Analyse The Electrical Performance Of High Speed Type-C Connector

In the time of prevalence of electronic devices,USB(Universal Serial Bus)is the most used interface.But with the USB standard constantly updated,the original variety of USB interface has could not meet the requirements.So,USB Type-C connector came into being.The Type-C connector not only solves the problem of forward and reverse plugging of the USB interface,but also results in a smaller footprint on the device compared to the smaller size of the Type-A and Type-B connectors.At the same time,more power supply capability and faster transfer speed also makes it more and more popular.From the current trend,with the future of the USB standard constantly updating,there will be more and more devices support Type-C interface,and the speed must be fast.Reliability and signal integrity issues from small size and high speed of Type-C connector should be more attention.This topic analyze the DC performance of Type-C connector through the combination of theoretical calculation and test analysis,and analyzes the signal integrity of Type-C connector by combining simulation analysis and test.First,the DC contact performance of Type-C connector under normal and corrosive environment was analyzed.The contact resistance of Type-C connector was measured by four-point method.The corrosion resistance of contact pair was analyzed by electron microscope/energy spectrum analyzer.The contact resistance of 67%contacts is less than or equal to 40m? under normal conditions.In corrosive environment,the contact resistance is more than twice that of the normal environment,depending on whether the connector mated or detached.When connectors in the plug the corrosion resistance is not good and the surface had corrosive with high resistivity,increased contact resistance and affect the contact reliability.Although the plug connector can make the corrosive shedding,the contact performance can no longer be restored to the corrosion before.Then,the signal integrity parameters of Type-C connector are simulated and analyzed in three-dimensional electromagnetic field simulation software Ansoft HFSS.The signal integrity of row B pin is also better than row A.Signal integrity of pin B signal integrity meet the requirements and pin A in the transmission rate more than 7GHz does not meet the standard.Single differential model simple structure compared with complete model had better signal integrity.In the HFSS,single differential pair models of connector with different insertion depths and different permittivity dielectric layers are established.The factors affecting the signal integrity of the connector are analyzed to optimize the design.The signal integrity is also better when insertion depth less and the signal integrity is best when the dielectric constant of dielectric layer is 3.8.Finally,the Type-C connector was analyzed by eye in CST Microware Studio and the eye diagrams parameters at 5GHz and 10GHz were obtained.Finally,Type-C connectors were tested for signal integrity.According to the characteristics of Type-C connectors,PCB clamps are selected as the test fixture.The traces are microstrip line and differential structure,and match the 85? differential impedance of Type-C connector,The test fixture needed to make the PCB layout of the test fixture in Altium Designer.This topic uses E5071C type vector network analyzer to test the connector impedance,insertion loss and return loss.The test results of impedance and return loss are close with simulation results and the insertion loss simulation results were significantly higher than the test results.There are two main reasons for the discrepancy between the simulation results and the test results:(1)There is a certain difference between the simulation model and the physical structure parameters and the working environment;(2)The unevenness of the welding spot and the dielectric layer of the test fixture can lead to errors.