Optical Module / AOC / DAC Reference Design
An illustrative optical module / AOC / DAC interconnect reference design for the data center / cloud layer of the five-layer network architecture, built around a host-side optical port interface board with three port types: SFP28 (1×2 cage + 25G connectors), QSFP28 (QSFP56 2×2 combo cage) and QSFP-DD (single-port cage + 76-pin connector). The same cage accepts optical modules, AOC active optical cables or DAC passive copper cables; a module management MCU reads CMIS / EEPROM to identify the cable type, and each port's 3.3V is filtered separately. 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 SFP28 port topology: the host's 25G SerDes TX / RX differential pairs pass AC-coupling capacitors (fitted as the SerDes requires; modules / AOCs are already AC-coupled internally) to TD± / RD± of the SFP28 connector; with a passive DAC copper cable the link runs directly to the far-end host, so enable SerDes equalization according to the cable length. Control and status lines go to I²C / GPIO, and 3.3V is filtered by a VOOHU molded inductor, one per port.
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 SFP28 ports | SFP28 ports · 1×2 ganged cage + 25G connectors | J1 J2 | SFP28 Series | WHSFP30412W009 | VOOHU |
| 02 | A SFP28 ports | SFP28 supply filter inductors ×2 | L1 L2 | Molded Inductors | WHYTA0420 series | VOOHU |
| 03 | B QSFP28 ports | QSFP28 ports · QSFP56 2×2 integrated cage + connector | J3 | QSFP56 Series | WH81161Y22121 | VOOHU |
| 04 | B QSFP28 ports | QSFP supply filter inductors ×4 | L3 L4 | Molded Inductors | WHYTA0420 series | VOOHU |
| 05 | C QSFP-DD port | QSFP-DD port · single-port cage + board connector | J4 | QSFPDD Series | WH81161Y00471 | VOOHU |
| 06 | C QSFP-DD port | QSFP-DD supply inductor | L5 | Molded Inductors | WHYT0630 Series | VOOHU |
| 07 | D Host IC / module management | Host FPGA / switch IC | U1 | — | — | Non-VOOHU |
| 08 | D Host IC / module management | Module management MCU + I²C multiplexer | U2 | — | — | Non-VOOHU |
| 09 | E 12V power | 12V power input | J5 | — | — | Non-VOOHU |
| 10 | E 12V power | Input TVS | D1 | — | — | Non-VOOHU |
| 11 | E 12V power | Power-line common-mode choke (EMI) | L6 | Power Line Common Mode Chokes | WHACM07A40R501 | VOOHU |
| 12 | E 12V power | Synchronous bucks ×3 | U4 U5 U6 | — | — | Non-VOOHU |
| 13 | E 12V power | Molded inductors ×3 (DC-DC) | L7 L8 L9 | Molded Inductors | WHYT0630 Series | VOOHU |
Resources & downloads
Board bill of materials
Reference designators, zones, VOOHU categories, recommended parts and availability for all 13 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 optical module / AOC / DAC reference design full package
Includes the full-board position list, datasheets for the recommended VOOHU parts and position-by-position selection notes. For selection advice tailored to your port type (SFP28 / QSFP28 / QSFP-DD / QSFP112), cage cooling and EMI fingers, or module power, please include it in your requirements. We reply within 24 hours on working days.
