6 sa fi ity ay FM IF System a BA4234L BA4235L The BA4234L and 4235L are single-chip FM IF systems with their S-shaped FM discrimination curves opposite (symmet- tical) to each other. The FM section of the devices consists of a differential IF arnplifier, double- balanced quadrature detector, and IF muting circuit for weak signals. The AM section consists of a local oscillator, double-balanced mixer, IF amplifier, detector. and AGC circuit. The devices also contain an audio amplifier and LED drivers for FM/AM tuning indicators. Features . Two different S-shaped FM discrimi- nation curves are available depend- ing on the AFC circuit used: reverse curve with the BA4234L, and forward curve with the BA4235L. sy. 2. oe supply voltage range of 3.0 12V. 3. Built-in AM local oscillator, mixer, and detector circuits assure stable AM operations from LW through SW. 4. High margin to AM input overload (with shunt AGC). 5. Built-in muting circuit for a weak FM signal reduces inter-station white noise and off-tuned side peaks. The muting circuit can be turned on or off with an external switch. 6. Built-in FM/AM tuning indicator drivers with direct LED driving capability. 7. Single-pin output for the FM and AM circuits allows coupling to the follow- ing stage (MPX, etc.) without a selector switch. 8. Exclusive frequency response setting pin for the AM circuit allows the FM and AM circuits to have independent frequency responses.: This facilitates coupling to the MPX circuit. 9. Switching between FM and AM modes. can be performed with OC level switching. Applications FM/AM portable radios Radio cassette recorders Home stereo systems Car stereo systems (ROHN CORP O7E D ff 7828999 oone702 7 ff Dimensions (Unit: mm) 22.0 %0? 9.90.5 f+1.270.2 0.55 J T= 7 7-08-87 21,59:20.3 2.75:0,25 13 7 9 113 16 17 24 6 8 10 12 14 16 18 Fig. 1 Block Diagram sw ose} fare} By Vee ou 0} [ir Ta] AM Mix OUT OND Eh BA42341L BA4235L s{e) am iF ww FM ie [7 FM/AM 4 __sSF AMP |e ]avPass BYPASS a] T 10] FM QUAD AF our [Tipe 12] Vee mute [13] 14] AM DET OUT acc [15] ) [16] AM AF IN vente Brg GND Fig. 2 Absolute Maximum Ratings (Ta=25C) Parameter Symboi | Umits | Unit Supply voltage Vec | 16 : Vv Power dissipation Pd 550 mw Operating temperature range Topr 25~75 c Storage temperature range Tstg -55+125 c * Derating is done at 5.5mW/C for operation above Ta=25C Recommended Operating Conditions Parameter Symbol | Min. Typ. Supply vottage Vee 3.0 6.0 12 Max. | Unit | Conditions 33ROHM CORP O7E >i 7928979 0002703 9 ff a T-77-05-07 Electrical Characteristics/FM Section (Ta=25C, Vec=5.5V, Vin=100dBzV, fin=10.7MHz, fm=1kHz, Af=22.5kHz) Parameter [| Symbol [ Mn | Typ | Max. | Unt | Conditions | Test circut Quiescent current io Fo. Bm