DAC8574: Output Current

Part Number:DAC8574

Hello

We use DAC8574 to output 0~5V to control the air valve.  VrefH=5V, VrefL=GND.

Does the current of Vout A~D all from VrefH?

If each Vout current =20mA, do we need VrefH input current=80mA?

Or we need add amplifier after Vout？

Thanks!

BR

Jasmine