The TC7135 4-1/2 digit analog-to-digital converter (ADC) offers 50 ppm (1 part in 20,000) resolution with a maximum nonlinearity error of 1 count. An auto-zero cycle reduces zero error to below 10 V and zero drift to 0.5 V/C. Source impedance errors are minimized by a 10 pA maximum input current. Roll-over error is limited to 1 count. By combining the TC7135 with a TC7211A (LCD) or TC7212A (LED) driver, a 4-1/2 digit display DVM or DPM can be constructed. Overrange and underrange signals support automatic range switching and special display blanking/flashing applications. Microprocessor-based measurement systems are supported by BUSY, STROBE, and RUN/HOLD control signals. Remote data acquisition systems with data transfer via UARTs are also possible. The additional control pins and multiplexed BCD outputs make the TC7135 the ideal converter for display or microprocessor-based measurement systems.