The EVAL-CN0335-PMDZ evaluation board circuit is a completely isolated 12-bit, 300 kSPS data acquisition system utilizing only three active devices. The system processes ±10 V input signals using a single 3.3 V supply. The total error after room temperature calibration is less than ±0.1% FSR over a ±10°C temperature change, making it ideal for a wide variety of industrial measurements.
The small footprint of the circuit makes this combination an industry-leading solution for data acquisition systems where the accuracy, speed, cost, and size play a critical role. Both data and power are isolated, thereby making the circuit robust to high voltages and also ground-loop interference often encountered in harsh industrial environments.
The circuit consists of an input signal conditioning stage, an ADC stage, and an output isolation stage. The ±10 V input signal is level shifted and attenuated by the U1A op amp that is one-half of the dual AD8606. The output of the op amp is 0.1 V to 2.4 V, which matches the input range of the ADC (0 V to 2.5 V) with 100 mV headroom to maintain linearity. The buffered voltage reference (VREF =2.5 V) from the ADC is used to generate the required offset.
The EVAL-CN0335-PMDZ circuit board uses the SDP-PMD-IB1Z and the EVAL-SDP-CB1Z system demonstration platform (SDP) evaluation board. The interposer board SDP-PMD-IB1Z and the SDP board EVAL-SDP-CB1Z have 120-pin mating connectors. The interposer board and the EVAL-CN0335-PMDZ board have 12-pin Pmod matching connectors, allowing quick setup and evaluation of the circuit’s performance. The SDP evaluation board is used with the CN0335 evaluation software to capture the data from the EVAL-CN0335-PMDZ circuit board.
Key Applications: Programmable Logic Controllers/ Distributed Control Systems