OLT (Central Office) Reference Design
An illustrative reference design for an OLT (central office) at the aggregation / edge layer of the five-layer network architecture (box-type OLT main board): 16 PON ports (SFP+ 2×8 cage-and-connector assemblies for XGS-PON / GPON OLT optical modules), 4 × 10G SFP+ uplinks (replaceable with 25G SFP28), an out-of-band MGMT port and a Console port, with the central-office −48V DC supply converted to an isolated 12V through a planar transformer. Each position is marked with the VOOHU parts available, recommended part numbers and package pinouts.
Illustrative PCB ⇄ Schematic
Illustrative top-side view arranged by functional zone (not the actual layout). Red numbered dots mark positions VOOHU can supply. Click a component on the board, an entry in the index below or a part in the schematic to see recommended parts and package pinouts on the right.
Illustrative PON port topology: each SerDes transmit / receive pair of the PON MAC connects through AC-coupling capacitors (fitted as the SerDes requires; the modules are AC-coupled internally) to TD± / RD± of the SFP+ 2×8 cage + connector assembly (J1), and the inserted XGS-PON / GPON OLT optical modules perform the optical-electrical conversion; I²C, TX_DISABLE, MOD_ABS and RX_LOS connect to the SoC's I²C / GPIO (PON modules also have burst-mode receive reset and other signals; connect them per the module datasheet). The modules' VccT / VccR are filtered from +3V3 by a VOOHU molded inductor and bypass capacitors, one per port. Each pair is drawn as one line; coupling capacitors and pull-ups are drawn as symbols without values.
Board bill of materials
Summarized by position; click any row to locate it on the board above.
| No. | Zone | Position | Ref. | VOOHU category | Recommended part | Availability |
|---|---|---|---|---|---|---|
| 01 | A PON ports | PON port SFP+ 2×8 cage + connector (one-piece) | J1 | SFP+ Series | WHSFP16228F028 | VOOHU |
| 02 | A PON ports | PON Vcc inductor ×16 | L1 L2 L3 L4 L5 L6 L7 L8 | Molded Inductors | WHYTA0420 series | VOOHU |
| 03 | B Optical uplinks | Uplink SFP+ 1×4 cage + 20-pin connector | J2 J3 J4 J5 | SFP+ Series | WH81-114-Y0006-1 | VOOHU |
| 04 | B Optical uplinks | Uplink optical module power filter inductors ×4 | L9 L10 L11 L12 | Molded Inductors | WHYTA0420 series | VOOHU |
| 05 | D PON MAC / switch | PON MAC / switch SoC | U1 | — | — | Non-VOOHU |
| 06 | D PON MAC / switch | DDR memory | U2 | — | — | Non-VOOHU |
| 07 | D PON MAC / switch | Flash | U3 | — | — | Non-VOOHU |
| 08 | C Management | MGMT RJ45 with integrated magnetics (out-of-band management port) | J6 | RJ45 with Integrated Magnetics | SYT211Q066CD2A4D | VOOHU |
| 09 | C Management | Management port Gigabit PHY | U4 | Ethernet PHY | JL2101C-NC | VOOHU |
| 10 | C Management | Console RJ45 | J7 | RJ45 Connector | WH56A11810011101 | VOOHU |
| 11 | C Management | RS-232 level shifter | U5 | — | — | Non-VOOHU |
| 12 | E −48V power | −48V power input terminals (A / B dual feeds) | J8 | — | — | Non-VOOHU |
| 13 | E −48V power | Bidirectional input TVS | D1 | TVS ESD | WHTB058VA | VOOHU |
| 14 | E −48V power | Input varistor (MOV) | RV1 | MOV | WHM0082VA | VOOHU |
| 15 | E −48V power | Power-line common-mode choke (EMI) | L13 | Power Line Common Mode Chokes | WHAL-9070A-301T0 | VOOHU |
| 16 | E −48V power | Isolated DC-DC controller | U6 | — | — | Non-VOOHU |
| 17 | E −48V power | Planar transformer (48V → 12V isolated) | T1 | Planar Transformers | WHPT-EQ200-025 | VOOHU |
| 18 | E −48V power | Synchronous buck ×2 | U7 U8 | — | — | Non-VOOHU |
| 19 | E −48V power | Molded inductors ×2 (DC-DC) | L14 L15 | Molded Inductors | WHYT0630 Series | VOOHU |
| 20 | E −48V power | Multiphase controller + DrMOS | U9 | — | — | Non-VOOHU |
| 21 | E −48V power | Combined inductors ×2 (multiphase VR) | L16 L17 | Combined Inductors | WHPBU-100710N-R15L0 | VOOHU |
Resources & downloads
Board bill of materials
Reference designators, zones, VOOHU categories, recommended parts and availability for all 21 positions. Opens directly in Excel.
Datasheet collection
Datasheet PDFs for the VOOHU parts recommended on this board.
Design files & footprint library
Schematic, PCB, and VOOHU part footprints and 3D models.
Coming soonRequest the OLT (Central Office) reference design full package
Includes the full-board position list, datasheets for the recommended VOOHU parts and position-by-position selection notes. For advice tailored to your PON port count, cage style (1×N / 2×N, with / without LEDs) or power scheme, describe it in your requirements. We reply within 24 hours on business days.
