According to its manufacturer Maxim, the MAX11156 is the industry’s smallest 12-pin, 18-bit successive approximation register (SAR) analog-to-digital converter (ADC). Available in a tiny 3mm x 3mm TDFN package, the MAX11156 integrates an internal reference and reference buffer, saving cost and at least 70% board space over competing solutions. With 18-bit resolution and a 500ksps sampling rate, this high-performance ADC features Beyond-the-Rails technology, which supports a ±5V input from a single positive 5V input rail. This technology eliminates the need for negative power supplies and simplifies designs.
Due to its monotonic transfer characteristic, fast settling time, and lack of latency, the new ADC is ideal for fast, high-precision digital control-loop systems. It provides 18-bit resolution with no missing codes; excellent DC accuracy (0.5 LSB DNL and 2.5 LSB INL (typ)); and excellent AC performance (94.6dB SNR and -105dB THD (typ)). Additionally, the device communicates using a SPI-compatible serial interface, which can be used to daisy-chain multiple ADCs in parallel for multichannel applications. This interface can also provide a busy indicator to simplify system synchronization and timing.