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overview the LA75691 is a pal/ntsc multichannel audio vif/sif signal-processing ic that makes the minimum number of adjustments possible. the system is designed so that vco adjustment makes aft adjustment unnecessary, thus simplifying the adjustment steps in end- product manufacturing. pll detection is adopted in the fm detector, allowing the LA75691 to support multichannel detection for the audio signal. in addition, it also incorporates a buzz canceller that suppresses nyquist buzz for improved audio quality. functions [vif block] pll detector with minimum number of adjustments aft equalizer amplifier rf agc [first sif block] first sif detector hpf [sif block] pll-based fm detector [muting block] av muting features excellent buzz and buzz/beating characteristics provided by a pll detection technique that includes a buzz canceller. the second if agc filter is built in. no coils are used in the aft and sif circuits, making them adjustment free. package dimensions unit: mm 3067-dip24s monolithic linear ic 90898rm (ot) no. 5734-1/13 sanyo: dip24s [LA75691] sanyo electric co.,ltd. semiconductor bussiness headquarters tokyo office tokyo bldg., 1-10, 1 chome, ueno, taito-ku, tokyo, 110-8534 japan if signal-processing ic for pal/ntsc multichannel audio tv and vcr systems LA75691 ordering number : en5734 ambient temperature, ta ?? allowable power dissipation, pd max ?w any and all sanyo products described or contained herein do not have specifications that can handle applications that require extremely high levels of reliability, such as life-support systems, aircraft? control systems, or other applications whose failure can be reasonably expected to result in serious physical and/or material damage. consult with your sanyo representative nearest you before using any sanyo products described or contained herein in such applications. sanyo 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 sanyo products described or contained herein.
no. 5734- 2 /13 LA75691 parameter symbol conditions ratings unit maximum supply voltage v cc max 13.2 v circuit voltage v13, v17 v cc v i6 ? ma circuit current i10 ?0 ma i24 ? ma allowable power dissipation pd max ta 68 c 720 mw operating temperature topr ?0 to +70 c storage temperature tstg ?5 to +150 c note: when mounted on a 65 72 1.6 mm laminated paper phenolic resin printed circuit board. specifications maximum ratings at ta = 25 c parameter symbol conditions ratings unit min typ max [vif block] circuit current i 5 35.5 42.0 48.5 v maximum rf agc voltage v 14h 7.5 8.1 v minimum rf agc voltage v 14l 0 0.5 v input sensitivity v in s1 = off 24 30 36 db v agc range g r 62 68 db maximum allowable input v in max 92 97 db v no-signal video output voltage v 6 3.5 3.8 4.2 v synchronizing signal tip voltage v 6 tip 1.15 1.45 1.74 v video output level v o 1.7 2.0 2.3 vp-p black noise threshold voltage v bth 0.5 0.8 1.1 v black noise clamp voltage v bcl 2.5 2.8 3.1 v video signal-to-noise ratio s/n 48 50 db c-s beating ic-s 38 43 db frequency characteristics f c 6 mhz ?.0 ?.5 db differential gain dg 3.0 6.5 % differential phase dp 3 5 deg maximum aft voltage v 13h 8.5 8.7 9.0 v minimum aft voltage v 13l 0 0.18 0.5 v aft detection sensitivity sf 22.4 28.0 33.6 mv/khz vif input resistance ri 38.9 mhz 1.5 k vif input capacitance ci 38.9 mhz 3 pf apc pull-in range (u) f pu 0.8 1.3 mhz apc pull-in range (l) f pl ?.5 ?.8 mhz aft frequency tolerances 1 dfa 1 ?00 0 +300 khz vco1 maximum variability range (u) dfu 1.0 1.3 mhz vco1 maximum variability range (l) dfl ?.5 ?.0 mhz vco control sensitivity b 1.4 2.8 5.6 khz/mv 5.5 mhz output level s o p/s = 14 db 92 95 98 mvrms [sif block] limiting voltage vi (lim) 5.5 mhz 30 khz 43 48 53 db v fm detector output voltage v o (fm) 5.5 mhz 30 khz 720 900 1100 mvrms am rejection ratio amr am = 30 % 50 60 db total harmonic distortion thd 0.3 0.8 % sif signal-to-noise ratio s/n (fm) 57 62 db operating characteristics at ta = 25 c, v cc = 9 v, f p = 38.9 mhz parameter symbol conditions ratings unit recommended supply voltage v cc 9 v operating supply voltage range v cc op 8.5 to 12.5 v operating conditions
pin assignment no. 5734- 3 /13 LA75691 internal equivalent circuit and external circuits
no. 5734- 4 /13 LA75691 ac characteristics test circuit test circuit impedance analyzer
no. 5734- 5 /13 LA75691 nt (us) inter
sample application circuit if the sif, aft, and rf agc circuits are not used: if the sif circuit is not used: pins 1, 23, and 24 should be left open. insert a 2-k resistor between pin 2 and ground. if the aft circuit is not used: since there is no way to defeat the aft circuit, connect a 100-k resistor and a 0.01- f capacitor in parallel between pin 13 and ground. if the rf agc circuit is not used: pins 14 and 21 should be left open. insert a 0.01- f capacitor between pin 21 and ground to prevent oscillation. no. 5734- 6 /13 LA75691
no. 5734- 7 /13 LA75691 pin descriptions pin no. pin function equivalent circuit sif input the input impedance is about 1 k . the pattern layout for the input circuit for this pin must be designed carefully, since buzzing and/or beating can be caused by interference signals. video signals, the chrominance signal, and the vif carrier signal can cause interference in the audio signal. 1 sif input the fm detector signal-to-noise ratio can be improved by inserting a filter in the fm detector bias line. c1 must be at least 0.47 f, and 1 f is recommended. if the fm detector is not used, insert a 2-k resistor between pin 2 and ground. this stops the fm detector vco. 2 fm power supply filter pin 3 is the first sif output. this is the output pin for the audio carrier to which p/s separate detection has been applied. this is an emitter- follower output with a 200 series resistor inserted. 3 first sif output continued on next page.
