A 12-pin, 18-bit successive approximation register (SAR) analogue-to-digital converter (ADC) is now being shipped by Maxim Integrated Products Inc. The company advises its MAX11156 integrates an internal reference and reference buffer, with the potential to save cost and at least 70 percent board space.
This ADC features Beyond-the-Rails technology, which supports a ±5V input from a single positive 5V input rail. This is claimed to eliminate the need for negative power supplies and simplifies designs. With 18-bit resolution and a 500ksps sampling rate, the device is ideal for automatic test equipment (ATE), industrial control systems, medical instrumentation, and robotics, where high accuracy and tiny size are paramount.
A combination of monotonic transfer characteristics, fast settling time, and lack of latency means this converter ideally fits fast, high-precision digital control-loop systems. In fact, the device provides 18-bit resolution with no missing codes; good DC accuracy (0.5 LSB DNL and 2.5 LSB INL (typ)); and good AC performance (94.6dB SNR and -105dB THD (typ)).
Also, this converter 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 synchronisation and timing.
Key Advantages include:
• Reduced board space: s small 18-bit SAR ADC integrates a reference buffer and internal reference, which saves cost and simplifies designs
• Improved performance: the 18-bit performance produces 94.6dB SNR, -105dB THD (typ), and guarantees no missing codes
• Bipolar input range: measures a ±5V (10VP-P) input range while operating from a single 5V supply; simplifies external signal conditioning
Maxim Integrated
