Overview

The MN86157 contains a 7-bit A/D converter for use in correcting, at the bit level, shading distortion for signals from image sensors, optics, and similar sources. It uses external RAM to support adaptive correction that responds to changes in distortion patterns. It also uses ROM to provide fixed correction when a white reference plane signal is not available.

The chip is also usable as a stand-alone A/D converter.

Features

• Choice of correction range (50 or 75) depending on extent of shading distortion

• Parallel A/D converter functions

Resolution: 7 bits

Non-linearity: ±1/2 LSB

Conversion speed: max. 5 MHz

Note: This is the guaranteed design value for the

chip used as a stand-alone A/D converter. The

guaranteed value at shipment is ±3 LSB

• Ability to start and stop clock in the middle of a line to support CdS contacting image sensors and other devices with variable scanning rates

• Overflow pin that simplifies task of adding auto background control (ABC) circuit

• Single 5 volt power supply

• Guaranteed TTL levels for input

Applications

• Facsimile equipment