Complies with Directive 2002/95/EC (RoHS)
ETSI Compliant
I. Product Overview
The DR-TXC100-315 and DR-TXC100-433 Evaluation
Boards allow for evaluation of the RF performance of the
TXC100 300-450MHz Transmitter at 315 MHz and
433.92 MHz, respectively. The board is designed to
serve as a standalone evaluation platform or to be
incorporated on a user’s design simply by soldering
directly to the prototype PCB via standard .025” square
header pins. All configurable functions of the TXC100
are accessible for the user to directly interface to any
embedded microcontroller design.
The DR-TXC100 RF output uses an end launch SMA
connector for quick and convenient connection to an
external antenna or spectrum analyzer or the connector
may be removed and replaced with a
λ/4
monopole
antenna soldered to the center pin. The output is
optimized for two common frequencies of 315MHz and
433.92MHz. The 433.92MHz evaluation board is ETSI
compliant. All matching components are accessible for
optimization at other frequencies of interest.
The DR-TXC100 serves as a guide to PCB layout.
Placement and routing can be easily duplicated for quick
design-in and proven performance, speeding product
time-to-market and reducing
design efforts.
Evaluation Board
Electrical Characteristics
Characteristics
Operating Frequency
Modulation Types
ASK Data Rate
FSK Data Rate
Peak RF Output Power
Standby Current
Supply Voltage Range
Operating Temperature
V
DD
Ta
2.1
-40
+10
1
3.6
+125
Sym
fo
Min
300
OOK/ASK/
FSK
100
20
Kbps
Kbps
dBm
nA
Vdc
o
Typical
Max
450
Units
MHz
II. Key Features
Operating Frequency Range: 300-450 MHz
•
•
Modulation Types: OOK/ASK/FSK
•
Operation supply voltage: 2.1V - 3.6V
•
High Date rate:
ASK: 100 kbps
FSK: 20 kbps
•
Low current consumption:
ASK mode: 7 mA typical
FSK mode: 10 mA typical
•
Low Stand by current: < 1 nA
•
Adjustable Output power: -10dBm to +10dBm
•
Adjustable FSK Shift
•
Programmable Clock Output
C
Reference Crystal Parameters
Characteristics
Crystal Frequency
Load Capacitance
Motional Capacitance
Tolerance
Sym
fc
Cl
Cm
Tol
9
±30
Min
Typical
fo/32
3
10
Max
Units
MHz
pF
fF
ppm
RF Monolithics, Inc.
4441 Sigma Road
Dallas, Texas 75244
(800) 704-6079 toll-free in U.S. and Canada
www.rfm.com
Email: info@rfm.com
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III. Schematic Diagram
Table 1:
Bill of Material for the DR-TXC100
Ref Des
C4,C5,C9
C10*
C6
C11,C13
C12,C14
C8
C7
C1¹
C3¹
C2¹
L1¹²
L2¹²
R1
R2
Y1
315MHz Band
100pF
.01uF
DNP
1uF
.01uF
220pF
680pF
15pF
15pF
22pF
27nH
22nH
DNP
0 Ohm
9.84375
∞
433MHz Band
100pF
.01uF
DNP
1uF
.01uF
220pF
680pF
3.3pF
12pF
5.6pF
22nH
18nH
0 Ohm
DNP
13.560
◊
‡
¹Matching Components
²Use wirewound inductors ONLY for best performance
*
Install for External Reference ONLY
‡
ETSI COMPLIANT
∞
Hong Kong Crystal P/N SSL9843750E03FAFR800
◊
Hong Kong Crystal P/N SSM1356000E03FAFR800
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IV. Connections and Quick Start
Test Equipment Needed:
•
Spectrum Analyzer
•
Regulated, Variable Power Supply
•
Digital Multimeter (DMM)
Setup
1) Turn on power supply set to +3V and then turn off.
2) Connect GND lead to any GND pin.
3) Connect +lead of power supply to +input of DMM.
4) Connect COM lead of DMM to VCC of DR-TXC100.
5) Turn DMM to mA setting.
6) Connect the ANT connection (SMA connector) to the spectrum analyzer and set to 315MHz or 433.92MHz with Span
= 1MHz.
7) Turn on power supply. The spectrum analyzer should show a peak of about +10dBm at the set frequency (315MHz or
433.92MHz).
