I use an AD5420 to produce a precise 0-20mA output current.
Is it preferrable to compensate the offset and gain errors by firmware or there is some internal compensation circuitry in the AD5420 to do this ?
In the AD420 the compensation can be done using two external dedicated pins.
Thanks in advance for any suggestion
For improved offset and gain error specification I'd recommend using an External RSET.
Offset Error is +/-0.1%FSR max, and Gain Error of +/-0.08%FSR max.
There is no specific Offset and Gain registers on the AD5420 or a similar trimmable
offset like the AD420.
The AD5755 offers a programmable Gain / Offset option in the internal calibration settings.
I can't find descriptions of how to program Gain / Offset in the datasheet. Only thing I can find about internal calibration registers in the datasheet is in 'power-on state' section, which does not tell how to program gain / offset.
Could anybody advice me where I can find a documentation in which programming gain/offset is explained in detail?
The AD5755 offsets gain and offset registers on the part. (M + C registers).
These are detailed on page 34 of the AD5755 datasheet.
The AD5420 does not have internal gain/offset registers.
Michael (PDA Applications)
Oops. I'm sorry. I missed "AD5755" part and thanks for the clarification.