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71509 sy pc/32301tn (ot) no.6038-1/48 specifications of any and all sanyo semiconductor co.,l td. 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 ' s 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 ' sproductsor equipment. any and all sanyo semiconductor co.,ltd. products described or contained herein are, with regard to "standard application", intended for the use as general el ectronics equipment (home appliances, av equipment, communication device, office equipment, industrial equ ipment etc.). the products mentioned herein shall not be intended for use for any "special application" (medica l equipment whose purpose is to sustain life, aerospace instrument, nuclear control device, burning appliances, t ransportation machine, traffic signal system, safety equipment etc.) that shall require extremely high level of re liability and can directly threaten human lives in case of failure or malfunction of the product or may cause har m to human bodies, nor shall they grant any guarantee thereof. if you should intend to use our products for app lications outside the standard applications of our customer who is considering such use and/or outside the scope of our intended standard applications, please consult with us prior to the intended use. if there is n o consultation or inquiry before the intended use, our customer shall be solely responsible for the use. LA1781M overview the LA1781M integrates all six blocks required in a car radio tuner on a single chip. features ? improved noise reduction methods the fm front end provides excellent 3-signal characteristics equivalent to those of the la1193m. superlative listenability due to improved medium and weak field noise canceller characteristics. improved separation characteristics. anti-birdie filter. improved am and fm thermal characteristics. excellent fm signal meter linearity. modified n.c. circuit for improved noise rejection. ? double conversion am tuner (up conversion) reduces the number of external components required as comp ared to earlier double conversion tuners, in particular, no crystal is required (when used in conjunction with the lc72144). ? sample-to-sample variation reduction circuit built into the fm if circuit. (fixed resistors are used for the sd, keyed agc, mute on adjustment, att, snc, and hcc functions.) ? the la1781 inherits the block arrangement of the la1780m and supports pin-compatible designs. functions ? fm front end ? fm if ? noise canceller ? multiplex ? am up-conversion ? fm/am switch ? mrc monolithic linear ic for car radios single-chip tuner ic orderin g numbe r : en6038a
LA1781M no.6038-2/48 specifications maximum ratings at ta = 25 c parameter symbol conditions ratings unit v cc 1 max pins 6, 40, and 61 9 v maximum supply voltage v cc 2 max pins 7, 45, 54, 59, and 60 12 v allowable power dissipation pd max ta 55 c 950 mw operating temperature topr -40 to +85 c storage temperature tstg -40 to +150 c operating conditions at ta = 25 c parameter symbol conditions ratings unit v cc pins 6, 7, 40, 45, 54, 59, 60, and 61 8 v recommended supply voltage v cc st ind pin 26 5v operating supply voltage range v cc op 7.5 to 9.0 v electrical characteristics at ta = 25c, v cc = 8v, in the specified test circuit for the fm if input ratings parameter symbol conditions min typ max unit fm characteristics at the fm if input current drain i cco -fm no input, i40 + i45 + i54 + i59 + i60 + i61 60 94 110 ma demodulation output v o -fm 10.7mhz, 100db , 1khz, 100%mod, the pin 15 output 205 310 415 mvrms pin 31 demodulation output v o -fm31 10.7mhz, 100db , 1khz, 100%mod, the pin 31 output 190 295 380 mvrms channel balance cb the ratio between pins 15 and 16 at 10.7mhz, 100db , 1khz -1 0 +1 db total harmonic distortion thd-fm mono 10.7mhz, 100db , 1khz, 100% mod, pin 15 0.3 1.0 % signal-to-noise ratio : if s/n-fm if 10.7mhz, 100db , 1khz, 100% mod, pin 15 75 82 db am suppression ratio: if amr if 10.7mhz, 100db , 1khz, fm = 1khz, 30% am, pin 15 55 68 db att-1 10.7mhz, 100 db , 1khz. the pin 15 attenuation when v33 goes from 0 to 2v 5 10 15 db att-2 10.7mhz, 100 db , 1khz. the pin 15 attenuation when v33 goes from 0 to 2v* 1 15 20 25 db muting attenuation att-3 10.7mhz, 100 db , 1khz. the pin 15 attenuation when v33 goes from 0 to 2v* 2 28 33 38 db separation sep 10.7mhz, 100db , l + r = 90%, pilot = 10%. the pin 15 output ratio 30 40 db stereo on level st-on the pilo t modulation such that v26 < 0.5v 2.1 4.1 6.5 % stereo off level st-off the pilo t modulation such that v26 > 3.5v 1.2 3.1 % main total harmonic distortion thd-main l 10.7mhz, 100db , l + r = 90%, pilot = 10%. the pin 15 signal 0.3 1.2 % pilot cancellation pcan 10.7mhz, 100db , pilot = 10%. the pin 15 signal/the pilot level leakage. din audio 20 30 db snc output attenuati on attsnc 10.7mhz, 100db , l - r = 90%, pilot = 10%. v28 = 3v 0.6v, pin 15 1 5 9 db atthcc-1 10.7mhz, 100db , 10khz, l + r = 90%, pilot = 10%. v29 = 3v 0.6v, pin 15 0.5 4.5 8.5 db hcc output attenuation atthcc-2 10.7mhz, 100db , 10khz, l + r = 90%, pilot = 10%. v29 = 3v 0.1v, pin 15 6 10 14 db input limiting voltage v in -lim 100db , 10.7mhz, 30% modulation. t he if input such that the input reference output goes down by 3db 33 40 47 db muting sensitivity v in -mute the if input level (unmodulated) when v33 = 2v 27 35 43 db sd-sen1 fm the if input level (unmodulated) (over 100mv rms) such that the if counter buffer output goes on 54 62 70 db sd sensitivity sd-sen2 fm 54 62 70 db if counter buffer output v ifbuff-fm 10.7mhz, 100db , unmodulated. the pin 23 output 130 200 270 mvrms v sm fm-1 no input. the pin 24 dc output, unmodulated 0.0 0.1 0.3 v v sm fm-2 50db . the pin 24 dc output, unmodulated 0.4 1.0 1.5 v v sm fm-3 70db . the pin 24 dc output, unmodulated 2.0 2.7 3.5 v signal meter output v sm fm-4 100db . the pin 24 dc output, unmodulated 4.7 5.5 6.2 v muting bandwidth bw-mute 100db . the bandwidth when v33 = 2v, unmodulated 150 220 290 khz mute drive output v mute -100 100db , 0db . the pin 33 dc output, unm odulated 0.00 0.03 0.20 v continued on next page.
LA1781M no.6038-3/48 continued from preceding page. ratings parameter symbol conditions min typ max unit fm fe mixer input n-agc on input v nagc 83mhz, unmodulated. the input such that the pin 2 voltage is 2.0v or below 81 88 95 db w-agc on input v wagc 83mhz, unmodulated. the inpu t such that the pin 2 voltage is 2.0v or below. (when the keyed agc is set to 4.0v.) 104 110 116 db conversion gain a. v 83mhz, 80db , unmodulated. the fe cf output 19 30 48 mvrms oscillator buffer output v osc buff-fm no input 85 110 165 mvrms nc block nc input (pin 30) gate time t gate f = 1khz, for a 1 s, 100-mvp-o pulse 55 s noise sensitivity sn the level of a 1khz, 1 s pulse input that starts noise canceller operation. measured at pin 30. 40 mvp-o nc effect sn-nc the pulse rejection effe ct provided by the noise canceller. for a repeated 1 s wide pulse, frequency = 10khz, 150mvp-o. the ratio of the fm mode pin 15 output referenced to the am mode pin 15 output (effective value) 5 multipath rejection circuit mrc input (pin 27) mrc output v mrc v24 = 5v 2.2 2.3 2.4 v mrc operating level mrc-on the pin 32 i nput level at f = 70khz such that pin 24 goes to 5v and pin 27 goes to 2v 10 15 20 mvrms am characteristics am ant input practical sensitivity s/n-30 1mhz, 30db , fm = 1khz, 30% modulation, pin 15 20 db detector output v o -am 1mhz, 74db , fm = 1khz, 30% modulation, pin 15 130 195 270 mvrms pin 31 detector output v o -am31 1mhz, 74db , fm = 1khz, 30% modulation, pin 31 110 175 230 mvrms agc f.o.m. v agc-fom 1mhz, 74db , referenced to the output, the input amplitude such that the output falls by 10db. pin 15 59 64 69 db signal-to-noise ratio s/n-am 1mhz, 74db , fm = 1khz, 30% modulation 47 52 db total harmonic distortion thd-am 1mhz, 74db , fm = 1khz, 80% modulation 0.3 1 % v sm am-1 no input 0.0 0.2 0.5 v signal meter output v sm am-2 1mhz, 130db , unmodulated 3.5 4.4 6.1 v oscillator buffer output v osc buff-am1 no input, the pin 15 output 185 230 mvrms w-agcsen1 1.4mhz, the input when v46 = 0.7v 92 98 104 db wide band agc sensitivity w-agcsen2 1.4mhz, the input when v46 = 0.7v (seek mode) 83 89 95 db sd-sen1am 1mhz, the ant input level such that the if counter output turns on. 24 30 36 db sd sensitivity sd-sen2am 1mhz, the ant input level such that the sd pin goes to the on state. 24 30 36 db if buffer output v ifbuff -am 1mhz, 74db , unmodulated. the pin 23 output 200 290 mvrms note : these measurements must be made usin g the either the ic-51-0644-824 or ks8277 ic socket (manufactured by yamaichi electr onics). *1. when the resistor between pin 58 and ground is 200k . *2. when the resistor between pin 58 and ground is 30k .
