Confusion in PSoC-4 OP Amp datasheet

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Mrinal
Level 4
Level 4
First solution authored 50 replies posted 25 replies posted

Pleasehelp me understand the op-amp datasheet of psoc-4

   

The datasheet of PSoC-4 Op-Amp reads:

   

[1] I_OUT_HI = 10mA (minimum)

   

max and typ are not specified. What is the meaning of minimum 10mA?

   

[2] V_OUT @ I_Load  10mA = 0.5V min and Vdda - 0.5V max

   

What is the meaning of this? The output should not fall below 0.5V?

   

[3] It written.... "Low resistive connections are made from the

   

Opamp to three select pins to provide optimal performance."

   

What's the meaning of this? Does it mean that only three pins of the GPIO can work faithfully with the op-amp? Which three pins?

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Bob_Marlowe
Level 10
Level 10
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[1] The opamp can sink or source 10mA (guaranteed) but it can be more.

   

[2] When sinking 10mA the output voltage offset is 0.5V, when sourcing 10mA the output voltage offset is -0.5V (output is then Vdda -0.5V

   

[3]Each of the opamp has dedicated pins, they may be used by another component when not used by an opamp. Since there are different sockets for PSoC4 easiest is to build the project that uses opamps and let the fitter choose the pins. In the pin-view the preferred use of a pin is shown.

   

 

   

Bob

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ETRO_SSN583
Level 9
Level 9
250 likes received 100 sign-ins 5 likes given

3) See the dedicated table chart in this ap note -

   

 

   

    

   

         

   

http://www.cypress.com/?rID=93401     AN86439 - PSoC® 4 - Using GPIO Pins

   

 

   

What do you need to drive with the OpAmp, there are ways to increase current ?

   

 

   

Regards, Dana.

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DennisS_46
Employee
Employee
100 sign-ins 50 likes received 50 solutions authored

Bob:

   

Almost right. This is an output swing limit, not an offset.

   

2. When driving high, the opamp will meet spec when sourcing current up to an output voltage of Vdd-0.5V. It may go further at the specified load, but no guarantee. Similarly, when when sinking, the output will drive current down to an output voltage of 0.5V. Again, it may go further at the specified load, but no guarantee.

   

---- Dennis

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Bob_Marlowe
Level 10
Level 10
First like given 50 questions asked 10 questions asked

@Dennis,

   

Yes, output swing limitation. I just had a language limitation. 😉

   

 

   

Bob

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Mrinal
Level 4
Level 4
First solution authored 50 replies posted 25 replies posted

  Thanks everyone for the reply!

   

I need to sense three different voltages in the range of 0V-500V DC. 

   

Since the interface has large value resistor dividers (200kohm/1kohm), I want to use the op-amp as a buffer to the ADC.

   

Also since there are only two op-amps and three input voltages, the op-amps must be multiplexed.

   

Please could you provide a rough estimation of time, as to how long must the op-amps stay in one position to stabilize its output?

   

Thanks

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