ARM Cortex-M0+ at 24 MHz — entry-level 32-bit compute with programmable analog
The Infineon CY8C4125AZI-S433T is a PSoC 4 MCU built around a 32-bit ARM Cortex-M0+ core clocked at 24 MHz. The part is part of the CY8C4100S series, Infineon's entry-level PSoC 4 family that trades some CPU throughput and memory density for a lower BOM cost compared to the 48 MHz CY8C42xx siblings. What sets this device apart from a plain Cortex-M0+ MCU is the integrated programmable analog and digital fabric. On the analog side you get a 10-bit slope ADC (16 channels), a 12-bit SAR ADC (16 channels), and two current-mode IDACs. The digital subsystem includes a CapSense block for touch sensing, plus PWM timers and a watchdog timer. The supply range spans 1.71 V to 5.5 V on a single rail, so the part can run directly from a 3.6 V Li-ion cell or a 5 V industrial supply without an external LDO.
CapSense and analog integration — what it saves on the BOM
The CapSense peripheral is a hardware touch-sensing engine that handles self-capacitance and mutual-capacitance scanning without CPU intervention during the measurement cycle. For a capacitive touch interface — buttons, sliders, proximity — this eliminates a dedicated touch controller IC and the associated serial-communication overhead. The 16-channel 12-bit SAR ADC and the two IDACs can serve as a front-end for resistive sensors, thermistors, or simple current-loop outputs, again reducing external analog components. The slope ADC (10-bit, 16 channels) is a lower-accuracy, lower-power option suitable for battery-voltage monitoring or coarse sensor thresholds. The 12-bit SAR ADC covers the higher-resolution needs. Both share the same pin-mux, so the firmware selects the appropriate converter per channel.
48-TQFP package — layout and thermal notes
The 48-TQFP (7×7 mm) has a 0.5 mm pitch, which is a standard fine-pitch QFP that routes easily on a two-layer board with 6/6 mil trace/space rules. There is no exposed thermal pad — the package dissipates through the leadframe and the 48 leads. For continuous operation near the 85°C upper limit with all I/O switching, ensure adequate copper area on the inner-layer ground plane under the package. Mounting is surface-mount only. MSL level is not listed in this record, but PSoC 4 devices typically carry MSL 3; verify the moisture sensitivity on the bag label before reflow.
It is ROHS3 compliant.