LA1781M no.6038-4/48 package dimensions unit : mm (typ) 3159a function list 1. fm front end (equivalent to the sanyo la1193) 4. multiplex functions (1) double input type double balanced mixer (1) adjustment-free vco circuit (2) pin diode drive agc output (2) level follower type pilot canceller circuit (3) mosfet second gate drive agc output (3) hcc (high cut control) (4) keyed agc adjustment pin (4) automatic stereo/mono switching (5) differential if amplifie r (5) vco oscillation stop function (am mode) (6) wide band agc sensitivity setting pin, and narrow (6) forced monaural band agc sensitivity setting pin (7) snc (stereo noise controller) (7) local oscillator (8) stereo display pin (9) anti-birdie filter 2. fm if (1) if limiter amplifier 5. am (2) s-meter output (also used for am) 6-stage pickup (1) double balanced mixer (1st, 2nd) (3) multipath detection pin (shared fm signal meter) (2) if amplifier (4) quadrature detection (3) detection (5) af preamplifier (4) rf agc (narrow/wide) (6) agc output (5) pin diode drive pin (7) band muting (6) if agc (8) weak input muting (7) signal meter output (also used for fm) (9) soft muting adjustment pin (8) local oscillator circuits (first and second) (10) muting attenuation adjustment pin (9) local oscillator buffer output (11) if counter buffer output (also used for am) (10) if counter buffer output (also used by the fm if) (12) sd (if counter buffer on level) adjustment pin (11) sd (if counter buffer on level) adjustment pin (13) sd output (active high) (also used for am) (12) sd output (active high) (also used for am) (13) wide agc 3. noise canceller (14) det ection output frequency characteristics (1) high-pass filter (first order) adjustment pin (low cut, high deemphasis) (2) delay circuit based low-pass filter (fourt h order) (15) am stereo buffer (3) noise agc (4) pilot signal compensation circuit 6. mrc (multipath noise rejection circuit) (5) noise sensitivity setting pin (6) function for disabling the noise canceller in am 7. am/fm switching output (linked to the fm v cc ) mode sanyo : qip64e(14x14) 14.0 17.2 14.0 17.2 0.15 0.35 0.8 (2.7) 3.0max 0.1 0.8 (1.0) 116 17 32 33 48 49 64 pd max -- ta 0 400 300 600 500 800 900 950 700 200 100 1000 --40 --20 80 60 20 40 0 100 ambient temperature, ta -- c allowable power dissipation, pd max -- mw mounted on a specified board : 40 80 1.3mm 3 glass epoxy board independent ic
LA1781M no.6038-5/48 operating characteristics and symbols used in the test circuit diagrams (1) switches (sw) switch on = 1, sw off = 0 there are two switches that use signal transfer. 1) sw2 : switches between the mixer input and the if input. 2) sw4 : switches between noise canceler in put and if output + noise canceler input. (2) types of sg used pg1 (ac1) used for noise canceler testing. a pul se generator and an af oscillator are required. ac2 used for fm front end test ing. outputs an 83mhz signal. ac3 used for fm if, noise canceler, and mpx testing. out puts a 10.7mhz signal. stereo modulation must be possible. ac4 used for am testing. outp uts 1 mhz and 1.4mhz signals. ac5 used with the mrc. can also be used for af and osc. (3) power supply v cc 8v v cc 1 5v sd, stereo, seek/stop v cc 2 0.1v/0.7v/2v/4v keyed agc, mute att v cc 3 0.1v/0.6v/2v these levels must be variable. hcc, snc, sasc (mrc) (4) (a) switches parameter on off sw1 am/fm switching. the fe v cc is supplied to pin 62. fm am sw2 fm if switching. pin 51/fe output fe if out (a) ac3 (b) sw3 for conversion gain testing conversion gain measurement (a) other/purposes sw4 for switching between noise canceler input and if output + noise canceler. ac1 (a) other/purposes sw5 high-speed sd high-speed sd other/purposes sw6 seek/stop (if buff on/off) st op seek (if buffer output) sw7 mute att 200k mute 200k off sw8 mute att 30k mute 30k off sw9 for pilot cancellation testing when pilot cancel lation is used when pilot cancellation is not used sw10 mute off (pin 33) mute off mute on (b) trimmers (variable resistors) vr1 separation adjustment vr2 pilot cancellation adjustment (5) test points (a) dc voltages vd1 fm rf agc voltage pin 2 vd2 am/fm sd, am tweet, fm stereo indicator pin 26 vd3 am/fm s-meter pin 24 vd4 mrc output pin 27 vd5 mute drive output pin 33 vd6 am antenna damping voltage pin 46 vd7 n.c. gate time pin 8 (b) ac voltages va1 am/fm osc buff pin 4 va2 first if output pin 53 cf pin 51 load level (10.7mhz) va3 if counter buffer pi n 23 (10.7mhz/450khz) va4 mpx out left ch pin 15 (af) va5 mpx out right ch pin 16 (af)
LA1781M no.6038-6/48 pin descriptions pin no. pin function pin description equivalent circuit 1 antenna damping drive an antenna damping current flows when the rf agc voltage (pin 2) reaches v cc - v d . 1 a nt 1000pf 1000pf 100 100 300 v cc pin 62 rf agc 2 rf agc used to control the fet second gate. + 2 n agc det w agc det keyed agc ant damping driver v cc v cc 12k fet 2nd gate 3 f.e.gnd 4 osc oscillator connection. the transistor and capacitors required for the oscillator circuit are integrated on the chip. v t v cc 25pf 20pf 2k 4 7 am osc am first oscillator. this circuit can oscillator up to the sw band. an alc circuit is included. 7 v cc a l c continued on next page.
LA1781M no.6038-7/48 continued from preceding page. pin no. pin function pin description equivalent circuit 8 9 noise agc sensitivity agc adjustment after setting up the medium field (about 50db ) sensitivity with the noise sensitivity setting pin (pin 8), set the weak field (about 20 to 30db ) sensitivity with the agc adjustment pin (pin 9). + 8 9 3k 15k 3k 3k 1m 0.01 f 0.47 f 200 11 12 memory circuit connection recording circuit used during noise canceller operation. 13 12 11 v cc 3.9k 0.01 f 6800pf differential amp gate circuit lpf 13 pilot input pin 13 is the pll circuit input pin. 12 13 30k v cc pll n.c 0.01 f 14 n.c, mpx, mrc, gnd ground for the n.c., mpx, and mrc circuits. continued on next page.
LA1781M no.6038-8/48 continued from preceding page. pin no. pin function pin description equivalent circuit 15 16 mpx output (left) mpx output (right) deemphasis 50 s : 0.015 f 75 s : 0.022 f 15 3.3k 3.3k v cc 0.015 f 0.015 f 16 17 pilot canceller signal output adjustment is required since the pilot signal level varies with the sample-to-sample variations in the if output level and other parameters. 17 18 v cc 20k 10k 0.01 f 100k 6.7k 18 pilot canceller signal output pin 18 is the output pin for the pilot canceller signal. 17 18 v cc 0.01 f 1.5k 100k 19 separation adjustment pin use a trimmer to adjust the subdecoder input level. (the output level is not modified in mono and main modes.) 19 5k composit signal decoder 30k 0.047 f continued on next page.
LA1781M no.6038-9/48 continued from preceding page. pin no. pin function pin description equivalent circuit 20 vco the oscillator frequency is 912hz. kbr-912f108 (kyocera corporation) csb-912jf108 (murata mfg. co., ltd.) 20 csb 912 jf104 v ref 10pf 21 22 phase comp. phase comp. + + + 21 22 15k 15k 19k v ref 23 if counter buffer seek/stop switching this pin functions both as the if counter buffer (ac output) and as the seek/stop switch pin. the voltage v23 switches between the following three modes. during fm reception : 5v : seek mode 2.5v : forced sd mode 0v : reception mode am reception (two modes : 0 and 5v) 5v : seek mode 0v : reception mode 23 + -- + -- + -- 4.9v 50k 150 50f 1.3v 10k 51k stop if buff. forced sd:2.5v seek 5v sd circuit sw v cc am mute if counter buffer continued on next page.
