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Not recommended for new designsTH71081 868/915MHz ASK Transmitter / LO Source Features
Fully integrated, PLL-stabilized VCO Frequency range from 850 MHz to 920 MHz ASK achieved by on/off keying of internal power amplifier FM possible with external varactor Wide power supply range from 2.2 V to 5.5 V High over-all frequency accuracy Very low standby current Adjustable output power range from -15 dBm to +1 dBm Adjustable current consumption from 6.2 mA to 12.5 mA Differential output well-suited for loop antenna Conforms to EN 300 220 and similar standards 8-pin Small Outline Integrated Circuit (SOIC)
Ordering Information
Part No. TH71081 Temperature Code E (-30 C to 85 C) Package Code DC (SOIC8)
Application Examples
Keyless car and central locking Low-power telemetry Alarm and security systems General digital data transmission General analog audio signal transmission Local oscillator signal generation
Pin Description
LF 1 RO 2 ENTX 3 PS/DATA 4 TH71081
8 VEE 7 OUT1 6 OUT2 5 VCC
General Description
The TH71081 ASK transmitter IC is designed for applications in the European 868MHz industrial-scientificmedical (ISM) band, according to the EN 300 220 telecommunications standard. It can also be used for any other system with carrier frequencies ranging from 850 MHz to 920 MHz (e.g. for applications in the US 915MHz ISM band). The transmitter's carrier frequency fc is determined by the frequency of the reference crystal fref that is used. The integrated PLL synthesizer ensures that each RF value, ranging from 850 MHz to 920 MHz, can be achieved by using a crystal with reference frequency according to: fref = fc/N, where N = 32 is the PLL feedback divider ratio.
3901071081 Rev. 009
Page 1 of 12
Data Sheet May/05
Not recommended for new designsTH71081 868/915MHz ASK Transmitter / LO Source Document Content
1 Theory of Operation ...................................................................................................3
1.1 General................................................................................................................................. 3 1.2 Block Diagram ...................................................................................................................... 3
2
Functional Description ..............................................................................................4
2.1 ASK Modulation.................................................................................................................... 4 2.2 Frequency Modulation .......................................................................................................... 4 2.3 LO Source ............................................................................................................................ 4 2.4 Mode Control Logic .............................................................................................................. 4
3 4
Pin Definition and Description ..................................................................................5 Electrical Characteristics ..........................................................................................6
4.1 Absolute Maximum Ratings.................................................................................................. 6 4.2 Normal Operating Conditions ............................................................................................... 6 4.3 Crystal Parameters............................................................................................................... 6 4.4 DC Characteristics................................................................................................................ 7 4.5 AC Characteristics................................................................................................................ 7 4.6 Output Power Selection........................................................................................................ 7
5
Test Circuit .................................................................................................................8
5.1 Test circuit component list to Fig. 2 ...................................................................................... 8
6 7 8 9 10
Spectrum Plots...........................................................................................................9 Package Information ................................................................................................10 Reliability Information..............................................................................................11 ESD Precautions ......................................................................................................11 Disclaimer .................................................................................................................12
3901071081 Rev. 009
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Data Sheet May/05
Not recommended for new designsTH71081 868/915MHz ASK Transmitter / LO Source 1 Theory of Operation
1.1 General
As depicted in Fig.1, the TH71081 transmitter consists of a fully integrated voltage-controlled oscillator (VCO), a divide-by-32 divider (div32), a phase-frequency detector (PFD) and a charge pump. An external loop filter at pin LF determines the dynamic behaviour of the PLL and suppresses reference spurious signals. The VCO's output signal feeds the power amplifier (PA). RF signal power Po can be adjusted in six steps from Po = -15 dBm to +1 dBm either by changing the value of resistor R1 or by varying the voltage VPS at pin PS/DATA. The open-collector differential output (OUT1, OUT2) can be used to either directly drive a loop antenna or to be converted to a single-ended impedance by means of a balanced-to-unbalanced (balun) transformer. For maximum available output power, the differential output should be matched to a load of about 1 k. Bandgap biasing ensures stable operation of the IC at a power supply range of 2.2 V to 5.5 V.
