MicroBCU2

MicroBCU2
Developer	SirSydom
Status	beta
Version	V00.20
Microcontroller/Board	universal

Description

A Bus Coupler Unit (BCU) / KNX Transveiver which supplies the connected device with power from KNX Bus and provides a bus interface at OSI Layer 2.

Hardware

• IC: NCN5120 (ready for NCN5121 / 5130)
• Size: 23 x 19 x 9 mm
• Voltage 1: 3.3V
• Voltage 2 (optional): 5V (default), can be changed: 3.3V - 21V
• Max. current: up to 100mA
• UART: 19200bps 8E1 / 3.3V

User Documentation

Soldering the Kit

MicroBCU2 comes as a kit where the big parts on the bottom side have to be soldered:

• C4 - 100µF / 35V electrolytic capacitor. Polarization is important, refer to silkscreen or photo
• C41 - 1µF MLCC 1206
• L1 and L2 - 220µH inductors
• R1 - 22R resistor 2512
• J1 - 7x1 2.54 pin header (or whatever you need to connect to your host PCB)
• D1 - SS16 reverse polarity protection diode. . Polarization is important, refer to silkscreen. The bar on the diode should match the bar on silkscreen.
• D2 - SMAJ40CA TVS diode

I recommend to solder the parts in this order: L1, L2, C4, C41, R1, D1, D2, J1

Links

Vorstellungs- / Entwicklunsthread im KNX User Forum [1]