DAC8564: Suit amp with DAC8564 For 4-20mA

Chen Alex1

Expert 2405 points

Part Number: DAC8564
Other Parts Discussed in Thread: OPA333, OPA317, OPA391, OPA191, XTR111, XTR300

HI SIR

I want to design a 4-20mA Function which use the DAC8564,

Did you have suggestion AMP for this?

thanks

6 months ago

0 Katlynne Jones 6 months ago

TI__Mastermind 28488 points

Hi Alex,

Joseph will provide you a suggestion next week after the holidays.

Best,

Katlynne Jones

0 Chen Alex1 6 months ago in reply to Katlynne Jones

Expert 2405 points

ok wait your reply

thanks

0 Joseph Wu 6 months ago in reply to Chen Alex1

TI__Guru* 93085 points

Alex,

I'm at work for today, but I'm back out tomorrow. I'll be back again next week.

The op-amp you need depends on what sort of 4-20mA application you need.

If you need the op-amp for a transmitter circuit, then the op-amp only needs to drive the base of a BJT transistor to control the current of the loop. This is demonstrated in the following analog engineer's circuit:

https://www.ti.com/lit/an/slaa866/slaa866.pdf

In the circuit, you would need something with the desired bandwidth and low offset. The circuit uses the OPA317, but I've seen the OPA333 and OPA391 used as well.

If you need the op-amp for an analog output then you would use DAC as part of a voltage-to-current conversion circuit. Again, I think you would want to target the desired bandwidth and have a good offset.

https://www.ti.com/lit/ug/slau502/slau502.pdf

If you need something with high voltage and a low offset, I think the OPA191 might be a good choice.

If you need both the 4-20mA output and a voltage output, you could use an voltage-to-current IC like the XTR111. If you need the voltage-to-current conversion and want to translate the output voltage to a higher range, you could use the XTR300.

https://www.ti.com/product/XTR111

https://www.ti.com/product/XTR300

Joseph Wu

Data converters

Data converters forum

DAC8564: Suit amp with DAC8564 For 4-20mA