Spirox Corporation

Chun Wei Lin

Ching Hsiang Yang

A built-in self-test apparatus for a digital-to-analog converter uses a differentiation unit for differentiating a digital-to-analog (DA) signal to obtain the differences between pulses of the analog signal. Next, the analog signal is converted into a digital signal in the light of a threshold voltage by a Schmitt trigger unit. Then, the duty cycles of the digital signal are calculated by a duty cycle retriever, and transmitted into a signature analyzer to calculate the differential non-linearity for error analysis. For processing a high-speed DA signal, the circuit disposed before the differentiation unit may use a test pattern unit, a sample-and-hold circuit and a logic circuit to lower the speed of the DA signal.

Built-in self-test apparatus and method for digital-to-analog converter

A constant current source with threshold voltage and channel length modulation comprises a set of cascade transistors and a compensation circuit electrically connected to the set of cascade transistors so as to form a feedback circuit, in which the set of cascade transistors including a first MOS transistor and a second MOS transistor, and the compensation circuit comprises a third MOS transistor, a fourth MOS transistor, a sixth MOS transistor and a seventh MOS transistor. The gate terminal of the third MOS transistor is connected to the gate terminal of the second MOS transistor. The fourth MOS transistor is connected to the third MOS transistor in serial, and the gate terminal of the fourth MOS transistor is connected to the gate terminal of the first MOS transistor, and the second terminal of the fourth MOS transistor is connected to a current-supplying circuit. The gate terminals of the sixth and seventh MOS transistors are electrically connected to the current-supplying circuit, and a current is generated by mirroring flows through the third MOS transistor.

Constant current source with threshold voltage and channel length modulation compensation

A built-in-self-test apparatus for an analog-to-digital converter includes a digital-to-analog converter, a low-pass filter, a histogram analyzer and a software engine. The digital-to-analog converter is intended to generate a first signal. The low-pass filter is intended to smoothen the first signal so that an analog-to-digital converter can perform sampling on the smoothened first signal by a second signal, wherein the bit number of the second signal is greater than or equal to that of the first signal, and the frequency of the second signal is a multiple of that of the first signal. The histogram analyzer is electrically connected to the output end of the analog-to-digital converter. The software engine is electrically connected to the output end of the histogram analyzer so as to display the characteristics of the analog-to-digital converter.

Built-in-self-test apparatus and method for analog-to-digital converter

A constant current source with threshold voltage and channel length modulation includes first, second, third, fourth and fifth MOS transistors. Each of the MOS transistors has gate, first and second terminals. The first terminal of the second MOS transistor is coupled to loading impedance, and its second terminal is coupled with the first terminal of the first MOS transistor. The gate terminal and first terminal of the third MOS transistor are together coupled to the gate terminal of the second MOS transistor, and its second terminal is coupled to the first terminal of the fourth MOS transistor. The gate terminal and first terminal of the fourth MOS transistor are coupled to the gate terminal of the first MOS transistor, and its second terminal is coupled to a first reference voltage. The gate terminal and second terminal of the fifth MOS transistor are respectively coupled to a second reference voltage and a third reference voltage, and its first terminal is coupled to the gate terminal and first terminal of the third MOS transistor.

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Changhua, China

Chun Wei Lin