AN0903

TRC103 915 MHz Transceiver Reference Design
Introduction
This application note presents a PCB reference design for RFM’s TRC103 transceiver IC operating in the
902 to 928 MHz band. The reference design includes an integrated PCB antenna. The reference design
schematic is shown in Figure 1 below.
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Figure 1 - TRC103 915 MHz Reference Design Schematic
Note the dot (band) orientation of L1 with respect to L2, and the orientation of L4 with respect to L5.
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AN0903 - 06/21/10
Bill of Materials
The TRC103 915 MHz Reference Design BOM is presented below:
U1
U2
Y1
L1
L2
L3
L4
L5
L6
L7
L8
C1
C2
C3
C4
C5
C6
C7
C8
C9
C10
C11
C12
C13
R1
R2
PCB
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©2010 by RF Monolithics, Inc.
RFM TRC103 Transceiver IC
RFM RF2040E Low-loss SAW Filter
RFM XTL1020 Crystal, 12.80000 MHz
5.6 nH ±5%, 0603 RF inductor
5.6 nH ±5%, 0603 RF inductor
RF Bead, 300 ohm, Fair Rite 2506033017Y0, 0603
8.2 nH ±5%, 0603 RF inductor
8.2 nH ±5%, 0603 RF inductor
100 nH ±5%, 0603 RF inductor
18 nH ±5%, 0603 RF inductor
zero ohm resistor, 0603
1,000 pF ±5%, COG, 50 V, 0603 capacitor
0.0068 µF ±10%, X7R, 50 V, 0603 capacitor
0.1 µF ±10%, X5R, 50 V, 0603 capacitor
47 pF ±5%, COG, 50 V, 0603 capacitor
0.047 µF ±10%, X7R, 50 V, 0603 capacitor
100 pF ±5%, COG, 50 V, 0603 capacitor
not used
0.22 µF ±10%, X7R, 50 V, 0603 capacitor
1 µF ±10%, X5R, 50 V, 0603 capacitor
1 µF ±10%, X5R, 50 V, 0603 capacitor
10 µF ±10%, Tantalum, 16 V, B case capacitor
not used
3.3 ± 0.25 pF, COG, 50 V, 0603 capacitor
6.8K ±5%, 0.1 W, 0603 film resistor
1 ohm ±5%, 0.1 W, 0603 film resistor
see www.rfm.com/products/apnotes/trc103_pcb.zip
Technical support +1.800.704.6079
E-mail: info@rfm.com
Page 2 of 7
AN0903 - 06/21/10
Circuit Board Layers
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Figure 2 - Top Assembly
Figure 2 shows the TRC103 reference design top assembly. Power supply and digital I/O signals are organized on the left, the printed antenna is on the right. Note the dot (band) orientation of L1 with respect
to L2, and the orientation of L4 with respect to L5. A wide variety of microcontrollers can be used to control the TRC103. PADs PCB design files and Gerber files of the reference design layout are available at
www.rfm.com/products/apnotes/trc103_pcb.zip.
Figure 3 - Top Silkscreen
The top silkscreen is shown in Figure 3.
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©2010 by RF Monolithics, Inc.
Technical support +1.800.704.6079
E-mail: info@rfm.com
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AN0903 - 06/21/10
Figure 4 - Top Solder Mask
The top solder mask is shown in Figure 4.
Figure 5 - Top Etch
The top etch pattern is shown in Figure 5. Using ±5% COG RF capacitors where specified in the bill of
materials is important to reference design performance.
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©2010 by RF Monolithics, Inc.
Technical support +1.800.704.6079
E-mail: info@rfm.com
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AN0903 - 06/21/10
Figure 6 - Drill & Layer Data
The drill and layer data is provided in Figure 6. The reference design is implemented on a two-sided
0.031 inch board with 1 ounce copper traces.
Figure 7 - Bottom Etch
Figure 7 shows the reference design bottom etch pattern.
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©2010 by RF Monolithics, Inc.
Technical support +1.800.704.6079
E-mail: info@rfm.com
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AN0903 - 06/21/10
Figure 8 - Bottom Solder Mask
Figure 8 shows the reference design bottom solder mask.
Figure 9 - Bottom Silkscreen
Figure 9 shows the bottom silkscreen.
www.RFM.com
©2010 by RF Monolithics, Inc.
Technical support +1.800.704.6079
E-mail: info@rfm.com
Page 6 of 7
AN0903 - 06/21/10
Figure 10 shows the assembled TRC103 915 MHz reference design PCB.
Figure 10 - Assembled Reference Design PCB
Reference Design Range Testing
The TRC103 915 MHz reference design achieves a typical range of 1200 feet (365 meters) in “open field”
conditions 3.5 feet (1 meter) off the ground, using a data rate of 50 kb/s.
www.RFM.com
©2010 by RF Monolithics, Inc.
Technical support +1.800.704.6079
E-mail: info@rfm.com
Page 7 of 7
AN0903 - 06/21/10