MUTE OFF i Fg 3 Detector output Vor | 60 + 120 1 mv i _ Fg 3 E Total harmome aistortan : THD : _ 006 028 % ' - Fig 3 Signal-to-noise ratio 1 SiN 64 70 = 0B = Fig 3 sl Limiting sensitwity ot Vin(im) 28 a2 36 dBuV | Voyr= 308 Fig.3 3 LED turn-on sensitvity VintieD) 45 50 55 dBuV heo=tmA i Fig 3 F - Norse under no input i N -20 -30 _ d8 Vin= -20dBuV : 1 Fig 3 > Norse rejection ratio : NS -38 - _ dB MUTE ON/OFF i Fig 3 a a Electrical Characteristics/AM Section (Ta=25C, Vcc=5.5V, Vin=1MHz, fm=1kHz, MOD=30%) a Parameter ; | Symbol Min Typ. Max. Unit Conditions | Test circut Detector output Vour 60 9 | 125 | ma - Fg 3 Total harmonic distortion THD - 06 2 % _ Fig 3 Signal-to-noise ratio S/N 44 52 ~ a8 Fg 3 Maximum sensitivity 1 Vinwax 9 13 17 dBuv Vour= 10mv Fig 3 LED turn-on sensitivity . Veo! 19 24 aBuv lLeo= IMA Fig 3 fe NG Test Circuit Application Board Schematic Diagram FM am? 1 Veco FM.am ? Vec 6V yr I : 0.01 nF . ] on me | 0.01 0 Olue L R r . + ze, wed] ooicg. PM MET al ee fe .CF, , ; ; r aE Th pals : . : Sie softs! yon i pea T cetqu if 0,47aF z So t | Poanapaadna a A - i 510 : Ry p 2 an 13.222 | | i are i BA4234L/BA4235L | | 4 pore eee wo a aoe - ot e $4 wh $25 "nS tg bea eth Sar Fs iS Lt <t 4 3 309 0.0224 = =] s Te ey i : t ' BS } i os 1 = a - a | tf Le ot la 0.022 uF : = MUTE 3 4 Analzee OFF ON AM IN FM IF IN T, :AM OSC T, 0AM IFT T, :FM OET CF;. AM ceramic filter CF,: FM. ceramic filter CF2: AM ceramic filter Note: The electrical charactenstic Fig. 3 Fig. 4 curves are obtained from this application circuit. 34 : ROHM CORP O7E D ff 7828999 OODe7O4 oO { Application Example 9 4 ; ; oon 7 FM/AM cover our TO Ver 6 + 10a t t t m) LED on ! + t + 0.4igF HE \Gur FM ANT ong 1 t 7,4M.08 | 220 uF 1 be te | cs oe ie we $e b Tt BT bd peel i uF y 4 6 3 1? 12 : 1 10 Wa 15 6 py & OUT wr Let exrae. lor =p rwam sael euwex Te TT A Baaaty eT BA4234L nlp tye BAISS2 = ET P BA4413 = ' BA4235L x BA1332L [- C6 govt 5 + 9 + to 8 | nat, a . 0.01S= 33.380 osc aie al eT ' HP be ote ' + rae, Pill { Upper neterodyne BA4234L I Lower heterodyne BA4235L T, 1 FM iFT T, AM IFT 22000 (alee poset | Fo CHECK T, 2 AM OSC sd arc T, . FM OET 3 ; CF. CF, FM ceramic filters Fig. 5 CF; AM ceramic filter Precautions for Use 1..Leakage from AM local oscillation or noise applied to the AM IF input pin (pin 6) may cause a tuning indicator drive error or a sensitivity drop. Use the shortest possible wiring path from the AM ceramic filter output to the IF input pin (pin 6). 