LA1781M no.6038-10/48 continued from preceding page. pin no. pin function pin description equivalent circuit 24 32 am/fm signal meter dedicated fm signal meter fixed-current drive signal meter output. in am mode, pin 32 outputs a 1ma current. thus the hcc circuit is turned off. 32 24 10k 10k v cc fm s-meter am s-meter am/fm sw am/fm sw mrc outputs a 1-ma current during am reception 26 stereo indicator for the sd pin the voltage v23 switches between three modes as follows. fm reception : 5v : the sd pin operates linked to the if counter buffer. 2.5v : forced sd mode: operates as the sd pin. 0.7v : reception mode: stereo indicator am reception : (two modes : 0 and 5v) 5v : operates as the seek sd pin. 0v : reception mode. not used. 26 100k v dd am/fm sd stereo indicator seek/stop switching 27 mrc control voltage time constant the mrc detector time constant is determined by a 100 resistor and c2 when discharging and by the 2 a current and c2 when charging. + 27 2 a 100 c2 v cc v cc pin 28 28 snc control input the sub-output is controlled by a 0 to 1v input. 28 v ref continued on next page.
LA1781M no.6038-11/48 continued from preceding page. pin no. pin function pin description equivalent circuit 29 hcc control input the high band frequency output is controlled by a 0 to 1v input. it can also be controlled by the mrc output. use a resistor of at least 100k when controlling with the pin 32 fm s-meter signal. + 32 1 f 29 v ref 30 31 noise canceller input am/fm detector output pin 30 is the noise canceller input. the input impedance is 50k . pin 31 is the am and fm detector output in fm mode, this is a low-impedance output. in am mode, the output impedance is 10k . to improve the low band separation, use a coupling capacitor of over 10 f. 31 30 + am detector fm detector output v cc v cc 10k 1 f noise canceller 50k 4.2v 32 if s-meter output and mrc dc input fm s-meter output block mrc ac input block adjust the external 1k resistor to attenuate the mrc ac input and control the circuit. + 32 v cc 10k mrc input 1k 1 f continued on next page.
LA1781M no.6038-12/48 continued from preceding page. pin no. pin function pin description equivalent circuit 33 mute drive output ?the muting time constant is determined by an external rc circuit as described below. attack time : t a = 10k c1 release time : t r = 50k c1 ?noise convergence adjustment the noise convergence can be adjusted when there is no input signal by inserting a resistor between pin 33 and ground. ?muting off function ground pin 33 through a 4k resistor. + 33 hole det soft mute band muting seek off v cc 0.1 f c1 50k 10k 50k mute amp. sd circuit 34 35 36 37 agc qd output qd input v ref ?the resistor r1 determines the width of the band muting function. increasing the value of r1 narrows the band. reducing the value of r1 widens the band. ?null voltage when tuned, the voltage between pins 34 and 37, v 34 - 37 , will be 0v. the band muting function turns on when |v 34 - 37 | 0.7v. v 37 = 4.9v 37 36 35 34 hole det band muting quadrature detector 0.1 f v ref r1 r2 v cc v cc c 390 1k 3pf if limiter amplifier 38 fm sd adj a 130 a current flows from pin 38 and, in conjunction with the external resistance r, determines the comparison voltage. 24 38 + -- sd r sd adj 130 a comparator s-meter continued on next page.
LA1781M no.6038-13/48 continued from preceding page. pin no. pin function pin description equivalent circuit 39 keyed agc am stereo buffer the keyed agc operates when the voltage created by dividing the pin 24 s-meter output voltage by the 6.4 and 3.6k resistors becomes lower than the voltage determined by the resistor between pin 39 and ground. this pin also is used as the am stereo if buffer pin. 24 39 + -- keyed agc s-meter 6.4k 3.6k comparator 1.3v 50pf 150 90 a v cc a m if out 41 hcc capacitor the hcc freq uency characteristics are determined by the external capacitor connected at this pin. 41 + 2200pf 20k 20k v cc 42 am l.c. pin this pin is used to change the frequency characteristics of the unneeded audio band under 100hz in am mode to produce a clear audio signal. note : the lc capacitor must be connected between this pin and v cc (pin 40). this is because the detector circuit operates referenced to v cc . the cutoff frequency f c is determined by the following formula. f c = 1/2 50k c 42 + -- det v cc v cc c 50k 50k 1k 1k 43 pilot detector inserting a 1m resistor between pin 43 and v cc will force the ic to mono mode. + 43 + v cc 30k 30k 30k 19khz 0 bias 1 f continued on next page.
LA1781M no.6038-14/48 continued from preceding page. pin no. pin function pin description equivalent circuit 44 if agc g1 ; used for time constant switching during seeks. ? reception = 2.2 f 300k ? seek = 2.2 f 10 the external capacitors are connected to v cc . this is because the if amplifier operates referenced to v cc . + 42 det 44 v cc v cc c 2.2 f 0.022 f 50k 50k 240k g1 10 seek on if agc 45 if output the if amplifier load 45 det pin 40 v cc pin 40 v cc 46 am antenna damping drive output wide band agc input i46 = 6ma (maximum) this is the antenna damping current. 46 v cc v cc 50pf 100 20k ant damping driver w.agc amp. 47 fm muting on level adjustment modify the value of the external resistor to adjust the muting on level. 47 + -- inverter v cc 30k r 140 a pin 24 mute continued on next page.
LA1781M no.6038-15/48 continued from preceding page. pin no. pin function pin description equivalent circuit 48 57 rf agc bypass rf agc rf agc rectification capacitor the low frequency distortion is determined as follows : increasing c48 and c57 improves the distortion but makes the response slower. reducing c48 and c57 aggravates the distortion but makes the response faster. + 48 + 57 + -- antenna damping v cc 5.6v 10k 3.3 f 47 f for agc use 50 51 if bypass fm if input due to the high gain of the limiter amplifer, care must be taken when choosing the grounding point for the limiter amplifer i nput capacitor to prevent oscillation. 50 51 2.6v 10k 10k 0.022 f 330 if in 52 if input the input impedance is 2k . 52 2k 100 53 56 if amplifier output if amplifier input ? input and output pin or the first if amplifier ? inverting amplifier v56 = 2v input impedance : r in = 330 v53 = 5.3v output impedance r out = 330 53 56 if out if in 2.75v 300 v cc 300 continued on next page.
LA1781M no.6038-16/48 continued from preceding page. pin no. pin function pin description equivalent circuit 54 49 mixer output : 130 a mixer input the mixer coil connected to the pin 54 mixer output must be wired to v cc (pin 40). the pin 49 mixer input impedance is 330 54 49 osc pin 40 v cc pin 40 v cc 330 55 58 w-agc in am sd adj n-agc in muting attenuation adjustment pin pins 55 and 58 include built-in dc cut capacitors. the agc on level is determined by the values of the capacitors c1 and c2. pin 55 functions as the sd sensitivity adjustment pin in am mode. the output current i55 is 50 a, and v55 varies depending on the value of the external resistor. the sd function operates by comparing v55 with the s-meter voltage. 55 58 + -- w-agc n-agc pin 62 v cc 30pf 50pf 50 a signal meter am sd c1 c2 mix in mix out 59, 60 63, 64 mixer output mixer input double balanced mixer. pins 59 and 60 are the mixer 10.7mhz output pins 63 and 64 are the mixer input. this is an emitter insertion type circuit, and the amount of insertion is determined by the capacitors c1 and c2. note :the lines for pins 63 and 64 must be kept separated from the lines for pins 59 and 60. 59 60 63 o s c 64 1st.if 30 v cc c1 c2 5pf 5pf rf amp 620 620 v cc continued on next page.
