R2R digital to analog converter.avi
4,892 views · Published 25 July 2017 · 3:59 · Indexed 8 October 2026
Channel: All About RC · 2017 · Education
A basic R–2R resistor ladder network is shown in the video. Input bits are driven from digital logic gates. Ideally, the bit inputs are switched between V = 0 (logic 0) and V = Vref (logic 1). The R–2R network causes these digital bits to be weighted in their contribution to the output voltage Vout. Depending on which bits are set to 1 and which to 0, the output voltage (Vout) will have a corresponding stepped value between 0 and Vref minus the value of the minimal step, corresponding to bit 0. The actual value of Vref (and the voltage of logic 0) will depend on the type of technology used to generate the digital signals. For a digital value VAL, of a R–2R DAC with n bits and 0 V/Vref logic levels, the output voltage Vout is: Vout = Vref × VAL / 2^n. For example, in our video, n=3. So 2^3=8 and Vref=10 Vout = 10*0/8 = 0.00 (for 000) Vout = 10*1/8 = 1.25 (for 001) Vout = 10*2/8 = 2.50 (for 010) Vout = 10*3/8 = 3.75 (for 011) Vout = 10*4/8 = 5.00 (for 100) Vout = 10*5/8 = 6.25 (for 101) Vout = 10*6/8 = 7.50 (for 110) Vout = 10*7/8 = 8.75 (for 111)
