The AD4190-4 is a low noise, completely integrated analog front end for high precision measurement applications. The device contains a low noise, 24-bit Σ-Δ analog-to-digital converter (ADC) and can be configured to have four differential or eight single-ended or pseudodifferential inputs. The on-chip low-noise gain stage ensures that signals of small amplitude can be interfaced directly to the ADC.
The AD4190-4 offers the highest degree of signal chain integration. The device contains an internal reference and accepts two external differential references, which can be internally buffered. Other key integrated features include:
- Programmable gain amplifier (PGA). Due to the programmable gain (0.5 to 128), the PGA allows direct interfacing to transducers with low output amplitudes such as resistive bridges, thermocouples, and resistance temperature detectors (RTDs).
- The PGA has a wide common-mode input range, which gives designers a greater margin for widely varying input common modes.
- Low drift, well matched precision current sources. Use the excitation current sources to excite 2-, 3-, and 4-wire RTDs or bridge type sensors. Excitation current output options include 10μA, 50μA, 100μA, 250μA, 500μA, 1mA, and 1.5mA. The currents can also be added if higher currents are required.
- Use the low-side power switch (PDSW) to power down bridge sensors between conversions.
- Voltage bias for thermocouples (the VBIAS source sets the common-mode voltage of a channel to (AVDD + AVSS)/2.
- The smart sequencer allows the conversion of each enabled preconfigured channel in a predetermined order, which allows a mix of transducer, system checks, and diagnostic measurements to be interleaved. The sequencer eliminates the need for repetitive serial interface communication with the device to change configuration. Configure the 16-channels in the sequence. Each of these chann
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