LA1781M no.6038-17/48 continued from preceding page. pin no. pin function pin description equivalent circuit 6 front end v cc am/fm switching pin 6 functions both as the fm front end v cc and the am/fm switching circuit. v6 voltage mode when 8v fm open am + 3 6 + -- fm.f.e agc am/fm switching circuit sd v cc 510 100k 3.3v gnd 8v 62 1st mix input first mixer input the input impedance is about 10k . 62 am 1st mix to rf a mp. 10k 2.1v 10 am 2nd osc crystal oscillator circuit the kinseki, ltd. hc-49/u-s and a c l of 20pf must be used. 10 10k 5.6v 20pf 33pf x tal to 2nd mix
LA1781M no.6038-18/48 block diagram 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 48 47 46 45 44 43 42 41 40 39 38 37 36 35 34 33 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 64 63 62 61 60 59 58 57 56 55 54 53 52 51 50 49 ant d buff am 1st osc agc amp noise pican input trig gate counter amp hpf ff 19k < 90k lpf snc mrc ff 19k < 0 ff 38k < 0 ff phase comp vco trig pilot det p-can sub dec mat rix vco stop main hc hcc ant d hole det mute drive amvsm am sd if buff fmvsm fm sd if limiter amplifier det if agc buff l.c. osc buff osc dc-c det afc clamp q.det mute amp mix am/fm mix rf agc wb agc tweet buff am fm vref seek sw sd/st ind keyed agc if reg am/fm sw w.b.agc rf agc amp input + + -- + + + + + + + + + + + + + + + ant d osc rf agc fe gnd 30k 10k 30k 18pf 300pf 6800pf 0.01 f 0.015 f 0.015 f 0.01 f 0.22 f 0.47 f 1 f 1 f 1 f am hc am level 1 f 1 f 20k 100k 5.6k 10k 100k 8200pf 50k 1k 100k 0.047 f 10.26mhz 10pf 5pf 18pf 1 f 0.022 f 0.022 f 0.022 f 0.01 f 0.47 f 1m + am osc mpx out pi.can adj sep.adj csb912jf104 am/fm s-meter gnd 5v snc hcc nc-in det out meter fm gnd nc mpx gnd n.c.mpx gnd mute drive 0.47 f 0.47 f 0.22 f 0.022 f 2.2 f 3.3 f 1 f 11k if7 100 f 2200pf afc in qd out qd in v ref fm sd adj. am lc chcc pilot det keyed agc 10k 10k 30k 240k 6.8k 0.1 f rfagc gnd v cc 0.022 f 0.022 f 0.022 f 100 h 47 f 15pf 15pf 100 h 0.022 f 30 100k 620 510k 20k 62pf 330 fc18 antd 1mh 30mh fm if in fm if out am if in fe if in 0.022 f 220 100 am mix out fm wb agcin am sd adj mute att fev cc 0.022 f 5pf 5pf 8pf 18pf 30 30 30k 100k 180w 9pf 39pf 100k 1000pf 100k 100 gnd 200k 1000pf 3sk263 0.1 f 0.022 f gnd 1000pf 1000pf 30k 22pf 22pf 0.022 f 100k v cc v cc 100f 0.022 f 0.022 f 200k 2k 300 fmif am gnd fmif am nc mpx v cc fm/am vsm right ch. left ch. am/fm osc buff fm gnd fm/am vt fm ant in am rf gnd am ant in am v cc seek am/fm sd stop fm st ind. 0.022 f to am stereo (if out) adj + + + + + ++ + 100k 100k 10k 10k 10k 2.2k 0.01 f 3sk583 1 f 22pf 22pf 7.2mhz 10 f 0.22 f 100pf 100pf 100pf 100pf 51k 0.22 f 200k 1k 68pf 2.2k 4.7k 51k 10 f 10 f 10 f 10 f 240k 240k 22k 22k 22k 22k 22k 22k 1k 10k 10k 1k 100k 100k 1.5k 100 f 100 f 5.6v 9.1v 100pf ci cl do rds adc mute r on sd/mono st ce lc867148 +b 12v l r v ss pd v dd fm in ci cl do fm/am ce am in lc7216m 20 19 18 17 16 15 14 13 12 11 1 2 3 4 5 6 7 8 9 10
LA1781M no.6038-19/48 ac characteristi cs test circuit 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 48 47 46 45 44 43 42 41 40 39 38 37 36 35 34 33 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 64 63 62 61 60 59 58 57 56 55 54 53 52 51 50 49 ant d buff am 1st osc agc trig gate hpf ff 19 < 90 k lpf snc mrc ff 19 < 0 ff 38k < 0 ff phase comp vco trig pilot det p-can sub dec ma trix vco stop main hc hcc ant d hole det mute drive amvsm am sd if buff fmvsm fm sd if limiter amplifier det if agc buff l.c. osc buff osc dc-c det afc ciamp q.det mute amp mix am/fm mix rf agc w.b. agc tweet buff am fm vref keyed agc ff reg fm/am sw w.b.agc rf agc + + -- + + + + + + + + + + + + + + ant d rf agc fe gnd osc 20k sw1 va1 va9 8v v cc va6 10k 20pf 300pf 6800pf 0.01 f 10 f 0.015 f 0.015 f 0.01 f 0.22 f 0.47 f 1 f ba sw4(t) 1 f am hc am level 1 f 1 f 20k 3pf 100k vr1 vr2 8v sw9 5.6k 8200pf 0.047 f 0.022 f 10.26mhz x tal 5pf 1 f 0.022 f 0.022 f 0.01 f 0.47 f 1m 50k 50k vd2 va3 fm/am ifbuff. vd4 sw5 4.3k 100k 100k + am osc mpx out pi.can adj sep.adj csb912jf104 am/fm s-meter gnd snc hcc nc-in det out fm s-meter n.c.mpx gnd mute drive 0.1 f 0.47 f 0.22 f 0.022 f 2.2 f 3.3 f 1 f 15k if7 100 f 2200pf afc in qd out qd in v ref fm sd adj. am lc chcc pilot det mute or adj keyed agc 10k 10k 22k 240k 6.8k 0.1 f rfagc if out b a if in sw3 sw2(i) mix gnd v cc 0.022 f 0.022 f 100 h 47 f 20k 0.022 f 0.022 f 100 h 0.022 f 30 100k 620 510 1k 30 25 50 300k 0.022 f 10pf 330 fc18 antd vd6 sw8 sw7 1mh 6.8mh fm if in fm if out am if in fe if in 330 200 300 0.022 f am mix out fm wb agcin am sd adj mute att fev cc v cc v cc 5pf 5pf 3pf 39pf 100k 50 10k 1m 100 100 gnd vt 0.022 f 0.022 f 1000 f 0.022 f 15pf jis dummy 30 50 65pf 30k right ch. left ch. am/fm osc buff va2 fm gnd fm v cc seek am/fm sd stop am st buffer fm st ind. adj vd1 200k 30k v cc 2 vd3 v cc 2 vd5 mrc-in v cc 8v v cc 3 hcc nc-in snc pg1 (ac1) + v cc 1 5v 100k sw6 + + ac5 + ac1 sg1 300 50 50 + ac3 sg3 + ac2 sg2 3pf 0.022 f 10k 10k v cc va7 8v sw10 10 f + 10k 1m va8
LA1781M no.6038-20/48 test conditions switch states parameter symbol sw1 sw2 sw3 sw4 sw5 sw6 sw7 sw8 sw9 sw10 current drain i cco -fm on b off b - on off off on - demodulation output v o -fm on b off b - on off off on - pin 31 demodulation output v o -fm31 on b off b - on off off on - channel balance cb on b off b - on off off on - total harmonic distortion (fm) thd-fm mono on b off b - on off off on - signal-to-noise ratio : if s/n-fm if on b off b - on off off on - am suppression ratio : if amr if on b off b - on off off on - att-1 on b off b - on off off on - att-2 on b off b - on off off on - muting attenuation att-3 on b off b - on off off on - separation separation on b off b - on off off on - stereo on level st-on on b off b - on off off on - stereo off level st-off on b off b - on off off on - main total harmonic distortion thd-main l on b off b - on off off on - pilot cancellation pcan on b off b - on off off off/on - snc output attenuati on attsnc on b off b - on off off on - hcc output attenuation 1 atthcc-1 on b off b - on off off on - hcc output attenuation 2 atthcc-2 on b off b - on off off on - input limiting voltage v in -lim on b off b - on off off on on muting sensitivity v in -mute on b off b - on off off on - sd sensitivity 1 sd-sen1 fm on b off b off off off off on - sd sensitivity 2 sd-sen2 fm on b off b on off off off on - if counter buffer output v ifbuff-fm on b off b off off off off on - v sm fm-1 on b off b - on off off on - v sm fm-2 on b off b - on off off on - v sm fm-3 on b off b - on off off on - signal meter output (fm) v sm fm-4 on b off b - on off off on - muting bandwidth bw-mute on b off b - on off off on - mute drive output v mute-100 on b off b - on off off on - n-agc on input v nagc on a on b - on off off - - w-agc on input v wagc on a on b - on off off - - conversion gain a.v on a on b - on off off - - oscillator buffer output v oscbuff-fm on a on b - on off off - - gate time 1 gate1 on - off a - on off off - - noise sensitivity sn on - off a - on off off - - nc effect sn-nc on/off - off a - on off off - - mrc output v mrc on - off b - on off off - - mrc operating level mrc-on on - off b - on off off - - practical sensitivity s/n-30 off - off b on on - - - - detection output v o -am off - off b on on - - - - pin 31 detection output v o -am31 off - off b on on - - - - agc f.o.m. v agc-fom off - off b on on - - - - signal-to-noise ratio s/n-am off - off b on on - - - - total harmonic distortion (am) thd-am off - off b on on - - - - v sm am-1 off - off b on on - - - - signal meter output (am) v sm am-2 off - off b on on - - - - oscillator buffer output v oscbuff-am 1 off - off b on on - - - - w-agcsen1 off - off b on on - - - - wide band agc sensitivity w-agcsen2 off - off b on on - - - - sd-sen1 am off - off b off off - - - - sd sensitivity sd-sen2 am off - off b off off - - - - if buffer output v ifbuff-am off - off b off off - - - -
LA1781M no.6038-21/48 usage notes 1. notes on v cc and ground pin 40 v cc for the fm if, am, nc, mpx, and mrc blocks pin 25 ground for the fm if and am blocks pin 14 ground for the nc, mpx, and mrc blocks pin 61 v cc for the fm front end, am first mixer, and first oscillator blocks *pin 6 v cc for the fm front end and agc blocks, and the am/fm switching pin pin 3 ground for the fm front end, first mixer, and first oscillator blocks 2. notes on am coil connection the v cc used for the first oscillator coil connected to pin 7 must be at the same potential as pin 61. connect to the ift connected with pin 45, and to the mix coil connected with pin 54. v cc must be at the same potential as pin 40. 3. am/fm switching pin 6 is also used as the fm front end and rf agc v cc pin 6 voltage mode 8 fm open am fig. 1 4. notes on the fm front end notes on interference rejection characteristics ? intermodulation characteristics the LA1781M applies two high-band agc functions to prevent im (the generation of intermodulation). these are the narrow agc (pin 58 : mixer input detection type) and the wide agc (for the pin 55 input), and this results in the antenna frequency characteristics shown in figure 2. the levels at which the agc functions turn on are determined by the capacitors attached at pins 55 and 58. fig. 2 v6pin 8 3.3 am fm am f -- agc sensitivity 50 70 80 90 100 110 60 -- 5 -- 4 -- 3 -- 2 -- 1 5 4 3 2 1 0 f -- mhz agc sensitivity -- db when f = 0, 98.1mhz the wide agc sensitivity when pin 39 is 5v. the narrow agc sensitivity when pin 39 is at ground.
