An unusual way to generate a sawtooth signal.
1) The counter ramps up from 0000 to 1111 providing 16 digital levels.
2) The operational Amplifier is driven by a R-2R ladder thus, the inverting input varies from a minimum voltage to the maximum generated by the ladder.
3) The OPAMP gain is set by Rf/Ri.
4) At the output, the filter composed by the 3.3 Kohm resistor and 1 uF capacitor smooths the opamp Vout and the diode suddenly discharge the capacitor when the digital code is "0000".
Note: Rf is the reaction resistor (50K) and Ri is the one connected to invering pin.<br>
