Switching circuits AD5451

I'm moving this to the Precision DACs forum where someone can help you.

Hi Vladimir,

My understanding to your question is why does the DAC use current or voltages as outputs. The AD5451 is an IOUT DAC that uses an amplifier at the back-end to convert the current to voltage. Current is used because the part is designed to perform on multiple modes of operations (unipolar, bipolar, etc) and to have a very flexible input reference pin (+/- 10V). This way, the user can use the part to an even wider range of applications.

Regards,

Mark

Hi,

From a quick glance on your schematic, why is your IOUT connected to the non-inverting input of the amplifier?

Regards,

Mark

Thank you for the wrong address.

     Hi, msamera. You heard me right. I will write more fully with what I ran.

     By default, when the circuit voltage of the DAC output is 5 volts (equal to the supply voltage), the reference voltage can vary in the range of 2.5 to 5 volts. Why output voltage equal to the reference in the regulation trimmer? I need to make so that when the power to the unit at the DAC output voltage was low, I need to make so that when the power to the unit at the DAC output voltage was low, like in AD7399 (voltage outputs).

That's part of my circuit for clarity.

Operational amplifier I need to increase the output current DAC (load capacity). When connecting external circuits.

Used to exclude signal of negative polarity, which is unacceptable for the load. Then I realized that in a unipolar supply voltage operational amplifier does not matter at which input to signal.

And it is necessary for fine adjustment of the output voltage in the range of 0.01 - 5V.

Hi Vladimir,

Let me see if I got your message clearly. You want the following:

• Output voltage range from 0.01V to 5V
• Reference voltage that can vary from 2.5V to 5V
• Operational amplifiers to increase loading capability of the DAC output

If these are correct, you may use the unipolar mode operation of the DAC to get an output range of 0 to -Vref. Connect this output to an inverting operational amplifier circuit with a gain of -1 to get your desired positive output range.

Regards,

Mark

Hi msamera, If properly understood, I connected <IOUT1> DAC output to the inverting input of the amplifier and its output is connected with a direct entrance to gain 1. Here is the modified circuit.