1.2
Block Diagram
VCC 5
PS/DATA 4
div32 XOSC RO 2 CX1 XTAL charge pump PFD VCO
PA
OUT1 7 OUT2 6 VCC
mode control
ENTX 3
LF CF1 RF1
1
8 VEE
CF2
Fig. 1: Block diagram with external components
3901071081 Rev. 009
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Data Sheet May/05
Not recommended for new designsTH71081 868/915MHz ASK Transmitter / LO Source 2 Functional Description
2.1 ASK Modulation
The TH71081 can be ASK-modulated by applying data directly at pin PS/DATA. This turns the PA on and off and therefore leads to an ASK signal at the output.
2.2
Frequency Modulation
For FM operation an external varactor is required. It simply acts as a pulling capacitor connected in series to the crystal. Then the analog modulation signal, applied through a series resistor, directly modulates the XOSC.
2.3
LO Source
Many applications require a stable RF source. For this purpose, the TH71081 can be used without modulation as an easy-to-use, PLL-stabilized, continuous wave (CW) generator.
2.4
Mode Control Logic
The mode control logic allows two different modes of operation as listed in the following table. The mode control pin ENTX is pulled-down internally. This guarantees that the whole circuit is shut down if this pin is left floating. ENTX 0 1 Mode TX standby TX active Description TX disable TX enable
3901071081 Rev. 009
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Data Sheet May/05
Not recommended for new designsTH71081 868/915MHz ASK Transmitter / LO Source 3 Pin Definition and Description
Pin No. 1 LF Name I/O Type analog I/O
LF 1
200 200
Functional Schematic
Description connection to loop filter, charge pump output, VCO tuning input
5p
2
RO
analog I/O
37k
RO 2
28p
XOSC connection to XTAL, Colpitts type crystal oscillator
28p
3
ENTX
input
ENTX 3
1.1k
mode control input, CMOScompatible with internal pull-down
4
PS/DATA
analog I/O
20A
power-select and ASK input, high-impedance comparator logic TX standby: IPS = 0 TX active: IPS = 20A positive power supply
PS/DATA 4
200
5 6
VCC OUT2
supply output
VCC VCC
differential power amplifier output, open collector
OUT2
OUT1 7
7
OUT1
output
6
differential power amplifier output, open collector
VEE VEE
VEE
8
VEE
ground
negative power supply
3901071081 Rev. 009
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Data Sheet May/05
Not recommended for new designsTH71081 868/915MHz ASK Transmitter / LO Source 4 Electrical Characteristics
4.1 Absolute Maximum Ratings
Parameter Supply voltage Input voltage Storage temperature Junction temperature Thermal Resistance Power dissipation Electrostatic discharge 1) all pins except OUT1, OUT2 Symbol VCC VIN TSTG TJ RthJA Pdiss VESD1 VESD2 human body model, 1) human body model, 2) -1.0 -0.75 Condition Min 0 -0.3 -65 Max 7.0 VCC+0.3 150 150 163 0.12 +1.0 +0.75 Unit V V C C K/W W kV
2) pins OUT1, OUT2
4.2
Normal Operating Conditions
Parameter Symbol VCC TA VIL VIH fref fc ENTX pin ENTX pin set by the crystal fc = 32 * fref TA < 70C, VCC 2.5V 0.7*VCC 26.5 850 28.75 890 920 40 6 5 Condition Min 2.2 -30 Max 5.5 85 0.3*VCC Unit V C V V MHz MHz
Supply voltage Operating temperature Input low voltage CMOS Input high voltage CMOS XOSC frequency VCO frequency
Data rate ASK FM deviation Modulation frequency FM
RASK fFM fmod
NRZ
kbit/s kHz kHz
4.3
Crystal Parameters
