.

look here:       https://community.cypress.com/thread/12559

You will have to either delete or use another contact.

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