OPAMP single supply behavior
Introduction
Most OPAMPs work best when powered with a symmetrical power supply having an equal positive and a negative voltage. Depending on the type of OPAMP, the output is either able to reach all the way the negative or positive supply rail or not. When the output is not able to reach the power supply rails, it will usually clip somewhere between 0.7V and 2 volts below the supply rail.
When deciding to power an OPAMP with a single supply (a positive voltage and reference ground), care must be taken to make sure that the OPAMP will work properly, especially when the OPAMP is not a rail to rail input/output (RRIO) type.
The inputs/output of CMOS OPAMPs (f.e. MCP6022) can swing all the way to the positive supply rail and also to ground. Often these CMOS OPAMPs have a limited power supply voltage (like max 5V or 5.5V).
Some OPAMPs are optimized to operate from a single power supply (f.e. LM324, LM358), but that does not mean that the output of the OPAMP will follow the input all the way from ground to the positive supply rail. Often the output does not come closer than 0.7V to 2V from ground or the positive supply rail when the input is either 0V or the positive supply rail, except for rail to rail input/output OPAMPs.
It is crucial to first check the datasheet to find out if the OPAMP can operate from a single supply. Then check the input common mode range to see if the input can go all the way down to ground and/or to the power supply rail. Then check if the output can swing all the way down to ground and/or the power supply rail. This information will tell you how the OPAMP will behave when powered with a single supply voltage, so you have an idea what to expect when you design an OPAMP circuit.
Test setup
The OPAMPs were configured as a voltage follower powered by a single supply of +10V DC and with a 1kHz sine wave at the input having an AC amplitude of 10Vpp and a DC offset of +5V (so the sine was alternating between 0 and +10V).
This way we can see how the OPAMP performs with an input signal that covers the whole power supply range.
None of the OPAMP are rail to rail output/input types. Some of the tested OPAMPs had no internal compensation but external compensation inputs. For these OPAMPs a 47pF capacitor was connected to the compensation inputs.
In the figure below, the test setup for the OPAMPs is shown:
Test results
Here follows the list of tested OPAMP and the test results:
Single OPAMPs
Output range
Max Min Distortion type Suitable for single supply
---- ---- ---------------- --------------------------
AD811AN 9.0V 0.80V Clipped bottom + top Yes
CA3130EZ 8.3V -80mV Clipped top, output reaches ground Yes, input/output can reach ground
CA3140E 7.92V -80mV Clipped top, output reaches ground Yes, input/output can reach ground
LF356N 8.48V 0.88V 0V input gives max output No
LF357N 8.64V 0.72V 0V input gives max output + oscill. No
LM301AN 9.44V 2.00V Clipped bottom + top Yes, output gets at ca. 0.6V from supply rail
LM308AN 9.12V 0.48V Clipped bottom + top Yes
MC33171P 9.12V 0.00V Clipped top, output reaches ground Yes, input/output can reach ground(slight distortion)
NE538N 9.52V 0.72V Clipped bottom + top + oscillations Yes, output gets at ca. 0.6V from supply rail
NE5534D 9.44V 1.12V Clipped bottom + top Yes, output gets at ca. 0.6V from supply rail
OP77 9.44V 0.64V Clipped bottom + top Yes, output gets at ca. 0.6V from supply rail
UA741CP 9.44V 1.84V Clipped bottom + bulged top Yes
Dual OPAMPs
Output range
Max Min Distortion type
---- ---- ----------------
CA3240 7.92V -80mV Clipped top, output reaches ground Yes, input/output can reach ground
LF353N 9.44V 1.44V 0V input gives max output No
LF442CN 8.96V 1.84V 0V input gives max output No
LM358N 8.64V -80mV Clipped top, output reaches ground Yes, input/output can reach ground
LM833N 9.60V 0.80V 0V input gives max output No
MC1458 9.44V 2.08V Clipped bottom + bulged top Yes, output gets at ca. 0.6V from supply rail
MC33078P 9.60V 0.72V 0V input gives max output No
NE532N 8.56V -80mV Clipped top, output reaches ground Yes, input/output can reach ground
NE5512N 8.96V 0.72V Clipped bottom + top Yes
NE5532D 9.44V 1.12V Clipped bottom + top Yes, output gets at ca. 0.6V from supply rail
NE5535N 9.52V 2.00V Clipped bottom + top Yes, output gets at ca. 0.6V from supply rail
NE5538N 9.44V 0.88V Clipped bottom + top + oscillations Yes, output gets at ca. 0.6V from supply rail
OPA249FZ 10.0V 1.76V 0V input gives max output No
RC4558D 9.44V 1.28V 0V input gives max output No
RC4560D 9.44V 1.28V 0V input gives max output No
TL072CP 9.44V 1.28V 0V input gives max output No
TL082ACP 9.44V 0.80V 0V input gives max output No
Quad OPAMPs
Output range
Max Min Distortion type
---- ---- ----------------
LF444CN 8.88V 2,24V 0V input gives max output No
LM324N 8.88V -80mV Clipped top, output reaches ground Yes, input/output can reach ground
MC33284P 9.36V 0.72V 0V input gives max output No
TL034CN 9.36V 0.64V 0V input gives max output No
TL074N 9.44V 1.28V 0V input gives max output No
Datasheet check
First we need to check the datasheet of the OPAMP to see if it suited for operation from a single supply voltage.
Then we need to check the input common mode range and the output range of the OPAMP to find out if the input common mode range includes ground and/or the power supply voltage and also if the output can swing all the way down to ground and/or the supply voltage.
F.e. the datasheet of the LM324 mentions that the valid common mode range is from device ground to Vcc-1.5V. It also specifies the output voltage swing from rail, i.e. : how close the output can swing to either ground (or negative rail for a symmetrical supply) and the positive supply rail.
F.e. the datasheet of the LM358 mentions that the input common mode range includes ground and that also the output can swing to ground even when operated from only a single power supply. The VOL (V output low) is defined as the swing parameter, which is typically 5mV, so very close to ground.
F.e. the datasheet of the CA3240 mentions that the wide common input voltage range typically goes down to 0.5V below the negative supply rail. So the input can go to -0.5V. The output voltage ranges from 3V for a +5V supply to 0.3V. So the output can swing relatively close to ground.