MIKROE Load Cell 6 Click

Load Cell 6 Click is a compact add-on board representing a weigh scale solution. This board features the MAX11270, a high-performance 24-bit delta-sigma ADC that achieves excellent 130dB SNR while dissipating an ultra-low 10mW from Analog Devices. This SPI-configurable ADC sample rates up to 64ksps allow precision DC and AC measurements, with integral non-linearity guaranteed to 4ppm maximum. The MAX11270 offers a 6.5nV/√Hz noise programmable gain amplifier with gain settings between 1x to 128x. Optional buffers are also included to isolate the signal inputs from the switched capacitor sampling network, which allows the MAX11270 to be used with high-impedance sources without compromising the available dynamic range. This Click board™ is suitable for weight scale applications in various use cases.

Load Cell 6 Click is supported by a mikroSDK compliant library, which includes functions that simplify software development.

Load Cell 6 Click as its foundation uses the MAX11270, a pin programmable, ultra-low power 24-bit ΣΔ ADC that resolves a very high dynamic range from Analog Devices. The MAX11270 achieves excellent 130dB SNR while dissipating an ultra-low 10mW. It allows users to select a programmable gain amplifier with gain settings between 1x to 128x, unity-gain buffer, or connect signals directly to the delta-sigma sampling network. This ADC can resolve micro-volt level changes to the analog input, making it a good fit for seismic, instrumentation, and ATE applications.

The MAX11270 measures a pair of differential analog inputs (S+, S-) in buffered, direct connect, or PGA. The default configuration is directly connected, with PGA and input buffers powered down. These optional buffers isolate the signal inputs from the switched capacitor sampling network, which allows the MAX11270 to be used with high-impedance sources without compromising the available dynamic range. The ADC input range is programmable for unipolar (0 to VREF) ranges set by the reference voltage value obtained by the MAX6126, a 3V high-precision voltage reference, also routed to the E+ terminal.

Load Cell 6 Click communicates with MCU through a standard SPI interface that enables high clock speeds up to 5MHz. The MAX11270 is highly configurable via the internal registers, accessed via the SPI interface. It operates in two modes: Conversion mode or Register-Access mode selected by the command byte. Those registers include PGA gain selection, offset and gain calibration, and a scalable sample rate to optimize performance. It also offers software-selectable output data rates, up to 12.8ksps with no data latency and 64ksps continuous, to optimize data rate and noise.

In addition, it uses the Reset pin, routed to the RST pin of the mikroBUS™ socket, is used for a complete reset of all digital functions resulting in a Power-On reset default state, while the Data-Ready signal, labeled as RDY and routed to the INT pin of the mikroBUS™ socket, notifies the host MCU when the data is ready. The Sync Reset signal is also used, labeled as SYN, and routed to the PWM pin of the mikroBUS™ socket, which resets both the digital filter and modulator. It also has a GPIO header with two general-purpose pins from the MAX11270 which are user-configurable.

Even though this board uses both mikroBUS™ power rails, this Click board™ can only be operated with a 3.3V logic voltage level (5V is used only as a voltage reference power supply). The board must perform appropriate logic voltage level conversion before using MCUs with different logic levels. However, the Click board™ equipped comes equipped with a library containing functions and an example code that can be used, as a reference, for further development.

• Interface: SPI
• Compatibility: mikroBUS™
• Dimensions: 57.15 x 25.4mm
• Input Voltage: 3.3V, 5V
• Supply Voltage: 3.3V
• Analog Input Voltage Range: Min. 0V, Max. 3V
• Resolution: 24 bit
• Operating Temperature Range: Min. -40°C, Typ. +25°C, Max. +85°C