IN Brief:
- The MTCH3380P supports 38 self-capacitance or 64 mutual-capacitance sensors, while MTCH3240P supports 24 or 32.
- Twelve parallel ADCs acquire multiple sensor signals at once to limit scanning delays.
- The controllers support operation up to 105°C and customer-led IEC/UL 60730 Class B certification.
Microchip Technology has introduced the MTCH3380P and MTCH3240P capacitive-touch controllers, combining 12 parallel analogue-to-digital converters with dedicated touch processing to support buttons, sliders and wheels in display-free human-machine interfaces. The devices are intended for industrial equipment, appliances and outdoor electronic systems where large sensor arrays, protective covers and electrical noise can complicate reliable touch detection.
The MTCH3380P accommodates up to 38 self-capacitance sensors or 64 mutual-capacitance sensors, while the MTCH3240P supports 24 or 32 respectively. Both use 12 parallel analogue-to-digital converters to acquire several sensor channels during the same period, avoiding a wholly sequential scan of each sensing element.
Capacitive-touch controls detect changes in an electric field caused by a finger or another suitable conductive object approaching a sensing electrode. The controller measures the change in capacitance and interprets the signal according to the layout and configuration. In self-capacitance mode, capacitance of an individual electrode is measured relative to a reference, whereas mutual-capacitance sensing measures coupling between transmitting and receiving electrodes.
For sliders and wheels, a controller combines signals from adjacent electrodes to estimate touch position and interpret movement. A slider or wheel requires the controller to resolve changes across multiple sensing elements, often using relative signal strengths to estimate position. Response depends on timing and quality of measurements as well as processing that converts them into an interaction event.
Scanning sensors in sequence can extend acquisition time as electrode counts rise; Microchip instead employs 12 ADCs working in parallel. If each measurement occupies part of a repeated scanning cycle, adding sensors can extend the interval before all channels have been sampled. Microchip addresses that constraint with 12 ADCs in parallel, allowing data from several channels to be acquired during the same period and reducing the acquisition-time penalty associated with larger interfaces.
Parallel acquisition changes how the analogue front end can be organised, but its contribution to performance must be considered alongside signal processing and the electrical characteristics of the sensor layout. Electrode dimensions, routing, cover materials and environmental interference influence signal-to-noise ratio. The controller must distinguish intentional events from changes caused by nearby circuitry, external electrical fields, temperature variation and other conditions.
Microchip has designed the devices for operation through relatively thick protective covers and when users are wearing gloves, two conditions that reduce measurable changes in capacitance. A thicker cover places additional material between electrode and finger, weakening coupling on which detection depends. Glove materials can further alter coupling, so reliable operation requires suitable sensitivity, electrode geometry and noise rejection.
These constraints occur in control panels for ovens, cooktops, washing machines and industrial equipment where surfaces must withstand cleaning, moisture or repeated handling. Outdoor installations such as electric vehicle chargers, parking meters and kiosks introduce further demands because protective materials and environmental variation can affect sensing. Microchip identifies these applications as intended uses, although the final interface must still be evaluated with its cover and sensor construction.
Both controllers support operating temperatures up to 105°C, extending the thermal range for equipment installed near heat sources. The devices also support customer development towards IEC/UL 60730 Class B functional safety certification. That provision assists system developers working within appliance safety requirements, but does not establish that every completed product using the controller is automatically certified. Surrounding hardware, software and application safety functions remain part of certification.
Microchip provides mTouch Studio and evaluation hardware for electrode configuration and bench testing, alongside Linux and Zephyr host drivers for integration with application processors. The controller handles capacitance measurement and touch interpretation, allowing the main system to receive events without implementing the entire sensing algorithm.
A dedicated touch controller can handle electrode acquisition and event interpretation while the host processor continues running application logic or communications. The touch controller supplies information about interactions while the host determines how equipment responds. Designers must still account for communication timing, error handling and behaviour when sensor conditions fall outside expected range.
Microchip lists MTCH3380P at prices starting from $1.06 and MTCH3240P from $0.80, both at quantities of 10,000 units. They are available through Microchip and authorised distributors, with development resources intended to support evaluation before production design is finalised. Suitability for a control panel depends on electrode arrangement, protective material, interference and response requirements.
