3.3V to +/-12V conversion

Rick Adolf

Other Parts Discussed in Thread: DAC60096, DAC81408, DAC81416, TLV61048

I need to produce a 0 to +/-11V or 0 to +/-3V 150Hz square wave (minimal current (<20mA) for a large FAANG company. Thinking about using a uC with a DAC (0-3.3V) output and converting it to bipolar. What pieces might TI have (+/-12V tracking supply, op-amp, reference voltage, etc.)?

Thanks!

over 2 years ago

0 Paul_Frost over 2 years ago

TI__Guru 52663 points

Hi Rick,

Take a look at the DAC81408, DAC81416 family. Depending on how many channels you need and the resolution, you can look at the 12- and 14-bit versions. We also have a 96-channel DAC, DAC60096. These devices have some TOGGLE input pins that make it very easy to create square waves. You set the high code and low code, and the DAC will switch between the two based on the TOGGLE pin.

Thanks,

Paul

0 Rick Adolf over 2 years ago in reply to Paul_Frost

Intellectual 310 points

I only need one channel and already have a micro (with a 10-bit DAC), so the DAC is taken care of. What I need help with is the follow on and support circuits (op-amp with 2 different gains (analog switch to adjust the feedback ratio, maybe?) and the +/-12V low current supply

0 Paul_Frost over 2 years ago in reply to Rick Adolf

TI__Guru 52663 points

Hi Rick,

You could do that a few different ways. If you use a higher resolution DAC you could omit the analog switch and just set the DAC to have a fullscale range of ~±11.5V, then you can just select codes to create your square wave peak values. Creating a bipolar range from a unipolar input is pretty straight-forward. Take a look a this reference design:

https://www.ti.com/lit/pdf/SLAA869

Thanks,

Paul