LA1781M no.6038-22/48 ? notes on second-channel attenuation suppression keyed agc (3d agc) is a technique for achieving good characteristics for both intermodulation and secondchannel attenuation at the same time. when the desired signal is faint or nonexistent, the high-band agc level will be essentially 0, and as a result automatic tuning may malfunc tion and blocking oscillation may occur in the presence of strong interfering stations. keyed agc helps resolve these problems. this 3d agc technique uses information that has the following three frequency characteristics and is a unique sanyo-developed system for determining the high-band agc level. rf and ant circuit information : mixer input agc mixer circuit information : mixer output agc cf selectivity information : s-meter output ? 3d agc features feature merit only the narrow agc sensitivity (operation at f < 1.5mhz) is controlled by the field strength of the desired station. ? effective in resolving seco nd-channel attenuation problems. the narrow agc sensitivity is controlled by a voltage (v 23 ) that is under 0.5v. ? allows effective resolution of second-channel attenuation problems without under 0.5 v. degrading three-signal characteristics. the wide agc can operate even when v 23 = 0 (when the desired station is not present). ? seek operations may stop incorrectly due to the occurrence of intermodulation. ? it is possible to prevent the occu rrence of intermodulation in the rf tuning circuit and antenna in the pres ence of strong interfering stations, and blocking oscillation due to agc operation can be prevented. the narrow and wide agc sensitivities can be set independently. (see figure 3 and 4.) ? settings can be optimized for the field conditions. the system has two agc systems : narrow and wide agc. (see figure 5.) ? since the narrow agc operates for the desired station and adjacent stations, the wide agc sensitivity can be lowered and agc malfunction due to local oscillator signal can be prevented. 39 39 5v f -- agc on level (ant input) w-agc, n-agc -- f f -- agc on level (ant input) 50 70 80 90 100 110 60 50 70 80 90 100 110 60 -- 5 -- 4 -- 3 -- 2 -- 1 5 4 3 2 1 0 f -- mhz 7 1.0 10 7 5 3 2 100 7 5 3 23 25 frequency, f -- mhz -- 5 -- 4 -- 3 -- 2 -- 1 5 4 3 2 1 0 f -- mhz narrow agc on level -- db 140 120 110 100 90 80 130 70 pin 59 narrow agc and pin 55 wide agc input levels -- db wide agc on level -- db keyed agc keyed agc pin 58 capacitor : 10pf pin 58 capacitor : 47pf agc input level frequency characteristics such that v rf agc (pin 2) falls under 2v. wide agc on level frequency characteristics narrow agc on level frequency characteristics pin 55 capacitor : 3pf pin 55 capacitor : 10pf fig. 3 fig. 5 fig. 4
LA1781M no.6038-23/48 3d agc sensitivity characteristics fig. 6 figure 6 3d agc sensitivity - f, v 23 characteristics ? the wide agc sensitivity is determined by the antenna and rf circuit selectivity, regardless of v23. ? the narrow agc sensitivity is determined by the following. the total selectivity of the antenna, rf circuit, and mixer when v 23 0.5v the above selectivity and v 23 when v 23 < 0.5v ? the improvement in the second-channel attenuation corresponds to the area occupied by the narrow agc in the total agc sensitivity area. figure 8 on the next page shows the actual operation of the circuit. fig. 7 second-channel attenuation improvement desired station agc sensitivity 4 3 2 1 f narrow agc sensitivity v 23 (desired station field strength) wide agc sensitivity agc sensitivity ant in v in second-dhannel pad f d = 98.1mhz fu = 98.1mhz + f f -- agc on level (ant input) 50 70 80 90 100 110 60 -- 5 -- 4 -- 3 -- 2 -- 1 5 4 3 2 1 0 f -- mhz the fu input level at which antenna damping turns on -- db when f = 0, 98.1mhz
LA1781M no.6038-24/48 notes on 3d agc (keyed agc) fig. 8 ? the antenna damping current from the pin due to the pin diode flows when the v2 pin reaches the v cc - v be level. ? the narrow agc oper ates as follows. when pin v39 > pin v24 : the narrow agc turns off. when pin v39 < pin v24 : the narrow agc turns on. + 55 w-agc det 58 1 2 39 24 n-agc det + -- + -- v cc v cc ant dumping 90 a s-meter vs-meter
LA1781M no.6038-25/48 ? the LA1781M includes two agc circuits in its front end block. (1) antenna input limiter using a pin diode. (2) fet second gate control the agc input pin is pin 59, and the agc circuit turns on when a signal of about 30mvrms is input. agc activation the pin diode drive circuit turns on when vcc - v2 is greater than or equal to about 1v, and input limitation is applied to the antenna circuit. in application circuits, ther e will be an attenuation of about 30 to 40db. next, when an adequate current flows in the antenna attenuator pin diode, the inductance falls, the fet second gate voltage drops, the fet gm falls, and the agc operates. the recommended fet is the sanyo 3sk263, which is an enhancement-type mosfet. therefore, fu ll agc is applied when the voltage, v g2-s , between the second gate and the source is 0. note that if a depletion-type mosfet is used, agc will not be applied unless v g2-s is less than 0. ? mixer the mixer circuit in this ic is a double-balanced mixer with both balanced input and balanced output. input circuit type emitter input input impedance : 25 due to optimized device geometry, emitter current, the bias, this ic achieves the followi ng performance. mixer input usable sensitivity : 15db mixer input imqs : 90.5db (for an oscillator level of 200mvrms) * the mixer input imqs is defined as : fr = 98.8mhz, no input the interference 1 and 2 fu1 = 98.8mhz, 1khz, 30% modulation input levels such that fu2 = 99.6mhz, no modulation generated intermodulation output signal-to-noise ratio becomes 30db when an interference signal with the same level as the mixer input is input, and distortion occurs fig. 10 in the mixer. 59 64 60 63 62 osc mix imput mix out mix out mix input mix v cc mix mixer circuit v2 agc characteristics 0 2 3 4 5 6 7 8 1 9 --10 50 60 70 80 90 100 110 120 130 40 30 20 10 0 140 ant in -- db v2agc -- v fr = 98.0hz v cc = 8v ta = 25 c agc level due to the mosfet second gate : about 35db agc level due to the pin diode : about 35db range where the agc does not operate fig. 9
LA1781M no.6038-26/48 ? oscillator figure 11 shows the type of oscillator circuit used in this ic. it includes both an oscillator and an oscillator buffer. fig. 11 ? figure 12 shows the type of fm first if amplifier used in this ic. it is a differe ntial single-stage amplifier. fig. 12 specifications input impedance : 330 output impedance : 330 gain : 20db 5 4 vt 18pf 25pf 20pf v cc am/fm osc buffer out 56 53 + -- to mix 330 330 330 fm if input
LA1781M no.6038-27/48 5. fm if ? notes on the fm sd and sd adjustment the figure below presents an overview of the fm sd and the if count buffer. fig. 13 figure 14 shows the relationship between the fm sd, the if count buffer output, the s-meter, and the muting drive output. fig. 14 s-meter fm if hole clet muting drive output stereo ind band muting 39 24 33 23 26 + -- + -- + -- 4.9v r r r if count buffer if count output 2.5v 5v sd stereo/mono 5v v 23dc v 23ac v 26 v 33 v 38 v 24 5v larger values of r 33 smaller values of r 33 s-meter v 33 over 0.7v v 33 over 0.7v on as an sd signal sd on sd on stereo mono 0.7v off off if count buffer 5v 2.5v 0v if counter output off rds and other types of sd detection can be used by switching these modes. new la1784m functionality : for stereo input (when the v26 pin voltage is 0.7v), when this pin is shorted to ground (0.1v or lower) the ic will operate in forced mono mode.
