User's Guide
Table Of Contents
- 1. WFM200 Pinout
- 2. Device Configuration
- 3. Features Description
- 4. Power Supplies
- 5. Application Schematic Recommendations
- 6. Typical Application Schematics
- 7. Layout Recommendations
- 7.1 Generic RF Layout Considerations
- 7.2 GND and RF Pads Including the Diversity Port and External Antennas
- 7.3 Module Antenna
- 7.3.1 Small Board Size Recommendations for Good RF Performance
- 7.3.2 Extended X Dimension Recommendation for Good RF Performance
- 7.3.3 Y Dimension (65 to 80 mm) Recommendation for Good RF Performance
- 7.3.4 Y Dimension (80 mm or Larger) Recommendation for Good RF Performance
- 7.3.5 WFM200 Portion One Corner Bias with 3 mm Metal Keep-Outs
- 7.3.6 Recommended Antenna Loop Trace Capacitor Values
- 7.4 WFM200 Reference Evaluation Board
- 8. Recommendations for Certification
- 9. Package Outline
- 10. Integral Antenna Loop and Keep-Out Required Dimensions
- 11. Recommended PCB Land Pattern
8.3 CE Certification Requirements
The Certification in CE Regions requires lower TX Power for the 1 Mbps and 2 Mbps 802.11b modulations. The amount of power re-
duction is based on the actual Max Gain specification of the Antenna used in the application. When the antenna gain reduces by 0.25
dB, the application may use 0.25 dB higher power settings for these two modulations. Use the PDS file for this purpose. The two affec-
ted modulations are in Mod_Group_0. This section provides the minimum amount of TX Power Back Off necessary in the PDS file for
Mod_Group_0 for specific channels, for a given Antenna Max Gain Specification. As stated in previous sections, the highest gain anten-
na allowed is 4.7 dBi. The first column in the table below shows the Specified Max Antenna Gain for the application in CE Regions. If
the exact value is not found, use the next higher gain specification provided in the table. The values to the right of the antenna gain are
the minimum values for TX Power Back Off in quarter dB steps, which are required to go into the PDS file for the given operating Wi-Fi
Channels. More back off than given here may be applied for other concerns.
CE Certified and Approved PDS File Minimum TX Power Back Off based on Antenna Max Gain Specification
Table 8.3. Required Minimum TX Power Back Off to Apply in PDS according to Maximum Antenna Gain
Antenna CE Minimum PDS File TX Power Back Off in quarter dB steps
Max Gain dBi CH1, CH2,
2412-2417 MHz
CH3-CH9,
2422-2452 MHz
CH10, CH11,
2457-2462 MHz
CH12, CH13,
2467-2472 MHz
4.7 8 11 9 5
4.45 7 10 8 4
4.2 6 9 7 3
3.95 5 8 6 2
3.7 4 7 5 1
3.45 3 6 4 0
3.2 2 5 3 0
2.95 1 4 2 0
2.7 0 3 1 0
2.45 0 2 0 0
2.2 0 1 0 0
1.95 0 0 0 0
Clear Channel Assessment must be configured in absolute mode to meet CE requirements.
This is achievable with Linux driver 2.2.4 by sending the following command to WFM200 after firmware download and before connect-
ing the the Access Point:
"sudo su" + "echo -en "\x0c\x00\x06\x04\x03\x20\x04\x00\x01\x00\x00\x00" > /sys/kernel/debug/ieee80211/
phy*/wfx/send_hif_msg"
UG395: WFM200 Hardware Design User's Guide
Recommendations for Certification
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