Texas Instruments Corporation

David Walker Guidry

Dale A Heaton

Sasikumar P Cherubal

The invention relates to systems and methods for high-sensitivity detection of input bias current. The invention more particularly relates to platforms and techniques for the calibration and measurement of input bias current in op amps or other devices. In embodiments, the platform can incorporate a servo loop connected to a high-sensitivity test amplifier, such as an instrumentation amplifier. The test amplifier can complete a switchable circuit with the servo loop and detect a calibration input bias current for the test platform, without a production device in place. The device under test can be switched into the servo loop, and the total bias current measured with both the device under test and test amplifier in-circuit. The difference between the measured current with the device inserted and the previously measured calibration current represents the bias current for the subject device, without attaching external meters or requiring reference parts of the production type.

Systems and methods for high-sensitivity detection of input bias current

System and method for testing differential signal crossover in high-speed electronic equipment. A preferred embodiment comprises a test circuit coupled to a device under test (DUT) and an automatic test equipment (ATE). The test circuit comprises a pair of window comparators coupled to a differential mode signal from the DUT, each window comparator configured to compare one of two signals making up the differential mode signal with a voltage boundary when enabled by an enable signal. The ATE is configured to provide clock signals to the test circuit and the DUT and to process data produced by the test circuit to determine if the differential signal crossover meets timing constraints. The test circuit uses undersampling to enable testing of high frequency signals without requiring an extremely high sampling rate.

System and method for testing differential signal crossover using undersampling

A system and method for providing successive approximation, such as can be used by a successive approximation converter or by a coherent undersampling digitizer. The system comprising a memory having a successive approximation value and a comparison system configured to receive and amplify the difference between a test signal and the successive approximation value and to convert the amplified signal to a digital signal. A multi-bit analog to digital convert can be used to convert the amplified signal to a digital signal.

System and method for successive approximation

According to one embodiment of the invention, a method of sampling a signal is provided. The method includes receiving over a signal path an analog signal generated using a first clock signal by a first device. The method also includes sampling the analog signal using a second clock signal to generate a numeric representation of at least a portion of the analog signal. The frequencies of the first and the second clock signals differ from one another by a known amount. The method also includes communicating over the signal path the numeric representation for receipt by a second device. The signal path experiences loading and at least a majority of the loading of the signal path occurs between the sampler and the second device.

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Rowlett, TX, United States of America

David Walker Guidry