This calculator has two parts: an annotated schematic at top and a table of contributing error sources at bottom. Op Amp parametric data is automatically entered in the appropriate fields of the bottom table, and default values for the application parameters have been assigned to the application-specific fields at top. All input data can be manually overridden, however output fields (surrounded by light gray) cannot be changed.
After entering data in a field, hit tab or click "Update" to compute derived values and see node voltages updated on the schematic. If the inputs are out of range an alert will appear. If the combination of inputs causes internal or external output limits to be exceeded, the problem node value will be highlighted in red and an "Out of Range!" message will appear. When this message is present, all node values should be considered invalid. Do not leave fields blank: if you see NaN (Not a Number), this means that insufficient data was entered to compute a value.
"Gain" and "RF" are computed automatically from one another, based on the value of "RG". The calculation is ideal and doesn't reflect RS, RX and RL, for example.
Equations listed in the "Calculation" column are approximate and reflect the worst case between the three buffer choices. Modifications to the equation for particular buffer types are indicated in (). For example (1/2 : noninv) means an additional factor of 1/2 should be used to compute this quantity for noninverting buffers.
Specs shown are worst-case for the selected part, if available, otherwise typical values are used. If no spec is available, "N/S" will appear in that field and an ideal spec (usually zero) will be used for the calculation. Please note that it is highly unlikely that all worst-case specs would ever be present at the same time in the same part. The designer should always refer to the appropriate datasheet and substitute numbers most appropriate to his/her application. All calculations are approximations with errors displayed and summed in absolute PPM, even though in some scenarios the actual values would be negative.