Parameter Symbol f0 CL C0 R1 Condition fundamental mode, AT Min 26.5 10 Max 28.75 15 7 40 Unit MHz pF pF
Crystal frequency Load capacitance Static capacitance Resonance resistance
3901071081 Rev. 009
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Data Sheet May/05
Not recommended for new designsTH71081 868/915MHz ASK Transmitter / LO Source
4.4 DC Characteristics
all parameters under normal operating conditions, unless otherwise stated; typical values at TA = 23 C and VCC = 3 V Parameter Standby current Operating current Input current Pull down current Pull up current Symbol ISBY ICC IIN IPD IPS Condition ENTX=0 ENTX=1, VPS=1.1V ENTX=0 ENTX=1 ENTX=1 7 -1 3 14 8 20 Min Typ 0.05 9.5 Max 0.1 14 1 30 24 Unit A mA A A A
4.5
AC Characteristics
all parameters under normal operating conditions, unless otherwise stated; typical values at TA = 23 C and VCC = 3 V; ENTX = 1, VPS=1.1V, fc = 868.3 MHz, test circuit shown in Fig. 2 Parameter Output power Reference spurs Harmonic content Spurious output signal VCO gain Charge pump current Start-up time Symbol Po Pref Pharm Poff KVCO ICP ton from "TX standby" to "TX active" mode @ fc fref @ 2fc , 3fc , 4fc VPS 0.1V Condition Min Typ -2 -44 -40 -60 300 260 1.0 1.2 Max Unit dBm dBm dBm dBm MHz/V A ms
4.6
Output Power Selection
typical values at TA = 23 C and VCC = 3 V: ENTX = 1, fc = 868.3 MHz, test circuit shown in Fig. 2 R1 / k R2 / k VPS / V Icc / mA Po / dBm Pharm / dBm 2 12.5 1 -40 0 7.5 4.7 1.1 9.5 -2 -40 11 4.7 0.9 8.5 -5 -40 15 4.7 0.7 7.8 -8 -45 24 4.7 0.5 7.0 -10 -45 43 4.7 0.3 6.2 -15 -50
If the transmitter is operated at any supply voltage Vcc, the values for R1 and R2 can be calculated as allows:
V R1 = R2 * cc - 1 V PS
3901071081 Rev. 009
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Data Sheet May/05
Not recommended for new designsTH71081 868/915MHz ASK Transmitter / LO Source 5 Test Circuit
L2 L3 OUT
6 8 7 5
L1 C1
C4
C2
C3
C5
OUT1
OUT2 ENTX 3
1
2
CX RF1 CF2 CF1 XTAL
R2 R1 C6
4
PS DATA 12 12 DATA GND
RO
LF
12 3
Fig. 2: Test circuit for ASK with 50 matching network
VCC ENTX GND VCC GND
5.1
Test circuit component list to Fig. 2
Size
0603 0603 0603 0603 0805 0805 0603 0603 0805 0603 0603 0603 0603 0603 0603 HC49/S
Part
CF1 CF2 CX C1 C2 C3 C4 C5 C6 L1 L2 L3 RF1 R1 R2 XTAL
Value
4.7 nF 56 pF 18 pF 0.68 pF 33 pF 2.2 pF 330 pF 330 pF 33 nF 8.2 nH 15 nH 22 nH 1.0 k see para. 4.6 see para. 4.6 27.1344 MHz
Tolerance
10% 10% 5% 5% 5% 5% 5% 10% 10% 5% 5% 5% 10% 10% 10% 30ppm calibr. 30ppm temp.
Description
loop filter capacitor loop filter capacitor XOSC capacitor, note 1 impedance matching capacitor impedance matching capacitor impedance matching capacitor blocking capacitor blocking capacitor blocking capacitor impedance matching inductor impedance matching inductor impedance matching inductor loop filter resistor ASK power-select resistor, not requirement at CW mode ASK or CW mode power-select resistor fundamental wave crystal, CL = 12 pF, C0, max = 7 pF, R1 = 40
Note 1: value depending on crystal parameters
3901071081 Rev. 009
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VCC
VEE
Data Sheet May/05
Not recommended for new designsTH71081 868/915MHz ASK Transmitter / LO Source 6 Spectrum Plots
All plots depict TH71071`s typical performance at VCC = 3.0 V and TA = 23 C, derived with the test circuit shown in Fig. 2.
