ADC passive level shift
ADC passive level shift with explicit circuit assumptions and worked equations.
Development preview. Check the assumptions below before relying on a result. Calculations run in your browser.
How it calculates
Conductance weights: Vout = α Vin + β Vref; α = Rth/Rin, β = Rth/Rref
Mapping: α = (Vout,H − Vout,L)/(Vin,H − Vin,L)
Offset: β = (Vout,L − α Vin,L)/Vref
Assumptions
- The reference is a stiff voltage source. Three branches join at the ADC node: input, reference and ground. Source resistance is included in the input branch. This passive circuit only supports positive slopes and nonnegative conductance weights.
Worked example
These are the calculator's default inputs. Change any input above to recalculate.
Inputs
- Input low
- -10 V
- Input high
- 10 V
- Output low
- 0 V
- Output high
- 3.3 V
- Reference rail
- 3.3 V
- Desired Thevenin resistance
- 1000 Ω
- Input source resistance
- 1 Ω
- ADC leakage into node
- 0 A
Results
- Input resistor excluding source
- 6059.61 Ω
- Reference resistor
- 2000 Ω
- Ground resistor
- 2985.07 Ω
- Total input branch resistance
- 6060.61 Ω
- Gain
- 0.165
- Offset
- 1.65 V
- Leakage error
- 0 V