Method of testing an analog-to-digital converter
AssigneeU.S. Philips Corporation
InventorsRonald De Vries, Botjo Atzema
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Abstract
Only the value of the least-significant bit, or of some of the less-significant bits is used in order to test an analog-to-digital converter in an integrated circuit. The information concerning the differential and the integral non-linearity can be determined from the values of said less-significant bit. Furthermore, the functionality of the analog-to-digital converter is tested by counting the number of changes of the least-significant bit and by comparing this number with the value formed by the other bits.
Claims27
A method of testing an analog-to-digital converter in an integrated circuit, which method comprises the following steps:
- supplying an input of the analog-to-digital converter with a test signal which varies in time and covers a given voltage range in order to form a series of successive code words, each of which comprises a plurality of bits, on outputs of the analog-to-digital converter,
- excluding at least the most significant bit from the outputs of the analog-to-digital converter to form a set of bits excluding at least the most significant bit,
- determining the number of occurrences of code words having one or more given values in the series by examining the set of bits, and
- characterizing the differential and/or the integral non-linearity of the analog-to-digital converter on the basis of the number of occurrences determined.
An integrated circuit with an analog-to-digital converter which includes an input for receiving a test signal and outputs for supplying a first number of bits which together constitute a code word converted from the test signal, characterized in that a second number of the outputs, said second number being less than said first number, otuput less-significant bits of the code word and are coupled to a respective external pin of the intergrated circuit while excluding the other outputs.
An integrated circuit, including an analog-to-digital converter having an input for receiving a test signal and outputs for supplying a number of bits which together constitute a code word converted from the test signal, the analog-to-digital converter being arranged to take samples of the test signal under the control of a clock signal, characterized in that
- the integrated circuit includes a first counter for counting a number of periods of the clock signal between changes of value of the least-significant bit.
Dependencies are inferred from the claim text.