ECG 7 Click is a compact add-on board that records the heart's electrical activity. This board features the MCP6N16, a single zero-drift instrumentation amplifier with selectable gain from Microchip. In addition to the jack connector provided for connecting the cable with ECG electrodes, this Click board™ offers the possibility of connecting electrodes through screw terminals or an onboard header if the electrode connection does not match the jack connector. Besides, the user is allowed to process the output signal in analog or digital form. This Click board™ is suitable for medical remote diagnostic equipment applications, such as electrocardiogram (ECG) measurement.

NOTE: This Click board™ represents a development and prototyping tool. It is not intended to be used for a patient's medical treatment and should not be used to diagnose or treat any conditions.

ECG 7 Click as its foundation uses the MCP6N16, a zero-drift instrumentation amplifier designed for single-supply operation with rail-to-rail input and output performance from Microchip. The design of the MCP6N16 is based on a current feedback architecture which allows for the output voltage to be independently set regardless of the input common-mode voltage. Its internal offset correction gives high DC precision, low offset and drift, and negligible noise.

The head part of the board represents a differential amplification stage based on the MCP6N16, with the RC input filter providing a low-pass function for differential mode signals. This part also comes with selectable gain for the MCP6N16, performed by an onboard switch marked as GAIN, allowing users to quickly set the gain on the MCP6N16 to either 101V/V or 301V/V by setting the switch to an appropriate position. After that, the signal from MCP6N16 goes through amplification and buffering by the MCP6002 operational amplifier. Then the signal is ready for further processing in analog or digital format.

As mentioned before, this Click board™ possesses two ways to communicate with the MCU. The output voltage of the MCP6002 Op-Amp can be converted to a digital value using MCP3221, a successive approximation A/D converter from Microchip, using a 2-wire I2C compatible interface, or can be sent directly to an analog pin of the mikroBUS™ socket labeled as AN. Selection is performed by onboard SMD switch labeled as VOUT SEL to an appropriate position marked as AN and ADC. Using MCP3221 and I2C interface, data transfers at rates of up to 100kbit/s in the Standard and 400kbit/s in the Fast Mode.

In addition to the 3.5mm jack connector reserved for connecting the ECG/EMG cable with ECG electrodes, this Click board™ offers the possibility of connecting electrodes through screw terminals labeled as VIN+ and VIN-, or unpopulated header if the electrode connection does not match the jack connector.

This Click board™ can operate with both 3.3V and 5V logic voltage levels selected via the VCC SEL jumper. This way, it is allowed for both 3.3V and 5V capable MCUs to use the communication lines properly. 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.

• Interface: Analog, I²C
• Compatibility: mikroBUS™
• Dimensions: 57.15 x 25.4mm
• Input Voltage: 3.3V or 5V
• Operating Temperature Range: Min. -40°C, Typ. +25°C, Max. +120°C

• Schematic
• MCP3221 Datasheet
• MCP6002 Datasheet
• MCP6N16 Datasheet
• mikroSDK
• GitHub