2. Ground the FM detection coil at the output section GND or at Vcc. If it is grounded at the input section GND, unstable operation may occur Specifications of Inductors 1 Tz FMIFT (455kHz) 2150-2173-157 (by Sumida) 64 26 ee3 4{-. cF 3-2 971 ali 4 2-1 79t Vee ' by Wire type 0.06UEW tnp C= 180pF Q== 10020% Fig. 7 Electrical Characteristic Curves u Veen { FM MUTE OFF 0 et = nee 4 Leen = 1 (em z g | 5 6 -| | Be wa a 2 i : ! ' I 0 2 4 6 & 10 2 SUPPLY VOLTAQE : Voc() Fig. 10 Quiescent current vs. supply voltage because of feedback. 3. When observing the S-shaped FM discrimination curve with an oscillo- scope and sweep generator, turn off the muting. If the muting is left on, the muting circuit time constant may Cause an observation error. 4. Note that the FM muting level varies depending on the noise level at the FM front end. 5. The value of the stabilizing resistor for 2. Ts: AM OSC coil 2157-2239-295 (by Sumida) 31 100t voe3 4t-~ 6-4 7t 20 4 Wire type 0.06UEW end {1 es} te L==250#H Q280 Fig. 8 Voos6V FM MUTE OFF 9-5 =B 0 BTS 00 AMGIENT TEMPERATURE | Ta(C} Fig. 11 Quiescent current vs. ambient temperature the AM local oscillator should be from 0 to 470. 6. A ceramic discriminator can be used in place of the FM quadrature coil to allow for an alignment-free FM IF circuit. BA42346L BA4235L @ 10 GDA10.7MG4 (MURATA) 3 wns fore 3 Ts FM DET (10 7MHz) 2153-409-090 (by Sumida) (SUMIDA) c+ Ion o4 3-1 12t 203 Wire type 0, 12UEW Vec 10st 06 C=100pF Q=105 Fig. 9 70 s 8 SENSITIVITY ; VedduV) & 2 10 4 6 14 SUPPLY VOLTAGE : Voc () Fig. 12 FM sensitivity vs. supply voltage 356X ROHM CORP O7E > ff 7828999 oooe7os 2 ff Electrical Characteristic Curves 70 VocssV f= 10, 7MHe tam the & 7 DEV 3056 7 _ i LED ON SENS > - . . an | r z i i > 4 : E 348 LIMIT SENS 5 ot wy vn t 20 10, 7 9 23 0 6 0 75 +100 AMBIENT TEMPERATURE : Ta (C} Fig. 13 FM sensitivity vs. ambient temperature MUTE. OFF VoomV | farl0.7MHe S+N y tam ikHe = .| DEVe30% g = 2 3 VY ut < -0 aN 5 Qo > 5-60 a 5 N o -80 ~10 20 0 6 8 10 i2 INPUT VOLTAGE : Voi (d8u) Fig. 16 FM detector output vottage (muting off) vs. input voltage 1.2 . Vocm6 flO. 7H Sia Va 100d #1.0 tee | z DEV 30% 0.8 5 Boe fa d 4 20.2 0 50-25 0 6 50 6 100 AMBIENT TEMPERATURE : Ta(C) Fig. 19 FM total harmonic distortion vs. ambient temperature B t far}, 7M Vee 100dBV om thee DEV=30% & \ & OUTPUT VOLTAGE. : Vour(mv) 8 2 4 8 10 12 14 6 SUPPLY VOLTAGE : Voc (V} Fig. 14 FM detector output voltage vs. supply voltage Voces6V | far l0. MHz S+N fame (kHz ORV 3056 | 3 ! & ouTeUuT VOLTAGE + Vour (08) & 4 ! & 100 0 6 80 100 120 INPUT VOLTAGE : Va (dB) Fig. 17 FM detector output voltage (muting on) vs. input voltage hr a ee | INPUT VOLTAGE : Vm (dV) Fig. 20 FM/AM rejection ratio vs. input voltage T-77-05-07 120 Voomev fm 10, 7M DEV=30% __ en 8 & srayiiduiy 4) PUB JY | OUTPUT VOLTAGE : Vasr(m) & 8 9 ~3 0 a 50 B 100 AMBIENT TEMPERATURE : Ta(C) Fig. 15 FM detector output voltage vs. ambient temperature b fm0, 7a Vee 1000 fam ike q OEV==30% o te