HIGH_SPEED_12_BIT_A_D_CONVERTER

Published:2009/7/2 4:00:00 Author:May | From:SeekIC

This system completes a full 12-bit conversion in 10 μs unipolar or bipolar. This converter will 6e accurate to ±1/2 LSB of 12 bits and have a typical gain TC of 10 ppm/℃. In the unipolar mode, the system range is 0 V to 9.9976 V, with each bit having a value of 2.44 mV. For the true conversion accuracy, an A/D converter should be trimmed so that given bit code output results from input levels from 1/2 LSB below to 1/2 LSB above the exact voltage which that code represents. Therefore, the converter zero point should be trimmed with an input voltage of 1.22 mV; trim R1 until the LSB just begins to appear in the output code (all other bits 0 ). For full-scale, use an input voltage of 9.9963 V (10 V-1 LSB-1/2 LSB); then trim R2 until the LSB just begins to appear (all other bits 1 ). The bipolar signal range is -5.0 V to 4.9976 V. Bipolar offset trimming is done by applying a -4.9988 V input signal and trimming R3 for the LSB transition (all other bits 0 ). Full-scale is set by applying 4.9963 V and trimming R2 for the LSB transition (all other bits 1 ).



Reprinted Url Of This Article:
http://www.seekic.com/circuit_diagram/A-D_D-A_Converter_Circuit/A-D_converter/HIGH_SPEED_12_BIT_A_D_CONVERTER.html

Print this Page | Comments | Reading(3)