8) Observe the current draw on the DMM.
9) Vary the power supply from +2.1V to +3.6V and observe the output power vs. current.
V. Jumper Descriptions
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Jumpers
The DR-TXC100 functions can be tested by configuring the
jumper settings or applying external stimulus from a
pulse/function generator to pin 2 of the respective jumper.
Table 2 shows the jumper designations and associated functions.
NOTE: Pin 1 (VCC) denoted by square pad.
TABLE 2:
Jumper Designations
JUMPER
JP1
JP2
JP3
Position
1-2
2-3
1-2
2-3
1-2
2-3
1-2
2-3
1-2
2-3
1-2
2-3
1-2
2-3
1-2
2-3
Description
Data ‘1’
Data ‘0’
FSK Mode
ASK Mode
FreqDev(2) ‘1’
FreqDev(2) ‘0'
FreqDev(1) ‘1’
FreqDev(1) ‘0'
FreqDev(0) ‘1’
FreqDev(0) ‘0'
CLK(1) ‘1’
CLK(1) ‘0’
CLK(0) ‘1’
CLK(0) ‘0’
Enabled
Power Down
Data Pin
The TXC100 transmits ASK or FSK data at 100kbps and 20kbps,
respectively. JP1 controls whether a logic ‘1’ or logic ‘0’ is
applied. For ASK, a logic ‘1’ will turn on the power amplifier. For
FSK, a logic ‘1’ will shift the carrier to the higher deviation
frequency specified by JP3, JP4, JP5. For ASK, a logic ‘0’ will
turn off the power amplifier. For FSK, a logic ‘0’ will shift the
output to the fundamental carrier frequency. An external
modulating signal can be applied to JP1-2 by removing the
jumper and clipping onto the center pin directly and observing the
output modulation on the spectrum analyzer.
Mode Pin
Jumper JP2 sets the modulation mode, either ASK or FSK.
JP4
JP5
JP6
JP7
JP9
Deviation Setting
The FSK deviation is set by jumpers JP3-JP5. The position of these jumpers sets 1 of 8 possible deviation settings. The maximum
deviation is highly dependent on the crystal as is the carrier frequency desired. For 315MHz the max deviation is approximately
55kHz. For 433.92MHz the max deviation is approximately 80kHz. The frequency deviation is affected by the motional capacitance
of the crystal. For larger deviations, a crystal with a larger motional capacitance should be used. See Table 3 for jumper deviation
settings.
TABLE 3:
Jumper Deviation Settings
JP3 (bit2)
1-2
1-2
1-2
1-2
2-3
2-3
2-3
2-3
JP4 (bit1)
1-2
1-2
2-3
2-3
1-2
1-2
2-3
2-3
JP5 (bit0)
1-2
2-3
1-2
2-3
1-2
2-3
1-2
2-3
Logic
111
110
101
100
011
010
001
000
Description
Max Deviation
7/8 x Max Dev
3/4 x Max Dev
5/8 x Max Dev
1/2 x Max Dev
3/8 x Max Dev
1/4 x Max Dev
1/8 x Max Dev
Clock Output
The clock output frequency is set by jumpers JP6-JP7. The clock can be used for an on-board microcontroller or as an external
timing reference. The clock frequency is the crystal frequency divided by 4, 8, and 16. Table 4 shows the jumper setting to
configure the clock frequency.
TABLE 4:
Jumper Settings for Clock Frequency
JP6 (bit1)
1-2
1-2
2-3
2-3
JP7 (bit0)
1-2
2-3
1-2
2-3
Logic
11
10
01
00
Description
Xtal/16
Xtal/8
Xtal/4
Logic ‘0’ Output
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Chip Enable/Standby
The chip can be enabled or put into standby mode by setting jumper JP9. In standby mode the current usage drops to
<1nA for ultra low power standby. This pin is internally pulled low so removal of the shunt will automatically put the chip
in standby mode. To enable the chip place the shunt jumper across JP9(1-2).
External Reference Input
It is possible to input a custom reference frequency if it is not available as a standard crystal frequency. A test point is
provided to apply this frequency from an external source such as a low phase noise RF signal generator. The crystal
must be removed to inject this signal. Add .01uF capacitors to C5 and C10 and insert a 0-Ohm, 0603 resistor at C4.
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