LA1781M no.6038-28/48 ? transient response characteristics during automatic tuning the transient characteristics fo r sd and if count buffer on/off operation ar e determined by the time constants of the rc circuits attached to the following pins. (1) muting time constant : pin 33 (2) s-meter time constant : pin 24 (3) afc time constant : pin 34 there are two points that require consideration when using fast tuning. (1) the sd time constant due to the s-meter time constant since the current i24 (pin 24) varies with the field strength, the time constant also changes. there is no hysteresis in the comparator. if c24 is made smaller and the pin 24 voltage is used for the keyed agc pin 23, c23 must be chosen so that agc during keyed agc operation does not become unstable. fig. 15 (2) the sd time constant due to the pin 33 muting voltage time constant the changes in volume due to field fluctuation during weak field reception can be made smoother by setting the attack and release times duri ng soft muting operation. fig. 16 24 s-meter i 24 sd comparato r c 24 r 24 mute amp mute drive 10k 50k c 33 33 attack release muting time constants attack : 10k c33 release : 50k c33 sd sensitivity adjustment 0 10 20 30 40 50 630 26 22 18 14 10 34 resistance between the pin and ground -- k antenna input such that pin 5 goes high -- db fig. 17
LA1781M no.6038-29/48 however, when testing this stop sensitivity, note that when checking the waveform on the if count buffer output (pin 23), there are cases, such as that shown below, wher e current in the test system may be seen as flowing to ground and cause oscillation that causes the if count buffer output to go to the output state. fig. 18 ? fm muting control pin (pin 47) (r47 : 30k variable resistor) the -3db limiting sensitivity can be adjusted with r47. ? fm muting attenuation adjustment (pin 58) the muting attenuation can be switched between the three levels of -20, -30, and -40db by the resistor inserted between pin 58 and ground. (note that the exact values depend on the total tuner gain.) the noise convergence with no input is determined by the pin 58 voltage. r58 mute att open -20db 200k -30db 30k -40db the attenuation can be set by making r33 smaller as listed in the table above. fig. 20 if buffer amp if f.e. 5v 0.022 f the 10.7mhz feeds back through ground. test system capacitance 58 r 33 100 r 58 33 fm soft muting (1) --70 --40 --30 --20 --10 0 --50 --60 10 --20 --10 30 20 10 040 antenna input -- db output, noise -- db r47 = 7.5k det out noise 15k 10k 20k fig. 19
LA1781M no.6038-30/48 fig. 23 ? fm muting off function forcing this pin to the ground level turns muting off. fig. 24 + -- + -- 58 33 31 200k r v cc r r n-agc to mix out open 200k 30k mute drive limiter quadrature detector mute amp. (vca) det out 20 1 0 detecter output antenna input when the pin is at the ground level, the noise convergence will be 10db and the -3db limiting sensitivity will be about 0db . 58 58 fm soft muting (2) fm soft muting (3) --70 --60 --50 --40 --30 --20 --10 0 10 --60 --50 --40 --30 --20 --10 0 10 --70 --20 --10 0 30 40 20 10 antenna input -- db --20 --10 0 30 40 20 10 antenna input -- db output, noise -- db output -- db output -- db fig. 21 fig. 22 r47 = 7.5k det out noise 15k 10k 20k 200k r47 = 7.5k det out noise 15k 10k 20k 30k
LA1781M no.6038-31/48 ? hall detection the hall detection function detects the level of the pin 36 quadrature input signal and then applies peak detection to that result. the result is output from pin 33. this circuit has three effects. (1) it assures that muting will be applied for weak inputs with an antenna input of under 5db . the amount of attenuation is referenced to an antenna input of 60db , fm = 1khz, and a 22.5khz dev output, and is variable from 10db to 40db when there is no input. thus one feature of this circuit is that the weak input noise attenuation and the -3db limiting sensitivity for over 5db inputs can be set independently. (2) when the pin 36 quadrature input is a saturated input, the pin 36 noise level (va) is detected and a peak-hold function is applied to pin 33 (vb) for locations rapid fi eld strength variations and severe multipath occurs for fields that result in an antenna input level of over 5db . fig. 26 (3) unique features one unique feature of the LA1781M is that if there are adjacent stations such that f 1 = 98.1mhz and f 2 = 97.9mhz, a search operation will not stop at 98.0mhz. since v afc = 0v and v sm = 3.6v at 98.0mhz in the situations shown in figure 27 and 28, even though hall detection would normally not operate and sd would be high, in this ic the hall detection circuit will operate, v mute will be set to 1.2v (over 0.7v) and the sd signal will go low, thus preventing inco rrect stopping of the search. 36 33 + 00 0.1 f va vb hall detection output -- antenna input characteristics 0 2 3 4 1 5 --20 --10 20 10 030 antenna input -- db v 38pin -- v area muted by hall detection fig. 25
LA1781M no.6038-32/48 ? notes on the quadrature input level when a strong field is being received the quadrature signal input (pin 36 ) requires a 200mvrms input, and the detection transformer and the damping resistor between pins 36 and 37 must be designed. (we recommend the sumida sa-208 transformer and a 10k resistor between pins 36 and 37.) when the pin 36 input level falls below 160mvrms, the hall detection circuit operates and the pin 33 mute drive output voltage increases. therefore, when pin 36 input is fr om 160 to under 200mv rms du ring strong field reception, the muting circuit may or may not operate due to sample-to-sample variations between individual ics. furthermore, the sd function may not operate, and the audio output level may be reduced. incorrect operation due to sample-to-sample variations and temperature characteristics can be prevented by keeping the pin 36 voltage at 200mvrms or higher. 36 37 sg 10.7mhz la1888m 75 75 + 0.022 f pin 33 vmute -- qd input level 0 2 3 4 5 1 6 92 94 96 104 102 100 98 106 qd input level -- db vmute -- v thd -- % with pins 34 and 37 shorted. with 5v applied to pin 24. with a 10k resistor between pins 36 and 37 thd 1khz 75khz dev f -- khz f = 0 10.7khz with the resistorbetween pins 36 and 37 open. voltage between pins 37 and 34 (referenced to the pin 37 voltage) fig. 29 sa208 + LA1781M if input characteristics fig. 30 0.2 --0.2 --0.4 --0.6 --0.8 0.4 0.6 0.8 1 2 3 4 0 --20 --40 --60 --80 20 40 60 80 100 120 --100 --120 f 1 f 2 ant in unique featuers of the LA1781M hall detection circuit (1) 0 4 6 -- 1 0 1 2 2 97.7 97.8 97.9 98.0 98.1 98.2 98.3 frequency, fr -- mhz voltage between pins 37 and 34, v afc -- v pin 33, v mute -- v 0 4 6 2 pin 24, v sm -- v 0 4 6 8 2 pin 26 (sd) -- v when the tuner is moved in 50khz steps. with a 51k resistor between pins 37 and 34. with the sd sensitivity adjusted to be 20db . f 2 = 97.9mhz, 120db fm = 400hz, 22.5khz dev. f 1 = 98.1mhz, 120db fm = 1khz, 22.5khz dev. fig. 27 unique featuers of the LA1781M hall detection circuit (2) 0 4 6 -- 1 0 1 2 2 97.7 97.8 97.9 98.0 98.1 98.2 98.3 frequency, fr -- mhz voltage between pins 37 and 34, v afc -- v pin 33, v mute -- v 0 4 6 2 pin 24, v sm -- v 0 4 6 8 2 pin 26 (sd) -- v when the tuner is moved in 50khz steps. with a 51k resistor between pins 37 and 34. with the sd sensitivity adjusted to be 20db . f 2 = 97.9mhz, 40db fm = 400hz, 22.5khz dev. f 1 = 98.1mhz, 40db fm = 1khz, 22.5khz dev. fig. 28