Fig. 3: RF output signal and spurious emissions, CW mode
Fig. 4: Single-sideband phase noise at 500 kHz offset, CW mode
Fig. 5: ASK modulation with RASK = 4 kbit/s NRZ 3901071081 Rev. 009 Page 9 of 12 Data Sheet May/05
Not recommended for new designsTH71081 868/915MHz ASK Transmitter / LO Source 7 Package Information
D 7 ZD e
8
E
H
1 B
DETAIL - A
L
DETAIL - A 0.38 x 45 BSC (0.015x45)
A
A2
.10 (.004)
Fig. 6: SOIC8 (Small Outline Integrated Circuit)
all Dimension in mm, coplanarity < 0.1mm D min max min max 4.80 4.98 0.189 0.196 E 3.81 3.99 H 5.80 6.20 A 1.52 1.72 A1 0.10 0.25 A2 1.37 1.57 1.27 e B 0.36 0.46 0.014 0.050 0.018 0.021 0.53 ZD C 0.19 0.25 0.075 0.098 L 0.41 1.27 0.016 0.050 0 8 0 8
all Dimension in inch, coplanarity < 0.004" 0.150 0.2284 0.060 0.0040 0.054 0.157 0.2440 0.068 0.0098 0.062
3901071081 Rev. 009
A1
C
Page 10 of 12
Data Sheet May/05
Not recommended for new designsTH71081 868/915MHz ASK Transmitter / LO Source 8 Reliability Information
This Melexis device is classified and qualified regarding soldering technology, solderability and moisture sensitivity level, as defined in this specification, according to following test methods: * * * * * * IPC/JEDEC J-STD-020 Moisture/Reflow Sensitivity Classification For Nonhermetic Solid State Surface Mount Devices (classification reflow profiles according to table 5-2) EIA/JEDEC JESD22-A113 Preconditioning of Nonhermetic Surface Mount Devices Prior to Reliability Testing (reflow profiles according to table 2) CECC00802 Standard Method For The Specification of Surface Mounting Components (SMDs) of Assessed Quality EIA/JEDEC JESD22-B106 Resistance to soldering temperature for through-hole mounted devices EN60749-15 Resistance to soldering temperature for through-hole mounted devices MIL 883 Method 2003 / EIA/JEDEC JESD22-B102 Solderability
For all soldering technologies deviating from above mentioned standard conditions (regarding peak temperature, temperature gradient, temperature profile etc) additional classification and qualification tests have to be agreed upon with Melexis. The application of Wave Soldering for SMD's is allowed only after consulting Melexis regarding assurance of adhesive strength between device and board. Based on Melexis commitment to environmental responsibility, European legislation (Directive on the Restriction of the Use of Certain Hazardous substances, RoHS) and customer requests, Melexis has installed a Roadmap to qualify their package families for lead free processes also. Various lead free generic qualifications are running, current results on request. For more information on manufacturability/solderability see quality page at our website: http://www.melexis.com/html/pdf/MLXleadfree-statement.pdf
9 ESD Precautions
Electronic semiconductor products are sensitive to Electro Static Discharge (ESD). Always observe Electro Static Discharge control procedures whenever handling semiconductor products.
3901071081 Rev. 009
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Data Sheet May/05
Not recommended for new designsTH71081 868/915MHz ASK Transmitter / LO Source 10 Disclaimer
Devices sold by Melexis are covered by the warranty and patent indemnification provisions appearing in its Term of Sale. Melexis makes no warranty, express, statutory, implied, or by description regarding the information set forth herein or regarding the freedom of the described devices from patent infringement. Melexis reserves the right to change specifications and prices at any time and without notice. Therefore, prior to designing this product into a system, it is necessary to check with Melexis for current information. This product is intended for use in normal commercial applications. Applications requiring extended temperature range, unusual environmental requirements, or high reliability applications, such as military, medical lifesupport or life-sustaining equipment are specifically not recommended without additional processing by Melexis for each application. The information furnished by Melexis is believed to be correct and accurate. However, Melexis shall not be liable to recipient or any third party for any damages, including but not limited to personal injury, property damage, loss of profits, loss of use, interrupt of business or indirect, special incidental or consequential damages, of any kind, in connection with or arising out of the furnishing, performance or use of the technical data herein. No obligation or liability to recipient or any third party shall arise or flow out of Melexis' rendering of technical or other services. (c) 2002 Melexis NV. All rights reserved.
For the latest version of this document. Go to our website at
www.melexis.com
Or for additional information contact Melexis Direct:
Europe and Japan:
Phone: +32 1367 0495 E-mail: sales_europe@melexis.com
All other locations:
Phone: +1 603 223 2362 E-mail: sales_usa@melexis.com
ISO/TS 16949 and ISO14001 Certified 3901071081 Rev. 009 Page 12 of 12 Data Sheet May/05

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