no. 5734- 8 /13 LA75691 continued from preceding page. pin no. pin function equivalent circuit the v cc to ground decoupling capacitors must be placed as close to the ic as possible. 5 v cc equalizer circuit. this circuit corrects the frequency characteristics of the video signal. pin 17 is the equalizer amplifier input. a 1.5-v p-p signal is input to pin 17, and that signal is amplified to be a 2-v p-p signal by the equalizer amplifier. equalizer amplifier design: the equalizer amplifier is designed as a voltage-follower amplifier with a gain of about 2.3 db. connect an inductor, a capacitor, and a resistor in series between pin 7 and ground if the frequency characteristics require correction. notes on the equalizer amplifier: if the input signal is vi and the output signal is vo, then: r1 +1 (vi + vin) = vo g z g: the voltage-follower amplifier gain. vin: imaginary short g: about 2.3 db assuming that vin is 0, then: vog r1 av = = +1 vi z r1 is the ic internal resistance of 1 k . simply select z to match the desired characteristics. however, note that z must be chosen carefully in order not to cause distortion, since the equalizer amplifier gain will be maximum at the resonance determined by z. 6 7 8 eq amp pll detector apc filter the apc time constant is switched internally in the ic. when locked, the vco is controlled by loop a, and the gain is reduced. when unlocked and in weak field reception, the vco is controlled by loop b, and the gain is increased. for this apc filter the recommended values are: r should be between 150 and 390 . c should be 0.47 f. 9 apc filter continued on next page.
no. 5734- 9 /13 LA75691 continued from preceding page. pin no. pin function equivalent circuit output for the video signal that includes the sif carrier a resistor must be inserted between pin 10 and ground to assure adequate drive capabilities. r 3 300 10 conposite video output connections for the vco tank circuit used by the video detector. see the coil specifications for the tank circuit provided separately. this vco is a vector synthesis vco. 11 12 vco tank aft output the aft center voltage is created by an external bleeder resistor. the aft gain increases as the value of this bleeder resistor increases. this resistor must not exceed 390 k . this circuit includes a function that controls the aft voltage to naturally approach the center voltage during weak field reception. 13 aft output rf agc output this signal controls the tuner rf agc. this is an emitter output with a 200 protective resistor inserted in series. determine the value of the external bleeder resistor according to the specifications of the tuner. 14 rf agc output 15 nc 16 nc continued on next page.
no. 5734- 10 /13 LA75691 continued from preceding page. pin no. pin function equivalent circuit if agc filter connection the agc voltage is created at pin 17 from the peak detection output produced by the internal agc detector. a second agc filter (a lag-lead filter) is built in the ic to create a dual time constant. use a 0.022- f capacitor as the external capacitor. adjust the value of the capacitor to compensate for sag, or modify the agc speed as required. 17 if agc filter vif amplifier input the input circuit is a balanced input and the input impedance corresponds to: r ? 1.5 k and c ? 3 pf. 18 19 vif input rf agc trimmer connection this pin is used to set the tuner rf agc operating point. the fm and video outputs can be muted at the same time by shorting this pin to ground. 20 gnd 22 nc 21 rf agc vr continued on next page.
no. 5734- 11 /13 LA75691 pin no. pin function equivalent circuit this filter is used to hold the fm detector output dc voltage fixed. normally, a 1- f electrolytic capacitor should be used. the value of this capacitor can be increased to improve the low band (around 50 hz) frequency characteristics. 23 fm filter audio fm detector output this is an emitter follower output with a 200- resistor inserted in series. ?stereo applications some applications may find that the stereo decoder input has a low input impedance, and that the left and right signals are distorted, i.e. that the stereo characteristics are degraded. if that is a problem, add the resistor r1 shown in the figure between pin 24 and ground. r1 3 5.1 k ?mono applications use an external deemphasis circuit with the following time constant: t = 2rc 24 fm detector output continued from preceding page.
