Usb Interface - Huawei ME909 Series Hardware Manual

HUAWEI ME909 Series LTE LGA Module
Hardware Guide

3.6 USB Interface

The ME909 is compliant with USB 2.0 High speed protocol. The USB interface is
powered directly from the VBAT supply. The USB signal lines are compatible with the
USB 2.0 signal specifications. Figure 3-14 shows the circuit of the USB interface.
Table 3-8 Definition of the USB interface
Pin No.
85
86
According to USB protocol, for bus timing or electrical characteristics of ME909 USB
signal, please refer to the chapter 7.3.2 of
Figure 3-14 Recommended circuit of USB interface
Issue V0.3 (2013-05-21)
Pin Name
USB_DM
USB_DP
 Since the USB interface of ME909 module supports USB 2.0 high speed, the resistance
"RV102 and RV103" in the Figure 3-14 must be Voltage Sensitive Resistor with small
capacitance (ALVC18S02003 manufactured by AMOTECH or B72590T7900V60
manufactured by EPCOS is recommended.). In addition, The layout design of this circuit on
the DTE board should comply with the USB 2.0 high speed protocol, with differential lining
and impedance control to 90 Ω
 It is recommended that set USB_DM and USB_DP pins as test points and then place these
test points on the DTE for debugging. But layout stub should not be generated.
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Description of the Application Interfaces
I/O Description
I/O USB data signal D-
I/O USB data signal D+
Universal Serial Bus Specification 2.0.
DC Characteristics (V)
Min. Typ. Max.
- - -
- - -
33