LA1781M no.6038-33/48 r 36-37 detector output mpx out v o pin 36 ac level qdin open 330mvrms 235mvrms 10k 280mvrms 200mvrms ? band muting adjustment procedure the muting bandwidth can be modified as shown in figure 31 with the resistor rbw between pin 34 and 37. 6. am ? am agc system the LA1781M rf agc circuit takes its input from three sources : the wide agc pin (pin 46), the middle agc pin (pin 49) and narrow agc. there is also an if agc circuit. fig. 32 + 62 46 57 49 rf 52 31 + 48 44 42 r w 1st mix 10.7mhz cf 2nd mix 450khz cf if amp. det 1st osc x'tal middle agc in narrow agc in wide agc in ant dumping rf agc 47 f 3.3 f amp. if agc 2.2 f 240k v cc v cc 37 36 35 34 ++ 1 f 0.47 f 10k r bw r bw -- muting bandwidth 0 80 120 160 200 240 40 280 1.0 23 57 10 23 57 100 2 resistor r bw between pins 34 and 37 -- k bandwidth such that the pin 33 voltage 2 v -- khz ant in 98mhz 100db sa208 sumida fig. 31
LA1781M no.6038-34/48 the wide band agc circuit in this ic has the frequency characteristics shown above. the pin 46 input frequency characteristics are identical to those of the rf amplifier gate. this agc circuit serves to prevent distortion at the fet input when a strong signal is applied to the antenna circuit. the level at which the agc circuit turns on can be adjusted to an arbitrary level with the wide band agc adjustment resistor. a delayed agc on level can be handled by reducing the value of the adjustment resistor. fig. 35 am agc f characteristics 60 90 100 70 80 800 900 1100 1000 1200 frequency -- hz agc on level wide agc operates for wide band interference middle agc operates for interference within 70 khz of the received frequency. middle agc operates for interference within 70 khz of the received frequency. narrow agc operates at the received frequency. wide agc operates for wide band interference fig. 33 62 57 + v cc 0.022 f 30 620 1mh 100 h 100 h 30mh 15pf 15pf 47 f 100k 0.022 f wide band agc adjustment resisto r fc18 30 0.022 f 0.022 f 0.022 f 46 50 510 50 --6db sg antd wide band agc circuit 70 80 90 100 110 120 1.0 23 23 57 10 5 pin 46 input -- mhz anternna damping on input level -- db received frequency : 1mhz fig. 34
LA1781M no.6038-35/48 ? notes on am sd (pin 26) and the sd adjustment pin sd and the if buffer are operated by comparing the s-meter level (v24) and the 5v reference voltage as shown in figure 36. fig.36 figure 37 shows the relationship between the am sd, the if count buffer, and the s-meter. fig.37 55 24 23 26 am if + -- s-meter 100k 0.47 f 51k seek 5v 5v if buffer if buff amp. sd 0.022 f 100k 50pf comparator 50 a v cc v 23dc v 23ac v 26 v 55 v 24pin larger values of r 55 smaller values of r 55 5v pin 55 am sd adjustment pin off if buffer on sd on s-meter 0v am sd sensitivity adjustment 0 20 30 40 50 60 70 10 80 01020 40 30 50 resistance between pin 55 and ground -- k antenna input such that pin 26 becomes 5v -- db fig. 38
LA1781M no.6038-36/48 ? am high band cut and detector output level adjustment methods the pin 31 am and fm tuner output has an impedance of 10k in am mode and a few tens of ohms in fm mode. therefore, r31 is used to lower the am detector output level and c31 determines the am high band frequency characteristics. fig. 39 ? am stereo system pins fig. 40 31 30 + fm detector am detector v cc v cc 10k noise canceler input 50k r31 c31 45 39 v cc v cc ift 50pf 150 if amp. keyed agc gnd to the am stereo decode r 400mvrms 450khz output
LA1781M no.6038-37/48 ? am low band cut adjustment method the am low band frequency characteris tics can be adjusted with c42, which is inserted between pin 42 and v cc . since the detector is designed with v cc as the reference, c42 must be connected to v cc . fig. 41 7. noise canceler block ? the noise canceler input (pin 30) has an input impedance of about 50k . check the low band frequency characteristics carefully when determining the valu e of the coupling capacitor used. note that f c will be about 3hz when a 1 f capacitor is used in the application. ? pins 8 and 9 are used to set the noise detector sensitivity and the noise agc. it is advisable to first set the noise sensitivity for a medium field (an antenna input of about 50db ) with pin 8 (the noise sensitivity setting pin), and then set the agc level for a weak field (20 to 30db ) with pin 9 (the agc adjustment pin). if the noise sensitivity is increased, the agc will become more effective but, i nversely, the weak field sensitivity will be reduced. noise canceler 10khz overmodulation malfunction may be a problem. in particular, when an overmodulated signal is input, the noise canceler may, in rare cases, malfunction. this is due to the fact that the if detector output has a waveform of the type shown in figure 43 due to the bands of the if ceramic filters as s hown below. (here, the antenna input is 60db , the ceramic filters are 150khz 1 and 180khz 2, f = 10khz, 180khz dev.) the noise canceler reacts to the spikes (whiskers) generated due to this over modulation, which results in di stortion to the audio output. (the spike components due to overmodulation occur due to the bands of the ceramic filters in the tuner.) the following describes a method for resolving this problem. this incorrect operation due to overmodulation is prevented by removing the spike components due to this over modulation with a low-pass filter consisting of a 1k resistor and a 2200pf capacitor shown in figure 44. however, note that th e fm separation characteristics in the high band and the am frequency characteristics will change. fig.44 fig. 43 am detecter 42 + -- 50k 50k 10k 10k 10k c42 v cc to pin 31 31 30 + -- if output noise canceler input 1k 1 f 2200pf h1 w1 2.5ou --2.5ou --19.00ms 981.00 s if audio output f = 10khz,180khz dev detector output -- frequency --50 --30 --20 --10 0 10 --40 20 357 0.01 23 0.1 7 523 1.0 7 523 10 7 52 frequency -- hz detector output -- db fr = 100khz fm = 10khz 30%mod 0.1 f 0.1 f 0.022 f 0.047 f 80%mod c31pin = 6800pf with no c 31 used. 30%mod using sep 450h c 42pin = fig. 42
LA1781M no.6038-38/48 8. multiplexer block ? hcc (high cut control) frequ ency characteristics (pin 41) when the hcc function operates, the frequ ency characteristics of the output si gnal are determined by the capacitance of the external capacito r connected to pin 41. fig. 45 fig. 46 ? pilot canceler adjustme nt (pins 17 and 18) fig. 48 the pilot canceler signal waveform (pin 19) is a 19khz signal that contains no third harmonic as shown in figure 48. since this signal has the same phase as the pilot signal, no capacitor is required between pin 18 and ground. since it has no third harmonic component, excellent pilot cancellation can be acquired in both the left and right channels by adjusting with a variable resistor. 41 20k c to the matrix vo (db) f (hz) 2 c 20k 1 2 c 20k 1 f c = [hz] 17 30 -- 12 11 6800pf 3.9k 18 0.01 f 50k pilot cancel gate to the multiplexer ncoise canceler input frequency characteristics --60 --40 --30 --20 --10 0 --50 10 357 100 23 1k 7 52 2 3 10k 7 53 frequency, f -- hz attenuation, hcc -- db changes in the pin 41 capacitor capacitance (for a 100% high cut ratio) v cc = 8.0v f = 98mhz 100%mod 80db in 0.0022 f 0.0047 f 0.001 f 0.01 f 0 f fig. 47
LA1781M no.6038-39/48 ? separation adjustment (pin 19) fig. 49 the separation is adjusted by modifying the input level to the subdecoder with the variable resistor connected to pin 19. since only the sub-modulation level is changed by changi ng the variable resistor se tting, the monaural (main) output level is not changed. furthermore, degradation of high band separation in the decoder can be avoided if the impedance of the external capacitor (c) in the subchannel frequency band (23 to 53khz) is made sufficiently smaller than the variable resistor. 9. mrc circuit fig. 50 19 5k 0.047 f c to the subdecoder 20k large r + + 24 s-meter 32 27 fm s-meter mrc 6.4k 10k 30k 3.6k 75pf 1k dc buffer v cc 2 a 100 qmrc c27 v cc to the snc, pin 28 noise amplifiter high-pass filter with fc = 70 khz + amplifiter an external transistor equivalent to the 2sc536 is required reason : a qmrc level shifter is required to allow a simplified mrc circuit to be used in the LA1781M.
