The future in fast data transfers

Con­ven­tion­al tech­nolo­gies such as Flex­i­ble Flat Cable or Flex­i­ble Print­ed Cir­cuit (FFC/FPC) or micro-coax­i­al cable are increas­ing­ly reach­ing their lim­its as data trans­mis­sion rates between inter­nal­ly installed print­ed cir­cuit boards con­tin­ue to rise. Yamaichi Elec­tron­ics’ Y‑FLEX tech­nol­o­gy solves this prob­lem. With the high-speed FPC, data rates of 56 Gbps (PAM4) can be real­ized over a cable length of 100 mm.

The cable’s suit­abil­i­ty for high data trans­mis­sion rates is real­ized through var­i­ous fea­tures such as LCP (Liq­uid Crys­tal Poly­mer) as the base mate­r­i­al, the con­tact­ing of var­i­ous lay­ers with so-called sil­ver bumps and the spe­cial, 100 per­cent repro­ducible pro­duc­tion process. To achieve par­tic­u­lar­ly high trans­mis­sion rates, spe­cif­ic coor­di­na­tion with the FFC/FPC con­nec­tor used is important.

In prin­ci­ple, the mat­ing face can be adapt­ed to any stan­dard ZIF/non-ZIF/LIF con­nec­tor. How­ev­er, to achieve opti­mum per­for­mance, Yamaichi’s spe­cial­ly designed high-speed ZIF/non-ZIF con­nec­tors are most suit­able, e.g. the HF507 series.

In comparison: FFC and standard FPC

The biggest dif­fer­ence com­pared to FPCs is in the insu­la­tion mate­r­i­al. Unlike stan­dard poly­imides used in con­ven­tion­al FPCs, the LCP insu­la­tion mate­r­i­al of Y‑FLEX has a much low­er dielec­tric con­stant and pow­er fac­tor tan δ at high fre­quen­cies. As a result, atten­u­a­tion is sig­nif­i­cant­ly low­er and data trans­mis­sion rates are much high­er than stan­dard FPCs. In addi­tion, LCP has bet­ter hygro­scop­ic prop­er­ties than stan­dard poly­imides, which facil­i­tates pro­cess­ing and allows trace spac­ing and trace widths of less than 30 µm to be real­ized with the high­est accuracy.

In comparison: micro-coaxial cables

With this cable, trans­mis­sion stan­dards such as PCIe Gen 4 (16 GT/s), USB 3.2 Gen 2 (10 Gbps) or eDP HBR 3 (8.1 Gbps) can be achieved with­out hes­i­ta­tion. In the lat­est mea­sure­ments of the cur­rent gen­er­a­tion, even data rates of 56 Gbps (PAM4) were real­ized over a cable length of 100 mm. Due to the man­u­fac­tur­ing process (espe­cial­ly pre­ci­sion etch­ing and LCP mate­r­i­al as insu­la­tor) this tech­nol­o­gy is 100 per­cent reproducible.

All con­duc­tor tracks are com­plete­ly iden­ti­cal and thus achieve con­stant trans­mis­sion char­ac­ter­is­tics over the entire length. In coax­i­al cables, on the oth­er hand, the ratio of inner to out­er con­duc­tors varies along the cable because of the strand­ed structure.

When assem­bling the indi­vid­ual coax­i­al con­duc­tors to the con­nec­tor, there may also be dif­fer­ences in length and thus in the prop­a­ga­tion time of the indi­vid­ual lines.

Fit for future markets

A lead­ing man­u­fac­tur­er of mobile com­mu­ni­ca­tions and high-fre­quen­cy mea­sure­ment tech­nol­o­gy rec­og­nized this tech­nol­o­gy sev­er­al years ago and now uses it in a vari­ety of projects, such as 5G testers and body scan­ners. In addi­tion to mea­sure­ment tech­nol­o­gy, Y‑FLEX is used, for exam­ple, in autonomous vehi­cles, data net­work­ing, image pro­cess­ing and med­ical technology.