notes on sanyo saw filters there are two types of saw filter that differ in the piezoelectric substrate material used. lithium-tantalum (litao3) saw filters tsf11 n n n n ... japan tsf12 n n n n ... us although lithium tantalate saw filters have the low temperature coefficient of -18 ppm/ c, they suffer from a large insertion loss. however, it is possible, at the cost of increasing the number of external components required, to minimize this insertion loss by using a matching circuit consisting of coils and other components at the saw filter output. at the same time as minimizing insertion loss, this technique also allows the frequency characteristics, level, and other aspects to be varied, and thus provides increased circuit design flexibility. also, since the saw filter reflected wave level is minimal, the circuit can be designed with a small in-band ripple level. lithium niobate (linbo3) saw filter tsf52 n n n n ... us tsf53 n n n n ... pal although lithium niobate saw filters have the high temperature coefficient of -72 ppm/ c, they feature an insertion loss about 10 db lower than that of lithium tantalate saw filters. accordingly, there is no need for a matching circuit at the saw filter output. although the in-band ripple is somewhat larger than with lithium tantalate saw filters, since they have a low impedance and a small field slew, they are relatively immune to influences from peripheral circuit components and the geometry of the printed circuit board pattern. this allows stable out-of-band trap characteristics to be acquired. due to the above considerations, lithium tantalate saw filters are used in applications for the us and japan that have a high if frequency, and lithium niobate saw filters are used in pal and us applications that have a low if frequency. notes on saw filter matching in saw filter input circuit matching, rather than matching the if frequency, flatter video band characteristics can be acquired by designing the tuning point to be in the vicinity of the audio carrier rather than the chrominance carrier. the situation shown in figure on the right makes it easier to acquire flat band characteristics than that in figure on the left. no. 5734- 12 /13 LA75691 when tuned to the if frequency when tuned near s or c the high-band frequency response is reduced saw filter characteristics the high-band frequency response is extended frequency frequency
ps no. 5734- 13 /13 LA75691 notes on vco tank circuits built-in capacitor vco tank circuits when power is applied to the ic, the heat generated by the ic is transmitted through the printed circuit board to the vco tank circuit. at this point, the vco coil frame functions as a heat sink and the ic heat is dissipated. as a result, this heat is not transmitted readily to the vco tank circuit's built-in capacitor, and drift at power on is reduced. therefore, it suffices to design the circuit so that the coil and capacitor thermal characteristics cancel. ideally, it is better to use a coil with a core material that has low temperature coefficient characteristics. external capacitor vco tank circuits when an external capacitor is used, heat generated by the ic is transmitted through the printed circuit board directly to the vco tank circuit external capacitor. while this capacitor is heated relatively early after the power is turned on, the coil is not influenced as much by this heat, and as a result the power-on drift is larger. accordingly, a coil whose core material has low temperature coefficient characteristics must be used. it is also desirable to use a capacitor with similarly low temperature coefficient characteristics. note: applications that use an external capacitor here must use a chip capacitor. if an ordinary capacitor is used, problems such as the oscillator frequency changing with the capacitor orientation may occur. this catalog provides information as of june, 1998. specifications and information herein are subject to change without notice. specifications of any and all sanyo products described or contained herein stipulate the performance, characteristics, and functions of the described products in the independent state, and are not guarantees of the performance, characteristics, and functions of the described products as mounted in the customer? products or equipment. to verify symptoms and states that cannot be evaluated in an independent device, the customer should always evaluate and test devices mounted in the customer? products or equipment. sanyo electric co., ltd. strives to supply high-quality high-reliability products. however, any and all semiconductor products fail with some probability. it is possible that these probabilistic failures could give rise to accidents or events that could endanger human lives, that could give rise to smoke or fire, or that could cause damage to other property. when designing equipment, adopt safety measures so that these kinds of accidents or events cannot occur. such measures include but are not limited to protective circuits and error prevention circuits for safe design, redundant design, and structural design. in the event that any or all sanyo products (including technical data, services) described or contained herein are controlled under any of applicable local export control laws and regulations, such products must not be exported without obtaining the export license from the authorities concerned in accordance with the above law. no part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying and recording, or any information storage or retrieval system, or otherwise, without the prior written permission of sanyo electric co., ltd. any and all information described or contained herein are subject to change without notice due to product/technology improvement, etc. when designing equipment, refer to the ?elivery specification for the sanyo product that you intend to use. information (including circuit diagrams and circuit parameters) herein is for example only; it is not guaranteed for volume production. sanyo believes information herein is accurate and reliable, but no guarantees are made or implied regarding its use or any infringements of intellectual property rights or other rights of third parties. coil specifications japan us pal f = 58.75 mhz f = 45.75 mhz f = 38.9 mhz vco coils test production no. 16991b test production no. 16687b test production no. 16686b tokyo parts industrial co., ltd. tokyo parts industrial co., ltd. tokyo parts industrial co., ltd. saw filters (split) picture picture picture tsf1137u tsf1241 tsf5315 sound sound sound saw filters (inter) tsf5220 tsf5321 tsf5221 tsf5344

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