LA1781M no.6038-40/48 (1) when there is no ac noise on pin 32 v 24 = v 27 - v be qmrc v27 is about 2.5v when the antenna input is 60db or higher. (2) since the mrc noise amplifier gain is fixed, the mrc circuit is adjusted by reducing the ac input level. fig. 51 (3) the mrc attack and release ar e determined by c27 on pin 27. attack : 7 a c27 2 a c27 release : 500 c27 100 notes on the noise canceler the noise canceler characteristics have been improved by implementing the circuit that determines the gate time in logic. since the time constant in earlie r noise cancelers was determined by an rc ci rcuit such as that shown in figure 52, the rise time shown in figure 53 was influenced by the values of the resistor and capacitor used. as a result the noise exclusion efficiency was reduced by this delay in the rise time. in the LA1781M, this rise time was shortened by implementing the circuit that determines the gate time in logic, allowing it to reliably exclude noise. fig. 52 fig. 53 + 32
LA1781M no.6038-41/48 gain distribution (fm) this section investigates the gain in each block in th e LA1781M when the sanyo recommended circuits are used. (test conditions) ambient temperature : 26c antenna and mixer input frequency : 98.1mhz first and second if input frequency : 10.7mhz the input levels when v sm = 2v will be as follows. ant in : 19db mix in : 30db 1st if in : 42db 2nd if in : 60db when the gains for each block are determined accor ding to the above, the results are as follows. rf gain : 11db mix gain : 12db 1st if gain : 18db fig. 54 (am) this section investigates the gain in each block in th e LA1781M when the sanyo recommended circuits are used. (test conditions) ambient temperature : 26c antenna and mixer input frequency : 1mhz first and second mixer input frequency : 10.7mhz second if input frequency : 450khz the gains at each stage will be as follows. rf gain (ant in-pin62) : 17db 1st mix gain (pin62-pin56) : 8db 1st if gain (pin55-pin53) : 15db fig. 55 fm rf mix in 64 pin 1st if in 56 pin 2nd if in 51 pin ant in 11db 12db 18db am rf rf gain 1st mix gain 1st if gain 2nd mix gain 2nd if gain 1st mix 1st if 2nd mix 2nd if am det
LA1781M no.6038-42/48 input circuits for each stage [fm] ? mixer input ? first if input ? if input [am] ? first mixer input ? second mixer input ? if input ? del input 62 50 0.022 f 50 fr = rf 52 50 0.022 f 50 fr = 450khz 45 50 0.022 f 50 ift fr = 450khz 49 50 0.022 f 50 fr = 10.71mhz (f2nd osc + 0.45mhz) 63 64 75 0.022 f 75 v in actual measurement 56 75 300 0.022 f 75 fr = 10.7mhz 51 50 75 300 0.022 f 75 330 0.022 f fr = 10.7mhz
LA1781M no.6038-43/48 sample am tuner circuit with the lc72144 used together am 1st if step fm if 1 f osc 10.25nhz 10.7mhz 10khz, 11khz 10.7mhz 2 f osc 10.35nhz 10.8mhz 9khz, 10khz 10.8mhz rf cf cf cf 1st if 2nd mix 450k 300 if lc72144 xbuff fosc rf cf cf cf 1st mix 10.71mhz 2nd osc 1st osc if 10.26mhz 62 10k af af rf cf cf quadrature detector 10.7mhz if nc mpx rch lch 59 56 53 49 54 52 31 60 63 64 60 56 53 51 59
LA1781M no.6038-44/48 crystal oscillator element kinseki, ltd. frequency : 10.26mhz cl : 20pf model no. : hc-49/u-s coil specifications sumida electronics, ltd. [am block] am filteer (sa-1051) am osc (sa-359) am if1 (sa-264) am if2 (sa-1063) am loading (sa-1062) am ant in (sa-1048) am rf amplifier (rc875-222j) [fm block] fm rf (sa-1060) fm ant (sa-1061) fm osc (sa-1052) fm mix (sa-266) fm det (sa-208) 1 23 64 3 2 4 16 s 3 2 4 16 s ss 3 2 4 16 s 3 2 4 16 s 3 2 4 16 s 0.1 2uew 3 2 4 16 s s 3 2 4 16 s 3 2 4 16 s 3 2 4 8 7 16 s s c1 c2 3 2 4 16 ss
LA1781M no.6038-45/48 the toko electric corporation [am block] am filteer (a286lbis-15327) am osc (v666sns-213by) am if1 (7psgtc-5001a = s) am if2 (7psgtc-5002y = s) am loading (269ans-0720z) am ant in (385bns-027z) am rf amplifier (187ly-222) [fm block] fm rf (v666sns-208aq) fm ant (v666sns-209bs) fm osc (v666sns-205apz) fm mix (371dh-1108fyh) fm det (dm6000deas-8407glf) 0.1 2uew 1 23 64 3 2 4 16 0.1 2uew 3 2 4 16 0.05 3uew 3 2 4 16 0.05 3uew 3 2 4 16 0.05 3uew 3 2 4 16 0.06 3uew 3 2 4 16 s s 0.1--2uew 3 2 4 16 s 0.1--2uew 3 2 4 16 s 0.12--2uew 3 2 5 4 16 s s 0.07--2uew 3 2 4 16 0.07 2muew
LA1781M no.6038-46/48 56 0.022 f 0.022 f 300 75 75 330 v in 53 v.v. 1k 33 330 v.v. 59 60 0 10 10 --20 140 --20 140 0 --60 --50 --40 --30 --20 --10 0 fm i/o characteristics --70 2 1 4 3 6 5 8 9 7 --70 --60 --50 --40 --30 --20 --10 --60 --50 --40 --30 --20 --10 1 2 3 4 5 6 0 7 10 --20 0 20 40 60 80 100 120 0 20 40 60 80 100 120 0 20 40 60 80 100 120 50 60 70 80 90 100 110 0 20 40 60 80 100 120 0 20 40 60 80 100 120 0 20 40 60 80 100 120 140 antenna input -- db output, noise, am output, lr output -- db fm i/o characteristics fm sensitivity suppression 0 2 1 4 3 6 5 8 9 7 10 --20 140 antenna input -- db hcc, snc, rf agc, muting voltage, s-meter voltage, v sm -- v antenna input -- db output, noise -- db antenna input -- db total harmonic distortion, thd -- % fm distortion v sm v mute v hcc v snc out30% mod fm = 1khz 100% fm = 1khz 22.5k dev input from pin 64 only fm = 1khz 30% am out r ch l ch noise noise noise am out mute off snc, hcc off ant in 1st if if ant cf + if 1st if if out fu120 fu100 fu90 rf agc --70 10 0 8 --20 140 input -- db output, noise, am output -- db 60 70 80 90 100 110 70 80 90 100 110 120 60 120 40 50 100 110 60 70 80 90 120 mixer input -- db mixer output -- db 40 120 first if input -- db first if output -- db --20 140 input -- db dcv -- v fm gain distribution (1) fm gain distribution (2) mixer i/o characteristics first if i/o characteristics
LA1781M no.6038-47/48 56 0.022 f 0.022 f 0.022 f 300 75 75 330 v in 53 v.v. 80db in 20 100 30 --40 --20 100 --40 100 --40 --30 --20 --10 0 first if frequency characteristics --50 40 30 60 50 80 70 90 --10 0 10 20 10 20 30 40 0 10 7 1.0 23 57 10 22 357 100 020406080 --20 0 20 40 60 80 --20 0 20 40 60 80 0 20 40 60 80 100 120 --20 20 0406080 0 20 40 60 80 100 120 3 frequency -- mhz first if output -- db fm antenna input temperature characteristics (1) fm antenna input temperature characteristics (3) 0 100 200 300 400 --40 100 frequency -- mhz first if output -- db ambient temperature, ta -- c antenna input -- db ambient temperature, ta -- c s/n, am output -- db agc on, separation, input level -- db fm antenna input temperature characteristics (2) agc on level separation am out s/n v cc = 8.5v f = 1mhz mod = 1k 30% v cc = 8.5v f = 1mhz mod = 1k 30% 80% v cc = 8.5v f = 1mhz 80db in fm = 1khz 80% fm = 1khz 30% rf agc if agc vsm out noise 40db in 20db in mute att s/n = 30db -3db ls 75khz (100%mod) 22.5khz (30%mod) 0 50 --100 --80 --60 --40 --20 20 --40 100 ambient temperature, ta -- c separation, sep -- db 0 1.0 2.0 3.0 4.0 5.0 6.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 0 7.0 --20 0 100 120 20 40 60 80 140 ant input, in -- db agc, s-meter voltage -- v --20 140 ant input, in -- db total harmonic distortion, thd -- % --20 140 ant input, in -- db output, noise -- db fm antenna input temperature characteristics (4) am i/o characteristics am dc characteristics am distortion
LA1781M ps no.6038-48/48 sanyo semiconductor co.,ltd. assumes no responsib ility for equipment failures that result from using products at values that exceed, even momentarily, rate d values (such as maximum ra tings, operating condition ranges, or other parameters) listed in products specif ications of any and all sanyo semiconductor co.,ltd. products described or contained herein. sanyo semiconductor co.,ltd. strives to supply high-qual ity high-reliability products, however, any and all semiconductor products fail or malfunction with some probabi lity. it is possible that these probabilistic failures or malfunction could give rise to acci dents or events that could endanger human lives, trouble that could give rise to smoke or fire, or accidents that could cause dam age to other property. when designing equipment, adopt safety measures so that these kinds of accidents or e vents cannot occur. such measures include but are not limited to protective circuits and error prevention c ircuits for safe design, redundant design, and structural design. upon using the technical information or products descri bed herein, neither warranty nor license shall be granted with regard to intellectual property rights or any other rights of sanyo semiconductor co.,ltd. or any third party. sanyo semiconductor co.,ltd. shall not be liable f or any claim or suits with regard to a third party's intellctual property rights which has resulted from the use of the technical information and products mentioned above. information (including circuit diagr ams and circuit parameters) herein is for example only; it is not guaranteed for volume production. any and all information described or contained herein are subject to change without notice due to product/technology improvement, etc. when designing equi pment, refer to the "delivery specification" for the sanyo semiconductor co.,ltd. product that you intend to use. in the event that any or all sanyo semiconductor c o.,ltd. products described or contained herein are controlled under any of applicable local export control laws and regulations, such products may require the export license from the authorities conc erned 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 in formation storage or retrieval system, or otherwise, without the prior written consent of sanyo semiconductor co.,ltd. this catalog provides information as of july, 2009. specifications and informat ion herein are subject to change without notice. 50 50 50/3 50/3 50/3 30 v in 15pf ant in 65pf jis ant. dummy fu = 1040khz fm = 400hz 30% f d = 1mhz fm = 1khz 30% 50 50 50/3 50/3 50/3 30 v in 15pf ant in 65pf jis ant. dummy fu = 1400khz fm = 400hz 30% f d = 1mhz fm = 1khz 30% --60 --40 --20 0 --60 --40 --20 0 am second-channel interference rejection characteristics am second-channel interference rejection characteristics --80 20 40 60 80 100 120 60 80 100 120 140 ant input, in -- db output, noise -- db --80 20 40 140 ant input, in -- db output, noise -- db desire mod on 40khz desire mod off 100db 100db 80db 80db 40db 60db 40db 60db desire mod on 400khz desire mod off 100db 40db 100db 80db 80db 40db 60db 60db

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