Specifications

Product Technical Specification & Customer Design Guidelines
Interfaces
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This document is the sole and exclusive property of WAVECOM. Not to be distributed or divulged without
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WA_DEV_Q64_PTS_001-003 January 9, 2009
3.20.3 Application
A typical schematic is shown below:
Figure 43: Example of USB implementation
Recommended components:
 R1: 1MΩ
 C1, C3 : 100nF
 C2, C4 : 2.2μF
 D1 : STF2002-22 from SEMTECH
 U1 : LP2985AIM 3.3V from NATIONAL SEMICONDUCTOR
The regulator used is a 3.3V one. It is supplied through J1 when the USB wire is
plugged.
The EMI/RFI filter with ESD protection is D1. The D1 integrated pull up resistor used
to detect full speed is not connected as it is embedded in the Wireless CPU
®
.
R1 and C1 must be close to J1.