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Part Number: ISO7741
Hi, I'm using TI's DAC60504 to create a bipolar signal (ref. slaa869) and a Howland current pump.
This bipolar signal is fed to the Op Amp's input
Currently, both the OPA551 Op Amp (+30V, -30V supplied) and the DAC DAC60504 is tied to the same GND;
GND - The load resistor connected to the Op Amp - DAC GND
However, I need to use separate the GND and I noticed the Isolation solutions.
Since this current pump drives +30, -30V with 60mA max, can I use the Isolation solutions to use separate GNDs?
First, I thought to add a unity gain buffered GND to the load, but I thought the Isolation solution could be better.
-Best Regards, David
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In reply to Koteshwar Rao:
Koteshwar RaoISO7741 can be used to isolate the SPI interface between MCU and DAC.
I think you are mentioning this figure, right?
However, that is not what I want to do. ISO7741 has two GNDs; GND1 and GND2.
For my microcontroller's GND and DAC's GND, I want that to be connected on GND1.
Whereas, if you take a look at my Howland Current Pump circuit,
there is a GND symbol which is connected to the load. I want that to be connected as GND2.
This is how I want to separate the GNDs. Is this applicable? Or do you suggest other methods?
In reply to David__:
Koteshwar Raocould you please let me know if there is any particular reason for not isolating between MCU & DAC instead of DAC & Op-Amp? It is a common practice to isolate between MCU and data converters when isolation is a requirement but do note that there are applications where isolating an analog signal is necessary.
Well, I don't have a specific reason for not isolating the DAC and the MCU. I tested the TI's DAC with multiple launchpads like the MSP430, MSP432 launchpad.
When the DAC and the launchpad used the same GND, it worked nicely for me. So I didn't really felt the necessity.
Since you mentioned this is a common practice to isolate the GND between the MCU and the DAC, may I ask the reason why for doing that?
After your reply, I'll close this thread. Thanks for suggesting an alternative, too.
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