TOTAL HARMONIC DISTORTION ; THD (96) so Ss 99 6 8 10 12 14 SUPPLY VOLTAGE : Yoo () Fig. 18 FM total harmonic distortion vs. supply voltage 100 aUTE ON | Voomev far, 7MHe - hy Vas S0daV 80 DEV= 30% 1 8 pb Ps OUTPUT VOLIME + Vout (dB) & _ f\ AINA A MUTE OFF V a =m0 0 2m 0 60 DETUNING FREQUENCY : Of (kHz) Fig. 21 FM detector output voltage vs. detuning frequency 36a feats.) Electrical Characteristic Curves ; Vouryd@) 1 Cl OUTPUT VOLTAGE 10 100 Tk 10k 100% MODULATION FREQUENCY ; fm(Hz) Fig. 22 FM detector output vollage vs. Modulaton frequency & Voom 6V far 1000kHr tm kHz 50 MOD= 3096 7 ~% 2 8 39 LED Of SENS] 5 ss! Bx 4domy OUTPUS SENS- 8 " to a ie % 2 0 3 50 % 100 AMBIENT TEMPERATURE : Tai C} Fig. 25 AM sensitivity vs. ambient temperature f i Voomy ttm 1000kHz : caine S+N M0D= 3056 yr ~ In V\ LM NLT 3 -2 0 OUTPUT VOLTAGE , View (48) ' 3 SS a INPUT VOLTAQE : Vn (dV) Fig. 28 AM detector output voltage vs. input voltage 100) TOTAL HARMONIC DISTORTION : THD(%) ~ w xn ROHM CORP O7E D Bovazasss OOOe?Ob 4 i ven Vocse6V fm 10, Meg Vous 100dBuV Cd | ' Ln 94 oa % 10 Im 150 DEVIATION : DEV iz kHz) Fig. 23 FM total harmonic distortion vs. deviation 120 f= 1000KMz Vass 740 few THz 00 MO00= 30% 7] zBiN 5 60 3 se e a 2 93 4 12 14 TOTAL, HARMONIC DISTORTION : THD (96) 6 a 10 SUPPLY VOLTAGE : VociV} Fig. 26 AM detector output voltage vs. supply voltage Vocm6v far 1000kHz Cor lkhe g a 8 MO0O= 60% rf p+ _// MOD = 10% NO ~ i INPUT VOLTAGE : VeidBaV Fig. 29 AM total harmonic distortion vs. input voltage 0 2a 4 60 80 100 120 T-77-05-07 & & 8 LED SENS SENSITIVITY : Ve(aBuvy 8 3s 1 6 SUPPLY VOLTAGE : Ver V Fig. 24 AM sensitivity vs. supply voltage Vocam6V | '= 1000kHz | Voom 74d mth MOD 3096 | 8 8 8 & OUTPUT VOLTAGE | Vous imv) 8 0 i 50 ~2 P4.) 50 75 100 AMBIENT TEMPERATURE : Ta C Fig. 27 AM detector output voltage vs. ambient temperature 8 3 - TOTAL HARMONIC DISTORTION ; THD (%) a n 6 SUPPLY VOLTAGE : Voc V Fig. 30 AM total harmonic distortion vs. supply voltage 37fe Electrical Characteristic Curves ROH CORP O7E D ff 7828999 Cooa707 & ff 12 Vocms6 foe | OD0kHz ~ Vem 74dQuV & 10 faa {chee 6 MOD= 3096 = g 8 z= 5 Be: 3 { 3 4 @ 22 | 0 i -~50 3 a # Pi) 100 AMBIENT TEMPERATURE : Ta(C) Fig. 31 AM total harmonic distortion vs. ambient temperature | ~ OUTPUT VOLTAGE. Vout (dB) \ I a x 20 tee Bets at 2 fF 5 100 1k MOOULATION FREQUENCY : fm(Hz) Fig. 34 AM detector output voltage vs. modulation frequency > TOTAL HARMONIC DISTORTION > THOX96) a 1s %6 100 MOOULATION FREQUENCY : tmi(Hz} Fig. 32 Total harmonic distortion vs, modulation frequency TOTAL HARMONIC DISTORTION : THO(96) we s a ~ T-77-05-07 100 40 60 80 MODULATION : MOD (96) Fig. 33 AM total harmonic distortion vs. modulation frequency av 7 2 a 7 P 3 gy a q a 38