Bypass Capacitor Requirements For FX2LP

Question: Are there any design guidelines for selecting the bypass capacitors required by CY7C68013A?

 

Answer:

Decoupling capacitors should be ceramic type of a stable dielectric. For lower value capacitance, it is appropriate to use Class 1 dielectric capacitors, C0G (also referred to as NPO). Class 2 X7R should be used for the larger values. It is

recommended that 0.01-µF and 0.001-µF capacitors be used to decouple supply pins nearest the pair of USB transceiver circuits. The 0.001-µF should be C0G dielectric. This will help decouple the power supply at the frequency range of highspeed USB switching. The other power supply pins should be decoupled with 0.1-µF X7R capacitors. It is important to have short trace runs for the power and ground connections from the EZ-USB FX2 component to solid power and ground planes.

The specific recommendation for the ceramic capacitor nearest each EZ-USB FX2 power pin is shown in the table below:

 

                                                                                                                                       
    QFN PIN NUMBER    CAPACITOR VALUE    QFN PIN NUMBER    CAPACITOR VALUE
    7    .01 uF    43    .1 uF
    11    .001 uF    55    .1 uF
    17    .1 uF    3    .1 uF
    27    .1 uF    3    .22 uF
    32    .1 uF