Data Sheet
WL1801MOD,
WL1805MO
D
,
WL1831MO
D
,
WL1835MOD
SWRS152M – JULY 2013 – REVISED OCTOBER 2017
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Applications, Implementation, and Layout
33
Copyright © 2013–2017, Texas Instruments Incorporated
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WL1835MOD
Table 7-1 lists the bill materials (BOM).
Table 7-1.
BOM
ITEM DESCRIPTION PART NUMBER PACKAGE REF. QTY
MFR
1 TI WL1835 Wi-Fi / Bluetooth module WL1835MODGI 13.4 x 13.3 x 2.0 mm U1 1
TI
2 XOSC 3225 / 32.768 kHz / 1.8 V /
±50 ppm
7XZ3200005 3.2 x 2.5 x 1.0 mm OSC1 1 TXC
3
Antenna / chip / 2.4 and 5 GHz / peak
gain > 5 dBi
ANT016008LCD2442MA1 1.6 mm x 0.8 mm ANT1, ANT2 2 TDK
6 Mini RF header receptacle U.FL-R-SMT-1 (10) 3.0 x 2.6 x 1.25 mm J5, J6 2 Hirose
7 Inductor 0402 / 1.1 nH / ±0.05 nH SMD LQP15MN1N1W02 0402 L1 1 Murata
8 Inductor 0402 / 1.5 nH / ±0.05 nH SMD LQP15MN1N5W02 0402 L2 1 Murata
9 Capacitor 0402 / 1.2 pF / 50 V / C0G /
±0.1 pF
GJM1555C1H1R2BB01 0402 C11 1 Murata
10 Capacitor 0402 / 2.2 pF / 50 V / C0G /
±0.1 pF
GJM1555C1H1R2BB01 0402 C9 1 Murata
11 Capacitor 0402 / 4 pF / 50 V / C0G /
±0.1 pF
GJM1555C1H4R0BB01 0402 C14 1 Murata
12 Capacitor 0402 / 8 pF / 50 V / C0G /
±0.1 pF
GJM1555C1H8R0BB01 0402 C13 1 Walsin
13 Capacitor 0402 / 10 pF / 50 V / NPO /
±5%
0402N100J500LT 0402 C5, C6 2 Walsin
14 Capacitor 0402 / 0.1 µF / 10 V / X7R /
±10%
0402B104K100CT 0402 C3, C4 1 Walsin
15 Capacitor 0402 / 1 µF / 6.3 V / X5R /
±10% / HF
GRM155R60J105KE19D 0402 C1 1 Murata
16 Capacitor 0603 / 10 µF / 6.3 V / X5R /
±20%
C1608X5R0J106M 0603 C2 1 TDK
7.1.2 Design Recommendations
This section describes the layout recommendations for the WL1835 module, RF trace, and antenna.
Table 7-2 summarizes the layout recommendations.
Table 7-2. Layout Recommendations Summary
ITEM
DESCRIPTION
Thermal
1 The proximity of ground vias must be close to the pad.
2 Signal traces must not be run underneath the module on the layer where the module is mounted.
3 Have a complete ground pour in layer 2 for thermal dissipation.
4 Have a solid ground plane and ground vias under the module for stable system and thermal dissipation.
5 Increase the ground pour in the first layer and have all of the traces from the first layer on the inner layers, if possible.
6 Signal traces can be run on a third layer under the solid ground layer, which is below the module mounting layer.
RF Trace and Antenna Routing
7 The RF trace antenna feed must be as short as possible beyond the ground reference. At this point, the trace starts to radiate.
8
The RF trace bends must be gradual with an approximate maximum bend of 45° with trace mitered. RF traces must not have sharp
corners.
9 RF traces must have via stitching on the ground plane beside the RF trace on both sides.
10 RF traces must have constant impedance (microstrip transmission line).
11
For best results, the RF trace ground layer must be the ground layer immediately below the RF trace. The ground layer must be
solid.
12 There must be no traces or ground under the antenna section.
13
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.