DAQ 3 Click as its foundation uses the ADAQ4003, a fast and precise system-in-package DAQ signal chain solution from Analog Devices. This μModule combines multiple standard signal processing and conditioning blocks into a single device containing a high bandwidth fully differential ADC driver, a low noise reference buffer, and an 18-bit SAR ADC along with selectable gain options. It can convert 2,000,000 samples per second (2 MSPS), achieving a high degree of specified accuracy. The ADAQ4003 also has a valid first conversion after being powered down for long periods to reduce the power consumed in applications where the ADC does not convert constantly.

The ADAQ4003 requires a supply voltage of 1.8V to work regularly. Therefore, a small regulating LDO, the ADP151 from Analog Devices, provides a 1.8V out of mikroBUS™ rails. In combination with LT3032, dual low noise positive and negative low dropout voltage linear regulator, it can generate regulated ±15 V positive and negative rails for any additional signal conditioning. This Click board™ also includes the LT6656, a precise voltage regulator that provides low noise and low drop out voltage reference of 4.096V. This feature intends to optimally drive the dynamic input impedance of the SAR ADC reference node.

DAQ 3 Click communicates with MCU using the 16-bit SPI serial interface compatible with standard SPI, QSPI™, MICROWIRE™, and digital signal processors (DSPs). The ADAQ4003 also has a Turbo mode allowing a slower SPI clock rate, making interfacing simpler. Turbo mode activates by writing to the configuration register and replaces the busy indicator feature when enabled. The ADAQ4003 can achieve the maximum throughput of 2 MSPS only with enabled Turbo mode and a minimum clock rate of 75 MHz.

An additional feature of this Click board™ represents specific settings related to a fully differential ADC driver like Power-Down Reference Buffer and Amplifier labeled as DRE and DAM routed on the RST and AN pins of the mikroBUS™ socket. Also, the ADC driver has one power mode pin labeled as MOD and routed on the PWM pin of the mikroBUS™ socket, which enables the full performance of the driver with this pin sets to its high logic state. On the other hand, the ADAQ4003 also uses INT pin as an interrupt, indicating that the conversion result is available on the SDO line of the SPI interface.

This Click board™ also comes with the jumpers labeled from JP2-JP8 required to achieve optimized performance with selectable gain options of 0.454, 0.909, 1, or 1.9. With jumpers labeled as JP4 and JP7 populated on the board, the default gain of the ADAQ4003 is set to 1. For more information about the correct jumper configuration when selecting gain, please consult the attached datasheet.

DAQ 3 Click possesses two SMA connectors labeled as IN- and IN+ that provide low noise analog signal sources. These inputs are fed and buffered with the LTC6373, a precision instrumentation amplifier with fully differential outputs that achieves excellent offset voltage, gain error, gain drift, and gain non-linearity. The user can easily program the gain to one of seven available settings through 3 slide switches labeled as GAIN SEL.

This Click board™ can operate with both 3.3V and 5V logic voltage levels selected via the VIO SEL jumper. This way, it is allowed for both 3.3V and 5V capable MCUs to properly use the SPI communication lines. However, the Click board™ comes equipped with a library containing easy-to-use functions and an example code that can be used, as a reference, for further development