User's Manual

Page 11 of 31
Signals offered
by
USB interface
The name of the correlative
pins in
Mini PCIe Interface
SN. of the Mini
PCIe Interface
Description
USB_VBUS .3VAUX 2, 24, 39, 41,52 USB power
DM USB_DM_IN 36 USB Data-
DP USB_DP_IN 38 USB Data+
GND GND 4, 9, 15, 18,21, 26, 27,
29, 34, 35, 37, 40, 43,
50
GND
2.2.3.2 Reference circuit
The reference circuit of USB interface is shown in figure 2-7.
1）For getting the steady-going USB power supply, it is recommended that a 10uF（C406）filter capacitor and a 22pF
（C407）filter capacitor should be used.
2）For reducing the BER of USB transmission, it is recommended to add a resistor with values below 10Ω to the
DM and DP in USB interface. Just like the resistors R408 and R409 in figure 2-7.
3）For avoiding the electro-static in USB interface, it is recommended to use the ESD element. Just like the voltage
dependent resistors RV406, RV407 and RV408 with the static capacitance values below 3pF.
Figure 2-7 The reference circuit of USB interface