Abstract: A signal output circuit includes a slope control circuit, a capacitor, a noise detector circuit and a fail-safe circuit. The slope control circuit charges and discharges the capacitor, the first terminal of which is connected to an output terminal, according to the control signal level, and drives transistors using the voltage of the second terminal of the capacitor, thereby controlling the slope of the output single. The noise detector circuit detects noise superimposed on the output terminal. When noise is detected, the fail-safe circuit performs a forced drive operation on the transistor to output the output signal at a level corresponding to the level of the control signal is output, regardless of the transistor being driven by the slope control circuit.

Abstract: A signal output circuit includes a slope control circuit, a capacitor, a noise detector circuit and a fail-safe circuit. The slope control circuit charges and discharges the capacitor, the first terminal of which is connected to an output terminal, according to the control signal level, and drives transistors using the voltage of the second terminal of the capacitor, thereby controlling the slope of the output single. The noise detector circuit detects noise superimposed on the output terminal. When noise is detected, the fail-safe circuit performs a forced drive operation on the transistor to output the output signal at a level corresponding to the level of the control signal is output, regardless of the transistor being driven by the slope control circuit.

Abstract: Operation noise and charge error of a charge pump circuit are reduced, thereby the jitter characteristics and the spectrum characteristics of a PLL circuit are improved, and further a time period elapsed until the PLL circuit is locked is shortened. The charge pump circuit 36 receives a control signal depending on an output of a phase comparison circuit 34 from a control circuit 35, and comprises a first P-channel MOS transistor P1, a second P-channel MOS transistor P2 and a third P-channel MOS transistor P3, and a first N-channel MOS transistor N1, a second N-channel MOS transistor N2 and a third N-channel MOS transistor N3, and a first current source 61, a second current source 62, a third current source 63 and a fourth current source 64.

Abstract: Operation noise and charge error of a charge pump circuit are reduced, thereby the jitter characteristics and the spectrum characteristics of a PLL circuit are improved, and further a time period elapsed until the PLL circuit is locked is shortened. The charge pump circuit 36 receives a control signal depending on an output of a phase comparison circuit 34 from a control circuit 35, and comprises a first P-channel MOS transistor P1, a second P-channel MOS transistor P2 and a third P-channel MOS transistor P3, and a first N-channel MOS transistor N1, a second N-channel MOS transistor N2 and a third N-channel MOS transistor N3, and a first current source 61, a second current source 62, a third current source 63 and a fourth current source 64.