Abstract: A double-sided and multilayer flexible printed circuit (FPC) substrate contains: a body, multiple tilted vias passing through the body, a sputtering layer, multiple conductive portions, and multiple copper circuit layers. The sputtering layer is adhered on the body and the multiple tilted vias. A respective conductive portion is formed in a respective titled via and is connected with the sputtering layer. The multiple copper circuit layers are located on a top and a bottom of the body and are connected with the sputtering layer, and the multiple copper circuit layers are connected via the multiple conductive portions.

Abstract: The present utility model relates to an ultra-low voltage two-stage ring voltage-controlled oscillator applied to a chip circuit. The oscillator includes two-stage delay units. The oscillator includes two delay units that are connected end-to-end, and adjusts a working frequency by adjusting delay time of the delay unit. The delay unit includes PMOS transistors M1, M2, M3, and M4, NMOS transistors M5, M6, M7, and M8, and a load capacitor CL. The two-stage ring voltage-controlled oscillator of the present utility model uses a substrate feed forward bias structure, reduces a threshold voltage of a transistor, reduces a supply voltage, reduces power consumption, has a large tuning range, and is particularly suitable for a system that works at a low supply voltage.