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HUAWEI MC509 CDMA LGA Module
Hardware Guide
Description of the Application Interfaces
Issue 01 (2011-04-08)
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
34
The USB interface is powered directly from the 3.3 V supply. The USB input/output lines are
compatible with the USB 2.0 3.3 V signal specifications.
Table 3-10 DC Electrical Characteristics of USB
VOHmin
VOLmax
VIHmin
VILmax
2.8V
0.3V
2V
0.8V
Figure 3-8 Recommended circuit of USB interface
Since the USB interface of MC509 module supports USB 2.0 full speed, the resistance
“RV102 and RV103” in the 0must 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 full speed protocol, with differential lining and impedance
control to 90 ohm
It is recommended that set USB D+ and USB D- pins as test points and then place these
test points on the DTE for debug.