Abstract: A circuit system is provided capable of improving the throughput thereof by eliminating the operational constraint that if the operating frequency of a content addressable memory is lower than the operating frequency of a system LSI, two system clocks should be provided, or the higher frequency should be synchronized with the slower system clock. A clock control circuit (103) for down-converting an internal clock (?1) of a LSI (101) is provided, and a control signal whose frequency is made lower is used to operate a content addressable memory circuit (102).

Abstract: A semiconductor device of the present invention has a memory cell array having plural CMOS static memory cells provided at intersecting portions of plural word lines and plural complementary bit lines. In the memory cell array, a switch MOSFET which is in an OFF state in a first operation mode and in an ON state in a second operation mode different from the first operation mode and first-conductivity-type and second-conductivity-type MOSFETs having a diode configuration are provided in parallel between a first source line to which sources of first-conductivity-type MOSFETs constituting first and second CMOS inverter circuits constituting the plural static memory cells are connected and a first power supply line corresponding to the first source line. A second source line to which sources of the second conductivity-type MOSFETs constituting the first and second CMOS inverter circuits are connected is connected to the second power supply line corresponding thereto.

Abstract: A semiconductor device of the present invention has a memory cell array having plural CMOS static memory cells provided at intersecting portions of plural word lines and plural complementary bit lines. In the memory cell array, a switch MOSFET which is in an OFF state in a first operation mode and in an ON state in a second operation mode different from the first operation mode and first-conductivity-type and second-conductivity-type MOSFETs having a diode configuration are provided in parallel between a first source line to which sources of first-conductivity-type MOSFETs constituting first and second CMOS inverter circuits constituting the plural static memory cells are connected and a first power supply line corresponding to the first source line. A second source line to which sources of the second conductivity-type MOSFETs constituting the first and second CMOS inverter circuits are connected is connected to the second power supply line corresponding thereto.

Abstract: A circuit system is provided capable of improving the throughput thereof by eliminating the operational constraint that if the operating frequency of a content addressable memory is lower than the operating frequency of a system LSI, two system clocks should be provided, or the higher frequency should be synchronized with the slower system clock. A clock control circuit (103) for down-converting an internal clock (?1) of a LSI (101) is provided, and a control signal whose frequency is made lower is used to operate a content addressable memory circuit (102).