Delta-Sigma ADC

Delta-Sigma ADC Applet

Definition:

Equation

Parameters

Diagram

Calculate Properties of a 1-bit ΣΔ ADC: top

Parameter

Value

Units

Note

Inputs:
R1 (feedback resistor) Note: An alternate version includes 2 more resistors to change range

R2 (input resistor)

F_Clk (uC clock frequency)

N (#bits in sample)

V_dd (uC supply)

Outputs:
V_Max(max. input voltage)

V_Min (min. input voltage)

V_Range(|VMax-VMin|) =Vdd*R2/R1

T_S (sample period)

F_S (sample rate)

F_N (sample Nyquist freq.)

Notes: top

This calculator is for the case of a microcontroller (uC) digitizing an analog signal using the 1-bit Sigma-Delta (ΣΔ) approach.
You must keep C1=C2 when uC input threshold is at Vdd/2.
There may be chip-chip variations in input threshold level from an assumed Vdd/2. So it may be wise to pick resistors that allow an input range greater than that required... (For example, with R1=R2=100k a max. input of 3.3 volts is expected with the Propeller uC, however, this may not work and R2=150k is advised).

	Parameter	Value	Units	Note
Inputs:	R1 (feedback resistor)			Note: An alternate version includes 2 more resistors to change range
Inputs:	R2 (input resistor)
	F_Clk (uC clock frequency)
	N (#bits in sample)
	V_dd (uC supply)

Outputs:	V_Max(max. input voltage)
V_Min (min. input voltage)
	V_Range(\|VMax-VMin\|)			=Vdd*R2/R1
	T_S (sample period)
	F_S (sample rate)
	F_N (sample Nyquist freq.)

Definition:

Equation

Parameters

Diagram

Calculate Properties of a 1-bit ΣΔ ADC: top

Parameter

Value

Units

Note

Inputs:

Outputs:

Output Format: top

Notes: top