eBUS is a serial 2-wire serial data-bus, often used in heating, solar energy, and other building automation systems. This project provides an interface to access an eBUS via USB. It uses a series transistor regulator circuit with a low IZT zener diode to extract the operating voltage from the eBUS, an ADuM1201 for the galvanic isolation, and a CH340N for the UART to USB conversion. Power consumption on the eBUS side is between 620uA (eBUS idle low/8V) and 920uA (eBUS idle high/24V), making the interface qualify as a class 0 device with respect to the eBUS specification. It has been designed to fit into an CNMB/1/2 2TE DIN rail enclosure by CAMDENBOSS. The interface is intended to be used with ebusd and can be used as a replacement for an eBUS Adapter v2.
When ordering at JLCPCB, remove the mouse bites and cut the boards yourself. Otherwise JLCPCB will charge you for two designs.
| Designator | Footprint | Quantity | Value | LCSC Part # |
|---|---|---|---|---|
| C1, C2 | C0805 | 2 | 10u | C15850 |
| C3, C4, C5, C6, C7, C8 | C0805 | 6 | 100n | C28233 |
| D1, D2 | SOT-23-3 | 2 | BAV99 | C2500 |
| D3 | SOT-123 | 1 | 5V6, Onsemi MMSZ4690* | C152307 |
| D4 | SOD-123 | 1 | 24V/1W, KDZVTR24B, MM1W24 | C209605, C438336 |
| D5 | SOD-123 | 1 | 7V5/1W, KDZVTR7.5B, MM1W7V5 | C209594, C382950 |
| D6, D7, D8 | D3.0mm | 3 | CHANZON 3mm diffused LED | |
| J1 | MSTBA_2,5_2-G-5,08 | 1 | MSTBA 2,5/2-G-5,08 | C3697 |
| J2, J5 | Molex_PicoBlade_53047-0210 | 2 | Molex 53047-0210 | C114130 |
| J3, J6 | Molex_PicoBlade_53047-0410 | 2 | Molex 53047-0410 | C504989 |
| J4 | HRO_TYPE-C-31-M-12 | 1 | HRO TYPE-C-31-M-12 | C165948 |
| Q1, Q2 | SOT-23-3 | 2 | BC817-40, S9013J3 | C52801, C6749 |
| R1 | R0805 | 1 | 0R | C17477 |
| R2, R3, R4, R11 | R0805 | 4 | 100K | C149504 |
| R5 | R0805 | 1 | 4K7 | C17673 |
| R6 | R0805 | 1 | 270K | C17589 |
| R7 | R0805 | 1 | 68K | C17801 |
| R8 | R0805 | 1 | 2M | C26112 |
| R9, R10 | R0805 | 2 | 5K1 | C27834 |
| R12, R13 | R0805 | 2 | 22K | C17560 |
| U1 | SO08 | 1 | AZV3002, TSX3702 | C5123396, C2970396 |
| U2 | SO08 | 1 | ADuM1201, π122U31 | C9669, C471590 |
| U3 | SO08 | 1 | CH340N, CH330N | C2977777 |
| U4 | SOT-23-6L | 1 | SRV05-4 | C85364 |
* Low IZT of 50uA is required. Other manufacturers than Onsemi may not qualify. For example, MMSZ4690 from Jiangsu Changjing Elec. Tech. is not recommened.