The TC7109A is a 12-bit plus sign， CMOS low power Analog-to-Digital Converter （ADC）。 Only eight passive components and a crystal are required to form a complete dual slope integrating ADC. The improved VOH source current and other TC7109A features make it an attractive per-channel alternative to analog multiplexing for many data acquisition applications. These features include typical input bias current of 1pA， drift of less than 1?V/°C， input noise typically 15?VP-P， and auto-zero. True differential input and reference allow measurement of bridge type transducers， such as load cells， strain gauges and temperature transducers. The TC7109A provides a versatile digital interface. In the Direct mode， Chip Select and HIGH/LOW byte enable control parallel bus interface. In the Handshake mode， the TC7109A will operate with industry standard UARTs in controlling serial data transmission – ideal for remote data logging. Control and monitoring of conversion timing is provided by the RUN/HOLD input and Status output. For applications requiring more resolution， see the TC500， 15-bit plus sign ADC data sheet. The TC7109A has improved over range recovery performance and higher output drive capability than the original TC7109. All new （or existing） designs should specify the TC7109A wherever possible.