Infineon Technologies CY8C3865AXI-204

Overview

CY8C3865AXI-204 from Infineon Technologies (formerly Cypress Semiconductor) is a programmable System-on-Chip (PSoC® 3) integrating an 8-bit 8051 CPU, configurable analog/digital peripherals, 64 KB flash, 8 KB RAM, and full CAN 2.0b interface. It operates from 1.71–5.5 V across –40 to +85 °C, supports 67-MHz max clocking via internal PLL, and delivers ultra-low-power operation down to 200 nA in hibernate mode with RAM retention. Used in industrial sensor nodes requiring mixed-signal integration, real-time control, and fieldbus connectivity.

For engineers reviewing the CY8C3865AXI-204 datasheet, CY8C3865AXI-204 pinout, CY8C3865AXI-204 application, or CY8C3865AXI-204 equivalent, key selection criteria include its 67-MHz 8051 core, 24-channel DMA, 4× opamps, CapSense® support for up to 62 sensors, and native USB 2.0 Full-Speed peripheral interface with internal oscillator.

Technical Context

The CY8C3865AXI-204 implements a highly configurable architecture centered on a pipelined 8051 CPU with 32 interrupt inputs and hardware-accelerated digital signal processing via a 24-bit, 64-tap Digital Filter Block (DFB). Its routing fabric enables any analog or digital peripheral function-including four 16-bit TCPWM blocks, I²C, SPI, UART, LIN, and full CAN 2.0b-to be connected to any GPIO.

Analog subsystem flexibility includes a configurable 8–20-bit delta-sigma ADC, four 8-bit DACs, four comparators, four opamps, and programmable SC/CT blocks supporting PGA, TIA, mixer, and sample-and-hold functions-all referenced to a 1.024 V ±0.1% internal voltage reference. Clocking supports multiple sources: internal oscillators (1–100 kHz, 3–62 MHz), external crystals (4–25 MHz), PLL (up to 67 MHz), and 32.768-kHz watch crystal.

Key Specifications

Pinout & Package

The CY8C3865AXI-204 is housed in a 68-pin QFN package (7 mm × 7 mm, 0.5 mm pitch) with exposed thermal pad. Pin assignments are validated per Cypress Datasheet 001-11729 Rev. AH, Section 2 (Pinouts) and Section 3 (Pin Descriptions).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar programmable SoC applications.

Compared with CY8C3865AXI-204, the CY8C3866AXI-208 offers expanded I/O and package size for complex routing, while the CY8C4247AZI-M485 trades CAN/DFB capability for ARM compatibility and lower active power-making it suitable only where those legacy features are unnecessary.

Availability

CY8C3865AXI-204 is available at Aetrix Electronics and suitable for industrial sensor nodes, automotive body control modules, medical patient monitor front-ends, and smart home thermostat controllers requiring stable component supply and long-term lifecycle support.

Supply support for CY8C3865AXI-204 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Infineon Technologies acquired Cypress Semiconductor in 2020 and now owns and supports the full PSoC® portfolio, including legacy PSoC 3 devices. Infineon is a global semiconductor leader focused on power systems, automotive, industrial, and IoT applications.

The CY8C3865AXI-204 belongs to the PSoC® 3 family, designed specifically for ultra-low-power, mixed-signal embedded control in resource-constrained environments where analog precision, digital flexibility, and fieldbus connectivity (CAN/USB) must coexist on a single chip.

FAQ

Does CY8C3865AXI-204 support USB device functionality without an external crystal?

Yes. The device integrates an internal 48-MHz oscillator qualified for USB 2.0 Full-Speed (12 Mbps) operation, eliminating the need for an external crystal in USB peripheral applications. This oscillator meets USB timing jitter requirements per TID#40770053 certification, and is factory-trimmed to ±1% accuracy at 3 MHz.

What is the maximum number of CapSense® sensors supported on CY8C3865AXI-204?

The CY8C3865AXI-204 supports up to 62 CapSense® sensors using self-capacitance or mutual-capacitance methods. This capacity is enabled by dedicated hardware scan engines and programmable IDACs, allowing simultaneous scanning of all sensors in under 100 ms with built-in noise rejection algorithms.

Can the digital filter block (DFB) perform real-time IIR filtering on analog sensor data?

Yes. The 24-bit Digital Filter Block (DFB) supports both FIR and IIR filtering with up to 64 taps, programmable coefficients, and zero-latency pipeline operation. It can process streaming ADC data in real time-for example, applying a 4th-order IIR low-pass filter to ECG signals at 1 kSPS while leaving the 8051 CPU free for system tasks.

Is the 200-nA hibernate mode achievable with full RAM retention and wake-on-pin capability?

Yes. In hibernate mode, the CY8C3865AXI-204 retains full 8 KB RAM content while drawing only 200 nA typical. Wake events include any GPIO change, RTC alarm, or watchdog timeout. All wakeup sources retain state and restore CPU context within 1 µs upon exit, enabling rapid response to external stimuli.