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Original question:

TLC7524: Is there a simple way to generate a non symmetric wave pattern

TLC7524: Does my TINA mimic the DAC accurately.

Doug Smyth
Prodigy 220 points
Part Number: TLC7524

I had help from a previous post and I thank you. I tried to make a close match TINA design to the TLC7524. The DB pins are driven manually instead of using 3.3v logic.

My pins of interest are VREF => +5v, VDD => +5v but not shown, OUT1, OUT2, and Rfb.

See picture. My TINA works well where the point at Rfb is negative and it can make the voltage value between R117(R3) and R123(R2) positive or negative.

By measuring resistance between OUT1 and Rfp on an unconnected, I measured 12K ohms. I then made the assumption for the rest of the R values. 

I am having issues with the voltage values on my PCB at VF! and VF2 TLC7524.TSC - TINA.pdfTLC7524cc.TSCas if R14 is very much different. My voltage does not appear to  follow the binary value of the DB pins. Will the drawing model I have  of the resistor ladder give an accurate representation of the DC output of the TLC7524?

  • 0
    TI__Guru 53433 points

    Hi Doug,

    A few things were incorrect on your model.  First - are you still trying to get a -3V to 9V range?

    I have made comments assuming you are.

    1. Last 2R leg (R4 and R5) should total 24kΩ.  I changed R5 to 12kΩ.

    2. R2, R3, and R7 needed to be scaled with the R values if you want to keep the -3V to 9V range.

    The opamp you selected is not rail to rail output, so I could not reach +9V with a +9V supply.  I changed V2 to be +12V.

    TLC7524cc-pf.TSC