Abstract: A generalized method for testing DACs (Digital to Analog Converters) and ADCs (Analog to Digital Converters), such as Sigma Delta (Successive Approximation), Pipeline or Flash ADCs. The DACs and ADCs are tested in pairs using a Digital Tester and on chip test circuitry. The DACs and ADCs may be tested at the highest clock frequency allowed in the specification, shortening test time. The test circuits required for this test scheme comprise cell logic two multiplexer cells and an internal Analog Test Bus. This scheme is extendable to the testing of many DACs and ADCs on the same IC. The number of DACs and ADCs need not be equal. Furthermore, the DACs may have more (or less) bits (addresses) than the ADCs. An ADC may be tested with more than one DAC or vice versa to determine which cell is at fault if a test fails.

Abstract: A generalized method for testing DACs (Digital to Analog Converters) and ADCs (Analog to Digital Converters), such as Sigma Delta (Successive Approximation), Pipeline or Flash ADCs. The DACs and ADCs are tested in pairs using a Digital Tester and on chip test circuitry. The DACs and ADCs may be tested at the highest clock frequency allowed in the specification, shortening test time. The test circuits required for this test scheme comprise cell logic two multiplexer cells and an internal Analog Test Bus. This scheme is extendable to the testing of many DACs and ADCs on the same IC. The number of DACs and ADCs need not be equal. Furthermore, the DACs may have more (or less) bits (addresses) than the ADCs. An ADC may be tested with more than one DAC or vice versa to determine which cell is at fault if a test fails.

Abstract: A content addressable memory system has rows and columns of CAM cells. Each CAM cell has a data memory, and comparison circuitry for comparing the data bit of the memory element with a compare data, and for driving a signal onto a match line when the data bit is not equal to the compare data. The comparison circuitry has a mismatch node with a pre-discharge device, and drives a match line drive device coupled to the match line. The mismatch node also couples to a first comparison device having source an output of the data memory and gate coupled to the compare data, and a second comparison device having source a second output of the data memory and gate coupled to compare data. Disclosed is a ternary implementation of the CAM cell also having a mask bit. Also disclosed is CAM timing such that the CAM cells operate without crowbar current.

Abstract: A content addressable memory system has an array of CAM cells. Each row of the array has a match line coupled to a match line pull device. The match line pull devices of each cell are also coupled to a row return line that may be shared with an adjacent row. Each row return line is coupled through a resistive device to a rail. The CAM cells also have a data memory element and comparison logic for comparing query data against the data memory element and controlling the match line pull devices.

Abstract: A buffer circuit and method provide substantially constant output signal edges to facilitate service as a bus driver with enhanced timing flexibility. The buffer circuit includes a NOR gate and a NAND gate for driving output pulldown and pullup transistors. The initiation of current flows through the NOR and NAND gates is controlled by an environmentally adaptive reference circuit. First and second transistors are provided respectively between the NAND gate and the pullup transistor, and between the NOR gate and the pulldown transistor, to produce enhanced sourcing and sinking currents. The enhanced sinking and sourcing currents are timely terminated by switching of the pulldown and pullup transistors to save energy.