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unisonic technologies co., ltd L2572 linear integrated circuit www.unisonic.com.tw 1 of 14 copyright ? 2007 unisonic technologies co., ltd qw-r102-032.a wideband pll fm demodulator ? description as a wideband pll fm demodulator, the utc L2572 is intended for application in satellite tuners primarily. the device includes all the necessary elements, with external oscillator sustaining network and the exception of loop feedback components, to form a pll system operating at frequencies up to 800mhz completely. an afc with window adjust (whose output signal can be used to correct for any frequency drift at the head end local oscillator) is provided. ? features * constant voltage and constant current control * single chip pll system for wideband fm demodulation * simple low component count application * allows for application of threshold extension * fully balanced low radiation design * high operating input sensivity * improved vco stability with variations in supply or temperature * agc detect and bias adjust * 75 ? video output drive with low distortion levels * dynamic self biasing analog afc * full esd protection sop-16 *pb-free plating product number: L2572l ? ordering information ordering number normal lead free plating package packing L2572-s16-r L2572l-s16-r sop-16 tape reel L2572-s16-t L2572l-s16-t sop-16 tube
L2572 linear integrated circuit unisonic technologies co., ltd 2 of 14 www.unisonic.com.tw qw-r102-032.a ? pin configuration ? pin description pin no. pin name i/o description 1 afc pump i current pump, integrati ng the signal pulses into a dc voltage 2 afc window adjust i set the afc deadband voltages corresponding the frequency 3 v ee gnd 4 oscillator+ i oscillator positive signal 5 oscillator- i oscillator negative signal 6 agc bias i set the agc bias 7 agc output o output agc dc voltage 8 rf input i input signal 9 rf input i input signal 10 video output o output video signal 11 video feedback- i feedback the video negative signal 12 video+ o video positive signal 13 video- o video negative signal 14 video feedback+ i feedback the video positive signal 15 v cc input v cc 16 afc output o output afc dc voltage
L2572 linear integrated circuit unisonic technologies co., ltd 3 of 14 www.unisonic.com.tw qw-r102-032.a ? block diagram
L2572 linear integrated circuit unisonic technologies co., ltd 4 of 14 www.unisonic.com.tw qw-r102-032.a test configuration base band video 1v p &? p video generator rohde & schwarz sgpf tv sat test tx rohde & schwarz sfz rf carrier freq 479.5mhz fm modulation 13.5mhz p &? p pre &? emphasised video test application board see fig. 1 for details montford test oven pre emphasised base band video video amplifier/ de emphasised network video analyser rohde & schwarz uaf de emphasised base band video 1v p &? p using the above test configuration t he video drive characteristics measurem ents were made. in the electrical characteristics table the maximum figures recorded coinci de with extremes of supply voltage and high temperatures. there?s no adjustment to the recorded figures has been made to compensate for the effe cts of temperature on the external components of the application te st board, in the varactor diodes par ticularly. attention to temperature compensation of the external circuitry will result in perfo rmance figures closer to the stated typical figures if operation of the device at high ambient temperatures is envisaged.
L2572 linear integrated circuit unisonic technologies co., ltd 5 of 14 www.unisonic.com.tw qw-r102-032.a ? absolute maximum ratings (v ee 0v) parameter symbol ratings unit supply voltage v cc -0.3~7 v rf input voltage v in(rf) 2.5 v p-p rf input dc offset v in_rf(off) -0.3~v cc +0.3 v oscillator dc offset v osc(off) -0.3~v cc +0.3 v video dc offset -0.3~v cc +0.3 v video feedback dc offset -0.3~v cc +0.3 v video output dc offset v vdo(off) -0.3~v cc +0.3 v afc pump dc offset -0.3~v cc +0.3 v afc disable dc offset -0.3~v cc +0.3 v afc deadband dc offset v afc(off) -0.3~v cc +0.3 v agc bias dc offset -0.3~v cc +0.3 v agc output dc offset v agc(off) -0.3~v cc +0.3 v power dissipation (at 5.5v) p d 250 mw esd protection - pin 1 to 15 2 kv esd protection - pin 16 esd 1.7 kv junction temperature t j 150 c storage temperature t stg -55~125 c note: absolute maximum ratings are those values beyond which the device could be permanently damaged. absolute maximum ratings are stress ratings only and functional device oper ation is not implied. ? thermal data parameter symbol ratings unit junction to ambient ja 111 c/w junction to case jc 41 c/w ? electrical characteristics (ta = -20c~+80c, v cc = +4.5v ~ +5.5v. either design or production test guarantee the electr ical characteristics. unless otherwise stated they apply within the spec ified ambient temperature and supply voltage.) parameter symbol conditions min typ max unit supply current v cc 36 40 ma operating frequency f opr 300 800 mhz input sensitivity pream p limiting -40 dbm input overload 0 dbm vco sensitivity (df/dv) refer to fig. 1 25 32 39 mhz/v vco linearity refer to fig. 1 with13.5mhz p-p deviation 25 % vco supply stability see note 5 2.0 mhz/v vco temperature stability see note 5 20 khz/c phase detector gain differential loop filter single ended loop filter 0.5 0.25 v/rad loop amplifier input impedance r in 450 570 700 ? loop amplifier output impedance r out(loop) 25 ? loop amplifier open loop gain 38 db loop amplifier gain bandwidth product b w 240 mhz loop amplifier output swing 1.2 vp-p video drive output impedance r out(video) 55 75 95 ?
