OPA2990: temp drift

When Vout_A is at some value between 0.12 V and 0.2 V, what are the voltages at pins 3, 2, 5, 6, and 7?

Hello Chen,

The VCM for U30B varies from (12V-0.4V) at 4mA to (12V-2V) at 20mA

Near 12mA, the op amp switches between input transistors. This makes 4 to 10mA not quite match 15 to 20mA 

Does that explain your data?

Chen

The thread name says 'temp drift'. Keep in mind the the base currents lost in the current mirrors vary with transistor beta. Beta varies with temperature. You could change to NMOS and PMOS to eliminate base current. 

hi Sir

Did you mean the output current drift ,due to the Transistor beta?

did you have any suggest TI NMOS or PMOS?

thanks

Chen,

Yes transistor beta

I'm not an expert in this product line, but here is a starting point. You can ask a new question with one of these part numbers, to reach an expert. 

CSD17585F5 NMOS Q8

CSD25501F3  PMOS Q2