EVB7107 MELEXIS | Alldatasheet
Document overview
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Technical content
Features
! Fully integrated, PLL-stabilized VCO ! Frequency range from 310 MHz to 440 MHz ! FSK through crystal pulling allows modulation from DC to 40 kbit/s ! High FSK deviation possible for wideband data transmission ! 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 equivalent radiated power (ERP) range from -25 dBm to -10 dBm ! Adjustable current consumption from 4.8 mA to 11.5 mA ! FSK deviation and center frequency independently adjustable ! Differential output well-suited for loop antenna ! External clock available for µC drive, down to 1.9 V supply ! ”Clock only” mode ! Conforms to EN 300 220 and similar standards
Ordering Information
Part No. EVB7107-433-FSK EVB7107-315-FSK EVB7107-433-ASK EVB7107-315-ASK Application Examples Evaluation Board Example ! Keyless car and central locking ! Low-power telemetry ! Alarm and security systems ! General digital data transmission ! General analog audio signal transmission General Description The TH7107 antenna board is designed to optimally match the differential power amplifier output to a loop antenna. The TH7107 can be populated either for FSK, ASK or FM transmission. The default population is for FSK or ASK transmission. Adding a varactor diode can easily be done in order to modify the circuit for analog FM. The evaluation board contains a differential-drive loop antenna printed on the PCB (Printed Circuit Board). The size of the loop antenna is matched to the resonant frequency.
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1 Theory of Operation
1.1 General
As depicted in Fig.1, the TH71071 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 P o can be adjusted in six steps from Po = –12 dBm to +2 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 kΩ . 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
Fig. 1: Block diagram with external components LF11 16 2LF2 SUB PA mode control VCOPFD div32 charge pump RF1 RPS CF2 CF1 VCC PS15 9 DATA CKOUT XOSC div 4 RO2 RO1 XTAL CX1 CX2 VCC 10 VEE OUT1 OUT2 VCC ENTX VEE ENCK antenna or balun
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2 Functional Description
2.1 FSK Modulation
A Colpitts crystal oscillator (XOSC) is used as the reference oscillator of a phase-locked loop (PLL) synthesizer. FSK modulation is achieved by pulling the crystal (XTAL) through the data. So a CMOS- compatible data stream applied at input DATA digitally modulates the XOSC. Two external pulling capacitors CX1 and CX2 allow the FSK deviation and center frequency to be adjusted independently. At DATA = LOW CX2 is connected in parallel to CX1 leading to the low-frequency component of the FSK spectrum (f min); while at DATA = HIGH CX2 is deactivated and the XOSC is set to its high frequency, leading to f max. An external reference signal can be directly AC-coupled to pin RO1. Then the TH7107 is used without an XTAL. The reference signal has to contain the FSK (or FM) and sets the carrier frequency.
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 ASK Modulation
The TH7107 can be ASK-modulated by applying data directly at pin PS. This turns the PA on and off and therefore leads to an ASK signal at the output.
2.4 Mode Control Logic
The mode control logic allows four different modes of operation as listed in the following table. The mode control pins ENCK and ENTX are pulled-down internally. This guarantees that the whole circuit is shut down if these pins are left floating. The clock output CKOUT can be used to drive a µC. This output can be activated by the ENCK pin as required for any specific application. Clock frequency is 1/4 of the reference crystal frequency. ENCK ENTX Mode Description 0 0 all OFF whole circuit in standby 0 1 TX only TX active, no clock available 1 0 clock only TX standby and clock available 1 1 all ON TX active and clock available For more detailed information, please refer to the latest TH7107 data sheet revision.
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3 Circuit Diagram
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3.1 PCB Top View
Board layout data in Gerber format is available Board size is 48mm x 48mm
3.2 Board Connection
VCC Power supply (2.2 V to 5.5 V) ENCK Mode control pin (see para. 2.4)) FSK Input for FSK data (CMOS) ENTX Mode control pin (see para. 2.4)) FM/ASK Input for FM signal (analog) or ASK data (CMOS) GND Several ground pins CKOUT Clock output (3.4 MHz) Melexis VCC ENCK
433 MHZ
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3.3 Board Component Values
315 MHz
433.6 MHz Tolerance Description
CF1 0805 12 nF 10 nF ±10% loop filter capacitor CF2 0805 15 pF 12 pF ±10% loop filter capacitor CX1_FSK 0603 39 pF 39 pF ±5% XOSC capacitor for FSK ( ∆f = ±20 kHz) CX1_ASK 0603 68 pF 68 pF ±5% XOSC capacitor for ASK, trimmed to fC CX2 0603 1 nF 1 nF ±5% XOSC capacitor, only needed for FSK CX3 0603 1 nF 1 nF ±10% XOSC capacitor, only needed for FM C1 1206 3.9 pF 3.9 pF ±2% antenna resonance capacitor C2 0805 3.9 pF 2.2 pF ±2% antenna resonance capacitor C3 0603 330 pF 330 pF ±10% blocking capacitor C4 0603 330 pF 330 pF ±10% blocking capacitor C5 1206 220 nF 220 nF ±20% blocking capacitor L1 0603 220 nH 220 nH ±10% biasing inductor L2 0603 220 nH 220 nH ±10% biasing inductor RF1 0805 2.0 kΩ 2.0 k Ω ±10% loop filter resistor RF2 0805 4.3 kΩ 4.3 k Ω ±10% loop filter resistor RPS 0805 56 kΩ 56 k Ω ±10% power-select resistor, see data sheet para. 4.6 R1 0805 470 kΩ 470 k Ω ±10% optional pull-up resistor, typically not needed R2 0805 30 kΩ 30 k Ω ±10% varactor bias resistor, only needed for FM R3 0805 0 Ω 0 Ω ±10% ASK jumper, only needed for ASK RX 0603 4.7 kΩ 4.7 k Ω ±10% damping resistor V1 SOD323 BB535 varactor diode, only needed for FM XTAL HC49/S
9.8438 MHz
13.5500 MHz
±30ppm calibration ±30ppm temp. crystal, Cload = 12 pF to 15 pF, C0, max = 7 pF Rm, max = 40 Ω PCB loop antenna long side length 44 mm 44 mm on FR4 PCB material side length including length of C1 and C2 PCB loop antenna small side length 20 mm 12 mm on FR4 PCB material PCB loop antenna Line width 2 mm 2 mm on FR4 PCB material The listed component values are default values. All values might be changed to fit to any specific application. As for example FSK deviation can be set by varying CX1 and CX2, output power at FSK/FM transmission can be changed through RPS or through RPS and R3 at ASK transmission, respectively. Pads for C1 are for population of a fixed-value capacitor with size 1206 or a to use trimming capacitor either.
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4 Package Information
Fig. 2: QSOP16 (Quarter size Small Outline Package) all Dimension in mm, coplanarity < 0.1mm D E1 E A A1 A2 e b ZD C L αααα all Dimension in inch, coplanarity < 0.004” 7° 3°+ L 0.254 (0.010)DETAIL-A 0.36 x 45° (0.0014x45°)BSC DETAIL-A C E b ZDe D A .10 (.004)
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5 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 life- support 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. © 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: All other locations: Phone: +32 1367 0495 Phone: +1 603 223 2362 E-mail: sales_europe@melexis.com E-mail: sales_usa@melexis.com QS9000, VDA6.1 and ISO14001 Certified