Part Number: DAC80508
Tool/software:
I have a question about this reference circuit (Page 37, Section 9.1.2, DACx0508 Octal, 16-, 14-, 12-Bit, SPI, Voltage Output DAC with Internal Reference datasheet (Rev. D)). If I am using the 2.5V internal reference, and my goal is to pump a certain current through the load into ground, the stated formula for I_L would suggest that I am able to simply setup this circuit and use the DAC to configure a current amount. However, as this is said to be a bidirectional current source, it is unclear which direction the current would go. Furthermore, from referencing TI's Howland current pump circuit documents (https://www.ti.com/lit/an/sboa436/sboa436.pdf and https://www.ti.com/lit/an/snoa474a/snoa474a.pdf), it seems that if I wanted to pump current through the source into ground, I would need to ground the inverting input, and set the voltage of the noninverting input, which is the opposite of what is shown in this datasheet design reference. Am I missing something? Also, if I were to want to source current bidirectionally, would I not need the DAC to output a negative voltage to reverse the direction of the current across the load, as the other op-amp input is grounded? If so, this seems to not agree with the electrical specifications for Vrefin (1.25V to 5.5V) listed in the datasheet for the DAC. Some clarification would be greatly appreciated!
