The TLC8044 is a 12-bit analog-to-digital interface subsystem for charge-coupled device (CCD) image sensors and scanners. An input multiplexer allows color operation with a single on-chip 12-bit ADC. The TLC8044 uses DSP circuits to correct for nonideal CCD image sensor and scanning system characteristics. Cost effective gray scale operation is obtained using a single multiplexer input. The TLC8044 three-channel input multiplexer and sampling function has two basic modes of operation: normal sampling and correlated double sampling. The internal sample and hold allows all three channels to be sampled simultaneously in color operation. Three DACs (8 bits + sign) are provided to allow bipolar adjustment of the dc level of the signal at the ADC input. Digital dc restoration is provided following the ADC. Variations in offset and luminance across a scan are dynamically corrected on a pixel-by-pixel basis, using calibration data provided by an external data store. Provisions are made for global adjustments of gain, contrast and color balance, and offset for brightness. The output word length can be programmed to 8, 10, 12, or 16 bits, and a programmable threshold detector is provided for use during calibration and OCR applications. The TLC8044 is characterized for operation from 0C to 70C.