Data Sheet
Table Of Contents
- 1 Design guidelines
- 2 Ordering Information
- 3 Pinout and Terminal Descriptions
- 4 Packaging
- 5 Power control
- 6 Interfaces
- 7 Block diagram
- 8 Example schematics
- 9 802.11 Radio
- 10 Firmware
- 11 Host interfaces
- 12 Electrical characteristics
- 13 RF Characteristics
- 14 Physical dimensions
- 15 Layout guidelines
- 16 Soldering recommendations
- 17 Certifications
- 18 Qualified Antenna Types for WF121-E
Silicon Labs
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having a gain greater than the maximum gain indicated for that type, are strictly prohibited for use with this
device. See table 25 for the approved antennas for WF121-E and WF121-N.
OEM Responsibilities to comply with FCC and Industry Canada Regulations
The WF121 Module has been certified for integration into products only by OEM integrators under the
following conditions:
• The antenna(s) must be installed such that a minimum separation distance of 20cm is maintained
between the radiator (antenna) and all persons at all times.
• The transmitter module must not be co-located or operating in conjunction with any other antenna or
transmitter.
As long as the two conditions above are met, further transmitter testing will not be required. However, the
OEM integrator is still responsible for testing their end-product for any additional compliance requirements
required with this module installed (for example, digital device emissions, PC peripheral requirements, etc.).
IMPORTANT NOTE: In the event that these conditions cannot be met (for certain configurations or co-location
with another transmitter), then the FCC and Industry Canada authorizations are no longer considered valid
and the FCC ID and IC Certification Number cannot be used on the final product. In these circumstances, the
OEM integrator will be responsible for re-evaluating the end product (including the transmitter) and obtaining a
separate FCC and Industry Canada authorization.
End Product Labeling
The WF121 Module is labeled with its own FCC ID and IC Certification Number. If the FCC ID and IC
Certification Number are not visible when the module is installed inside another device, then the outside of the
device into which the module is installed must also display a label referring to the enclosed module. In that
case, the final end product must be labeled in a visible area with the following:
“Contains Transmitter Module FCC ID: QOQWF121”
“Contains Transmitter Module IC: 5123A-BGTWF121”
or
“Contains FCC ID: QOQWF121
“Contains IC: 5123A-BGTWF121”
The OEM of the WF121 Module must only use the approved antenna(s) described in table 25, which have
been certified with this module.
The OEM integrator has to be aware not to provide information to the end user regarding how to install or
remove this RF module or change RF related parameters in the user manual of the end product.
To comply with FCC and Industry Canada RF radiation exposure limits for general population, the
antenna(s) used for this transmitter must be installed such that a minimum separation distance of
20cm is maintained between the radiator (antenna) and all persons at all times and must not be co-
located or operating in conjunction with any other antenna or transmitter.