| 摘要 |
PROBLEM TO BE SOLVED: To provide a successive approximation A/D converter that implements a low power consumption and a high speed operation on low voltage and suppresses an increase in area.SOLUTION: A sampling circuit samples an analog signal VAIN and generates a comparison signal depending on the sample value and a successive approximation control signal, and generates a reference signal. Capacitors 308-311 are connected to a node 336 and a capacitor 312 is connected to a node 337. In a sampling mode, an analog switch 328 is turned on to connect the node 336 to GND and an analog switch 329 is turned on to connect the node 337 to VDD. An analog switch 332 is turned off in the sampling mode. At the end of the sampling mode, all the switches are turned off before the analog switch 332 is turned on to generate the comparison signal. |
