Active production part — no end-of-life watch needed
Infineon continues to manufacture the PSoC 4 CY8C4100S series, and the part is ROHS3 compliant.
24 MHz Cortex-M0+ — enough throughput for sensor fusion and HMI
At 24 MHz, the ARM Cortex-M0+ core in this MCU is not a high-speed number-cruncher, but it is deliberately sized for the PSoC 4's strength: mixed-signal and human-interface control. The 32 KB Flash and 4 KB SRAM are enough for CapSense touch-scanning firmware, LCD segment drive, and a few serial protocol stacks without external memory.
Analog and peripheral set — CapSense, dual ADC, dual IDAC
The CY8C4125LQI-S433T integrates a 16-channel 10-bit slope ADC and a separate 16-channel 12-bit SAR ADC, plus two current-output IDACs. That combination handles both slow-scan touch sensing (slope ADC) and higher-resolution analog measurements (SAR ADC) on the same die. The CapSense block is the same hardware used across the PSoC 4 family, so firmware from a CY8C4245 project ports with minimal changes. Brown-out detect, LVD, POR, PWM, and WDT are all on-chip, reducing external supervisor IC count.
40-QFN package — thermal and layout notes
The 40-UFQFN with exposed pad (6x6 mm body) routes 34 I/O to the board. No special MSL derating is noted, but the standard MSL 3 floor-life window applies out of the bag.
Comparison to CY8C4245LQI-483 — speed and ADC count
The CY8C4245LQI-483 runs at 48 MHz (double the 24 MHz) and uses an older ARM Cortex-M0 core (not M0+), but shares the same 34 I/O, CapSense, and serial connectivity. The CY8C4125LQI-S433T has a richer ADC complement — 16x10b slope plus 16x12b SAR versus the 4245's 8x12b SAR only — making it a better fit for designs that need both touch and higher-resolution analog inputs. Both are active; the 4245 is a speed upgrade if the extra ADC channels are not needed.