| 摘要 |
PURPOSE:To eliminate deterioration in the accuracy caused by deterioration in a MOSFET by providing 1st and 2nd switching elements comprising MOSFETs and 1st and 2nd resistors to the D/A converter and selecting a voltage applied to the 2nd resistor based on a digital signal to be converted. CONSTITUTION:A ratio of the ON-resistance N-channel MOSFETs 5o, 51H, 5iL to the ON-resistance of the FET 4i is kept to be 2:1 within a range of a high reference voltage VREFH and a low reference voltage VREFL. When a binary digital input signal inputted from an input terminal group 21 is logical H, the FET 5iH is turned on and the FET 5iL is turned off. Furthermore, when the digital input signal is logical L, the FET 5iH is turned off and the FET 5iH is turned on, As a result, a ratio of the ON-resistance of the FETs 5o, 51H, 5iL to the ON-resistance of the FET 4i is 2:1 within a range of voltages VREFH and VREFL and the effect of the on-resistance of the MOSFET switch onto the accuracy is reduced. |
