A Card Board PCBA is a printed circuit board assembly designed to manage secure data processing and connectivity in card-based systems, such as smart card readers or access control devices. It integrates ARM Cortex-M microcontrollers or ESP32 modules to handle encryption, authentication, and communication protocols like SPI, I2C, or CAN Bus. Built on FR4 substrates with ENIG/HASL finishes, these boards ensure reliable signal transmission and comply with RoHS and CE safety standards. Key features include ESD/surge protection, IP54-rated enclosures, and support for industrial temperature ranges (-20°C to +85°C). Applications range from contactless payment terminals to RFID-based security systems, prioritizing compact designs (e.g., 50mm × 50mm) and low-power operation (5–24V DC input) for IoT edge deployments.