OPA827: OPA 827

Hi Timothy,

For higher voltage op amp applications using supplies such as +/-6 V to +/-18 V, JFET input op amps can offer better parametric performances compared to their bipolar, and CMOS counterparts. It just depends on the particular ones of interest. One characteristic of JFET circuits is they tend to require higher internal operating voltages than their bipolar and CMOS counterparts. For that reason the availability of low-voltage, high-performance JFET input op amps is somewhat limited. That might be a drawback in some cases.

We have an op amp technology session that we present during some TI Tech Days. There are some tables in the session materials where general comparisons of op amp parameters are made for CMOS, bipolar,and JFET op amps.  I've copied the tables below and hopefully they provide the information you need. Note the green check and red "x" boxes.

If you have specific parameter questions let us know.

Regards, Thomas

Precision Amplifiers Applications Engineering

Thomas thank you. Thats what I was thinking. A new question came up.
Knowledge of low noise and precision electronics techniques, including signal guarding, and compensation of thermal effects.

Do you have any topics on signal guarding and compensation of thermal effects?
Regards
Timothy

Hi Timothy,

We have general information about input guarding in the datasheets for ultra-low input current op amps. See section 10 in the LMC6001 datasheet as an example.

http://www.ti.com/lit/ds/symlink/lmc6001.pdf6001

We have some information about thermal effects due to thermocouple formation on PC boards. I will need to locate that information.

Regards, Thomas

Precision Amplifiers Applications Engineering

Hi Timothy,

Please see the attached PowerPoint file regarding PC board thermocouple formation.

Regards, Thomas

Precision Amplifiers Applications Engineering

PCB_Thermocouples.pptx