L2572 linear integrated circuit unisonic technologies co., ltd 6 of 14 www.unisonic.com.tw qw-r102-032.a ? electrical characteristics(cont.) parameter symbol conditions min typ max unit video drive luminance nonlinearity differential gain differential phase intermodulation signal/noise tilt baseline distortion 1k ? load, see note 3 and 4 75k ? load, see note 3 and 4 75k ? load, see note 3 and 4 see notes 1, 3 and 4 1k ? load, see note 2 and 4 1k ? load, see note 3 and 4 1k ? load, see note 3 and 4 66 1.9 0.5 1.0 72 0.3 0.4 5 2.5 3 -40 3 2 % % degree db db % % agc output current i out maximum load voltage drop 2v 10 400 a agc bias current i bias 0 250 a afc window current 400a gives 1.5v deadband window 0 400 a afc charge pump current 50 a afc leakage current i leak with charge pump disabled 10 a afc output saturation voltage v o(sat) afc output enabled 0.4 v note 1. input modulation?s product f 1 at 4.43mhz, 13.5mhz p?p deviation a nd f 2 at 6mhz p?p deviation, (pal chroma and sound subcarriers). 2. to output rms noise in 6mhz bandwidth with no inpu t modulation, ratio of output video signal with input modulation at 1mhz, 13.5mhz p?p deviation. 3. output voltage is 600mv pk?pk and input test signal pre?emphasised video 13.5mhz p?p deviation. 4. see page 4 5. assuming ambient temperature of +20c and operating frequency of 479.5mhz set with v cc @ 5.0v. only applies to application shown in fig. 1 also refer to fig. 4.
L2572 linear integrated circuit unisonic technologies co., ltd 7 of 14 www.unisonic.com.tw qw-r102-032.a ? application circuit
L2572 linear integrated circuit unisonic technologies co., ltd 8 of 14 www.unisonic.com.tw qw-r102-032.a ? functional description the utc L2572 as optimized for application in satellite receiver systems and requiring a minimum external component count is a wideband pll fm demodulator. it includes all the elements required to construct a phase locked loop circuit, with the exception of an afc detector ci rcuit for generation of error signal to correct for any frequency drift in the outdoor unit local oscillator, and tu ning components for the local oscillator contains a block diagram and fig. 1 contains the typical application. fig. 2-1 contains the internal pin connections in applications the second satellite if fr equency of typically 479.5 or 402mhz is fed to the rf preamplifier normally, which depending on application and layout has a working sensitivity of typically -40 dbm. an rf level detect circuit, which generates an agc signal that can be used for controlling the gain of the if amplifie r stages is contained in the preamplifier, so it can be maintaining a fixed level to the rf input of the utc L2572, for optimum threshold performance. the agc circuit?s bias point can be adjusted to cater for device input power and variation in agc line voltage requirement. fig. 5 shows the typical agc curves are shown in. that the device is recommended that be operated with an input signal between -30 and -35dbm. that can ensure optimum linearity and threshold performance, and when over the typical sensitivity of -40dbm can give a good safety margin. the preamplifier?s output is fed to the mixer section which is of balanced desig n for low radiation. in this stage the rf signal is mixed with which is generated by an on?board oscillator, the local oscillat or frequency. the oscillator block is optimized for high linearity over the normal deviati on range and uses an external varactor tuned sustaining network. fig. 3 contains a typical frequ ency versus voltage characteristic for the oscillator. fig.4 shows the typical stability that he loop output is des igned to compensate for first order temperature variation effects. the mixer?s output is then fed to the loop amplifier around which feedba ck is applied to effect loop transfer characteristic. feedback could be applied either in single ended or differential mode; both modes should give the same loop response if the appropriate phase detecto r gains are assumed in ca lculating loop filters. the loop amplifier drives a 75 ? output impedance buffer amplifier, which could be connected to a 75 ? load and used to drive a high input impedance stage giving greater linearity and approximately 6db higher demodulated signal output level too.
