| 摘要 |
PURPOSE:To reduce the mixture of a noise into an analog circuit by using an IIL logic element for the logic control part of an A/D converter. CONSTITUTION:The driving part for electric-current switching transistors 204 and 205 for changing over reference electric-current sources provided at the input side of the comparator of an A/D converter is composed of flip-flop 201 of IIL. Through the operations of clamping circuits 213 and 214 provided to the IIL output part, a differential input to transistors 204 and 205 is held at about 0.7V. Therefore, an about 0.1V threshold voltage for driving transistors 204 and 205 is sufficient. Consequently, the generation of spike pulses can be reduced because of small logic amplitude, so that the leakage of noises to the analog part can be reduced. |
