NCN5121 is a receiver−transmitter IC suitable for use in KNXtwisted pair networks (KNX TP1−256). NCN5121 embeds both PHY and MAC layers and handles the transmission and reception of data on the bus. It generates from the unregulated bus voltage stabilized voltages for its own power needs as well as to power external devices. NCN5121 assures safe coupling to and decoupling from the bus. Various monitors (bus voltage, current, temperature...) are made available through an analog pin.

• KNX certified TP transceiver with embedded PHY and MAC layers (TP1-256) . 9600 Bauds communication speed.
• Two high efficient DC-DC converters + one linear regulator :
• - DC-DC1 : fixed 3.3 V
• - DC-DC2 : adjustable between 1.2 and 21 V
• - 20V linear regulator
• Bus Current Consumption up to 24 mA
• Supervision of temperature, KNX bus voltage and current
• Control and monitoring of power regulators
• Buffering of sent data frames (extended frames upported)
• Selectable UART/SPI interface and baud rate to host controller.
• Comprehensive clocking system
• - Operates with industry standard low cost 16 MHz quartz
• - Can generate 8/16 MHz clock for the external MCU
• Extended ambient temperature range -40 C to +105 C