The TC7117A is a 3½ digit CMOS analog-to-digital converter (ADC) containing all the active components necessary to construct a 0.05% resolution measurement system. Seven-segment decoders, polarity and digit drivers, voltage reference, and clock circuit are integrated on-chip. The TC7117A drives common anode light emitting diode (LED) displays directly with an 8mA drive current per segment. These devices incorporate a display hold (HLDR) function. The TC7117A reduces linearity error to less than 1 count. Roll-over error (the difference in readings for equal magnitude but opposite polarity input signals) is below ±1 count. High-impedance differential inputs offer 1 pA leakage current and a 1012 Ohm input impedance. The auto-zero cycle guarantees a zero display reading with a 0V input. The TC7117A features a precision, low-drift internal reference, and is functionally identical to the TC7117.