L2572 linear integrated circuit unisonic technologies co., ltd 9 of 14 www.unisonic.com.tw qw-r102-032.a ? internal circuits v cc agc output v ref:2.7v fig. 2-1 agc output v ref:2v fig. 2-2 agc bias adjust agc bias v ref:1.6v fig. 2-4 afc window adjust afc window rf input v ref:36v 2x1500 fig. 2-3 rf input afc output afc pump v cc 10k fig. 2-5 afc output stage fig. 2-6 video amp output 2ma 2ma 330 330 video - video +
L2572 linear integrated circuit unisonic technologies co., ltd 10 of 14 www.unisonic.com.tw qw-r102-032.a ? internal circuits(cont.) v ref:1.2v 2x5k oscillator + oscillator - fig. 2-7 local oscillator 2x570 from phase detector video feedback + video feedback - fig. 2-8 video amp feedback inputs 4ma 105 68 fig. 2-9 video output drive output video v cc
L2572 linear integrated circuit unisonic technologies co., ltd 11 of 14 www.unisonic.com.tw qw-r102-032.a frequency (mhz) frequency (mhz) -70 -60 -50 -40 -30 0.5 1.0 1.5 2.0 agc voltage output (v) rf input level (dbm) unmodulated -20 -10 0 agc bias resistor 5.1k agc bias current 297 a agc load resistor 3.9k v cc = 5.0 v fig.5 agc output voltage for differing values of agc bias resistor agc bias resistor 10.5k agc bias current 150 a agc load resistor 4.7k agc bias resistor 32k agc bias current 52 a agc load resistor 10k
L2572 linear integrated circuit unisonic technologies co., ltd 12 of 14 www.unisonic.com.tw qw-r102-032.a ? design of pll loop parameters the utc L2572 is normally used as a type 1 second orde r loop and can be represented by the above diagram. for such a system the following parameters apply; 7 1 = c1.r1 7 2 = c1.r2 and 2 0 1 n d k k = n 2 2 = where: k 0 is the vco gain in radian seconds per volt k d is the phase detector gain in volts per radian n is the natural loop bandwidth is the loop damping factor r1 is loop amplifier input impedance note: k 0 is dependant on sensitivity of vco used. k d = 0.25v/rad single ended, 0.5v/rad differential from these factors the loop 3db bandwidth c an be determined from the following expression; 1 ) 1 2 ( ) 1 2 ( 2 2 2 2 2 2 3 + + + = n n db which approximates to n db 2 3 = when 2 1 =
L2572 linear integrated circuit unisonic technologies co., ltd 13 of 14 www.unisonic.com.tw qw-r102-032.a ? afc facility an analog frequency error detect circuit, which generates dc voltage proportional to the integral of frequency error is contained in utc L2572.as the inci dent rf is high then the afc voltage in creases, as low then the voltage decreases. adc converts the afc voltage can then be an to be read by the micro controller for frequency fine tuning. around the aligned frequency the afc detect circuit contains a deadband centre. from zero window to approximately 25mhz width assuming an oscillator df/dv of 15mhz/v t he deadband can be adjusted. the afc voltage does not integrate if the in cident rf is within this window, except by component leakage. with reference to fig. 6; the demodu lated video is fed to a dual comparat or which can be compared with two reference voltages in normal operation, corresponding to t he extremes of the deadband, or window. these voltages are variable and the window adjust input can set it. two digital outputs corresponding to voltages above or below the voltage window, or frequency above or below deadband can be produced by the comparators. these digita l control signals can control a complimentary current source pump. the current signals are then fed to an amplifier?s input. it is arr anged as an integrator , so integrating the pulses into a dc voltage. both the current source and sink are disabled if the frequency is correctly a ligned, therefore t he dc output voltage can be constant. due to component leak age there will be a small drift; the maximum drift can be calculated from here: c i dt dv . 2500 = where ext r vcc i = , c = c ext
L2572 linear integrated circuit unisonic technologies co., ltd 14 of 14 www.unisonic.com.tw qw-r102-032.a utc assumes no responsibility for equipment failures that result from using products at values that exceed, even momentarily, rated values (such as maximum ratings, operating condition ranges, or other parameters) listed in products specifications of any and all utc products described or contained herein. utc products are not designed for use in life support appliances, devices or systems where malfunction of these products can be reasonably expected to result in personal injury. reproduction in whole or in part is prohibited without the prior writ ten consent of the copyright owner. the information presented in this document does not form part of any quotation or contract, is believed to be accurate and reliable and may be changed without notice.

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