Tech Blog

How to choose USB 2.0 common mode inductor? This article explains the difference between common mode impedance and 90Ω differential impedance, differential insertion loss, connector-ESD-common mode inductor layout sequence, and establishes a board-level verification process using VOOHU 75Ω/90Ω/120Ω real material numbers.

What should I do if the SFP optical module cannot be pulled out? The most dangerous thing on site is not to temporarily stop the machine, but to continue to shake, clamp or pull it laterally when the lock has not been released. This can easily cause damage to the module pull ring, cage lock piece, front panel spring piece and even the board end connector. For truly effective troubleshooting, we should first distinguish the operating method, module unlocking mechanism, cage geometry, and overall machine assembly tolerances, and then decide whether to reinstall, shut down for disassembly, or iso

What is the difference between RJ11 6P4C and 6P6C? Starting from the number of contacts, RJ11 6P4C line sequence, 2×1 dual-port structure and PCB hole position, combined with VOOHU’s actual material number, we will explain how to choose the RJ11 connector.

How to choose RJ45 XLR self-locking connector for industrial equipment? Combined with VOOHU's real model, the pass-through and plug-in board structures, latches, panel stress and complete machine verification are analyzed.

Starting from the volt-second balance of the two half-cycles of the push-pull transformer, combined with four real on-shelf material numbers, the duty cycle asymmetry, flux bias, startup waveform, PCB symmetry and complete machine regression verification were sorted out.

Focusing on the WHSPE00467 board-end socket and WHSPE00468 crimp plug, the mating, crimping, differential channel, PoDL power supply and mass production wiring harness verification of the SPE connection system are explained.

Starting from the 350mA/600mA public screening field, the current definition, temperature rise path, multi-port thermal coupling and mass production verification method of PoE integrated magnetic RJ45 are explained.

Starting from module cross-testing, terminal contact, SMD solder joints, mechanical positioning and high-speed channels, the board-level inspection and mass production verification process of SFP intermittent links are established.

Starting from the network-by-network pin mapping, PCB library, isolation boundary and assembly process, the candidate screening, trial production and mass production verification methods when gigabit network transformers are migrated from DIP to SMD are explained.

Starting from the reference plane, mixed-mode port and fixture calibration, explain how to test the return loss, insertion loss and common mode characteristics of the Gigabit network transformer, and verify the link, PoE, temperature and insulation in a closed loop.

Starting from the panel-connector-PCB-chassis tolerance chain, explain how to check the opening direction, shielding shrapnel, LED and assembly boundaries of 1×2, 2×1, low-height and sinker RJ45.

Starting from the public on-shelf material numbers of SFP+ and SFP28 optical cages, we sort out the board-level verification boundaries of Press-Fit holes and tooling, light guide configurations, heat dissipation holes, and chassis assembly.