I understand that practically any op amp can be used in single-supply mode as long as the application (interface, measurement, etc) does not require dual-supply for specific reasons.

  • Is there a reasons why the MIC920 (being a general purpose op amp) does not list single-supply (i.e. 0-5 V) as an option?

  • Is there a way to determine if it's rail-to-rail?

The planned use would be amplification of mV level positive-only pulse signals by 100-1000 times between 500 Hz - 20 kHz for reading by an MCU.


Look at the Maximum Output Voltage Swing.

With \$\pm\$5V supply voltage, the output range is \$\pm\$3V. So your output will not got to ground in a single supply, but will be stuck at a minimum voltage of at least 2V.
With \$\pm\$9V the datasheet is even more conservative and specifies a headroom of -2.8V.

These values are given for a load resisitance of 2k\$\Omega\$, so if your load will be high impedance, then the minimum output voltage will probably be a bit higher.
But the OpAmp is clearly not designed as a single supply device, as the output is not nearly R2R.

Figure 2-12 shows you the negative output voltage for \$\pm\$9V supply rails vs. output current - and even at 0mA the output will not go below -8V. So even with a really high impedance load your output would not be able to go lower than 1V above ground. enter image description here

  • \$\begingroup\$ Thank you for the explanation. So for example, if I use the conventional 3.3V single-supply from a MCU to supply the MIC920, would I get a 0-3V maximum output swing...basically a rail-to-rail output? \$\endgroup\$
    – TommyS
    May 12 at 6:28
  • 1
    \$\begingroup\$ Sorry, just saw the rest of your comments. I understand. Not a good fit for a rail-to-rail single-supply op amp. \$\endgroup\$
    – TommyS
    May 12 at 6:29

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