This user's guide describes how to use the TI WL1835MODCOM8B board to evaluate the performance of
the TI WL18MODGB module.
Related Documentation From Texas Instruments
•TI WiLink8 Single-Band Combo Module – Wi-Fi, Bluetooth, and BLE (SWRS152)
•WiLink 8 Wiki: http://www.ti.com/wilink8wiki
If You Need Assistance
The primary sources of WL18MODGB information are the device-specific data sheets and user’s guides.
For the most up-to-date version of the user’s guide and data sheets, go to
http://www.ti.com/product/wl1835mod.
Warning
The WL1835MODCOM8B board is tested to comply with ETSI/R&TTE over temperatures from –20 to
+70°C.
This board should not be modified to operate in other frequency bands other than what they are designed
for.
FCC Licensing Requirements for EVM’s Wifi and Bluetooth Radio Module:
For evaluation only; not FCC approved for resale. This kit is designed to allow:
1. Product developers to evaluate electronic components, circuitry, or software associated with the kit to
determine whether to incorporate such items in a finished product
2. Software developers to write software applications for use with the end product. This kit is not a
finished product and when assembled may not be resold or otherwise marketed unless all required
FCC equipment authorizations are first obtained. Operation is subject to the condition that this product
not cause harmful interference to licensed radio stations and that this product accept harmful
interference. Unless the assembled kit is designed to operate under part 15, part 18, or part 95 of this
chapter, the operator of the kit must operate under the authority of an FCC license holder or must
secure an experimental authorization under part 5 of this chapter.”
Per TI’s Regulatory Compliance Information located in the WL1835ModCOMB8A User’s Guide’s
“Evaluation Board/Kit/Module (EVM) Additional Terms,” this EVM cannot be used for production purposes
and is explicitly restricted from end-product introduction.
Use of this EVM requires the developer to provide a minimum distance of at least 20 cm from the antenna
to all persons in order to minimize risk of potential radiation hazards.
Industry Canada Licensing Requirements:
The radio module is Industry Canada certified, but does not apply to the EVM. This EVM is not authorized
for sale or use inCanada unless special provisions are arranged between developer and Industry Canada.
Preface
SWRU359C–September 2013–Revised January 2014
Read This First
CAUTION
Do not leave the EVM powered when unattended.
SWRU359C–September 2013–Revised January 2014Preface
The WL1835MODCOM8B device is a WiFi®MIMO, Bluetooth, and Bluetooth Low Energy (BLE) module
board with the TI WL18MODGB module. WL18MODGB is built-in TI WL1835 IEEE 802.11 b/g/n and
Bluetooth 4.0 solutions to provide the best WiFi and Bluetooth coexistence interoperability and powersaving technologies from TI.
1.1Features
•WLAN, Bluetooth, BLE on a module board
•100-pin board card
•Dimension 76.0 mm(L) x 31.0 mm(W)
•WLAN 2.4 GHz SISO (20- and 40-MHz channels), 2.4-GHz MIMO (20-MHz channels)
•Support for BLE dual mode
•Seamless integration with TI Sitara and other application processors
•Design for TI AM335X general-purpose EVM
•WLAN and Bluetooth, BLE cores are software and hardware compatible with prior WL127x, WL128x
and CC256x offerings, for smooth migration to device.
•Shared HCI transport for Bluetooth and BLE over UART and SDIO for WLAN.
•WiFi / Bluetooth single antenna co-existence
•Built-in chip antenna
4
WL1835MODCOM8B WLAN MIMO and Bluetooth®Module Evaluation Board SWRU359C–September 2013–Revised January 2014
for TI Sitara™ Platform
1The proximity of ground vias must be close to the pad.
2Signal traces must not be run underneath the module on the layer where the module is mounted.
3Have a complete ground pour in layer 2 for thermal dissipation.
4Have a solid ground plane and ground vias under the module for stable system and thermal dissipation.
5
6
SWRU359C–September 2013–Revised January 2014 WL1835MODCOM8B WLAN MIMO and Bluetooth®Module Evaluation Board
Submit Documentation Feedback
Increase the ground pour in the first layer and have all of the traces from the first layer on the inner layers, if
possible.
Signal traces can be run on a third layer under the solid ground layer, which is below the module mounting
layer.
Figure 21 shows layer 1 with the trace to the antenna over ground layer 2.
Layout Guidelines
Figure 20. Trace Design for the PCB Layout
Figure 21. Layer 1 Combined With Layer 2
Table 3, Figure 22, and Figure 23 describe instances of good layout practices for the antenna and RF
trace routing.
Table 3. Antenna and RF Trace Routing Layout Guidelines
ReferenceGuideline Description
1
2
3RF traces must have via stitching on the ground plane beside the RF trace on both sides
4RF traces must have constant impedance (microstrip transmission line).
5
6There must be no traces or ground under the antenna section.
7
SWRU359C–September 2013–Revised January 2014 WL1835MODCOM8B WLAN MIMO and Bluetooth®Module Evaluation Board for
Submit Documentation Feedback
The RF trace antenna feed must be as short as possible beyond the ground reference. At this point, the trace
starts to radiate.
The RF trace bends must be gradual with an approximate maximum bend of 45 degrees with trace mitered. RF
traces must not have sharp corners.
For best results, the RF trace ground layer must be the ground layer immediately below the RF trace. The
ground layer must be solid.
RF traces must be as short as possible. The antenna, RF traces, and modules must be on the edge of the PCB
product. The proximity of the antenna to the enclosure and the enclosure material must also be considered.
Figure 24 describes the MIMO antenna spacing. The distance of ANT1 and ANT2 must be greater than
half of wavelength (62.5 mm @ 2.4 GHz).
The supply routing guidelines are as follows:
•For power supply routing, the power trace for V
•The 1.8-V trace must be at least 18 mil wide.
•Make V
•If possible, shield V
The digital signals routing guidelines are as follows:
•SDIO signals traces (CLK, CMD, D0, D1, D2, and D3) should be routed in parallel to each other and
•SDIO Clock, PCM clock… These digital clock signals are a source of noise. Keep the traces of these
Layout Guidelines
Figure 24. MIMO Antenna Spacing
must be at least 40 mil wide.
BAT
traces as wide as possible to ensure reduced inductance and trace resistance.
BAT
traces with ground above, below, and beside the traces.
BAT
as short as possible (less than 12 cm). In addition, every trace length must be the same as the others.
There should be enough space between traces – greater than 1.5 times the trace width or ground – to
ensure signal quality, especially for the SDIO_CLK trace. Remember to keep them away from the
other digital or analog signal traces. TI recommends adding ground shielding around these buses.
signals as short as possible. Whenever possible, maintain a clearance around them.
SWRU359C–September 2013–Revised January 2014 WL1835MODCOM8B WLAN MIMO and Bluetooth®Module Evaluation Board
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