SBOA594 August   2024 OPA2990

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1 Introduction
  5. 2 Circuit Description
  6. 3 Supporting Multiple Output Ranges
  7. 4 Resistor Sizing, M2 Selection, and Other Design Considerations
  8. 5 Mode and Range Control
  9. 6 Supply Level for Current Output
  10. 7 Supply Levels for Voltage Output
  11. 8 Protection Features
  12. 9 Measurement Results
  13. 10Power Consumption
  14. 11Error Monte-Carlo Analysis
  15. 12Rise and Fall Times
  16. 13Building Multi-Channel Output
  17. 14Summary
  18. 15References

9 Measurement Results

A prototype is built for the proposed circuit and several measurements were conducted to test the performance, the following sections show those results in detail.

Conditions: ±12V supply rails, 1kΩ Load, output is averaged over 8k samples. Table 9-1 shows the measured output, supply currents in mA, and rms noise in uV, as well as corresponding effective resolution in bits. For this test, both inputs and Vref=2.5V are generated by a low noise source.

Table 9-1 Bipolar ±10V Voltage mode
vin Vout I(vcc) I(vss) rms noise Resolution
0 -10.09124 0.232 -10.592 0.345 17.1
0.625 -5.03302 0.233 -5.418 0.366 17.1
1.25 13.63853m 0.274 0.297 0.365 17.1
1.875 5.06036 5.373 0.238 0.369 17.0
2.5 10.10703 10.533 0.24 0.374 17.0

Conditions: ±12V supply rails, 1kΩ Load, output is averaged over 8k samples. Table 9-2 shows the measured output, supply currents in mA, and rms noise in uV, as well as corresponding effective resolution in bits.

Table 9-2 Unipolar 0-5V Voltage Mode
vin vout I(vcc) rms noise Resolution
0 -0.739mV 0.221 0.109 17.5
0.625 2.51609 2.791 0.112 17.4
1.25 5.04145 5.369 0.14 17.1

Conditions: +24V supply, 1kΩ Load, output is averaged over 8k samples. Table 9-3 shows the measured output, supply currents in mA, and rms noise in nA, as well as corresponding effective resolution in bits.

Table 9-3 0-20mA Current Mode
vin iout I(vcc) rms noise Resolution
0 1.37077u 0.253 207 18.9
1.25 10.08287 11.73 283 18.4
2.5 20.16957 22.919 279 18.4

If the 4-20mA mode is enabled, Table 9-4 shows the case of zero input

Table 9-4 4-20mA Current Mode
vin iout I(vcc) rms noise Resolution
0 4.07328 5 276.8 18.5