Ordering number : EN8271 LA1837M Monolithic Linear IC Single-Chip AM/FM Tuner IC for Home Stereo Systems http://onsemi.com Overview The LA1837M is a single-chip AM/FM tuner IC that provides AM and FM IF and multiplex decoding circuits for electronic tuning and was developed for use in home stereo systems. It provides both SD and IF counting techniques for optimal implementation of automatic station selection. Features • On-chip MPX VCO circuit (no external components required). • Adjacent channel interference rejection function (third order and fifth order). • Supports both the SD and IF counting technique (built-in SD speedup function). • The AM and FM SD sensitivity can be set independently. • The AM and FM output levels can be set independently. • Improved basic FM reception performance. Functions • AM: RF amplifier, mixer, oscillator, IF amplifier, detector, AGC, oscillator buffer, S-meter, narrow band SD, IF buffer • FM IF: IF amplifier, quadrature detector, S-meter, SD, S curve detection, IF buffer output • Multiplex stereo decoding: PLL stereo decoder, stereo indicator, forced monaural, VCO stop function, post amplifier, audio muting, adjacent channel interference rejection function Specifications Maximum Ratings at Ta = 25°C Parameter Maximum supply voltage Allowable power dissipation Symbol Conditions VCC max Pd max Ta≤70°C* Ratings Unit 12 V 550 mW Operating temperature Topr -20 to +70 °C Storage temperature Tstg -40 to +125 °C *: Mounting board: 114.3×76.1×1.6mm glass epoxy board Stresses exceeding Maximum Ratings may damage the device. Maximum Ratings are stress ratings only. Functional operation above the Recommended Operating Conditions is not implied. Extended exposure to stresses above the Recommended Operating Conditions may affect device reliability. Semiconductor Components Industries, LLC, 2013 May, 2013 92706 / O3105 MS OT B8-3807 No.8271-1/9 LA1837M Operating Conditions at Ta = 25°C Parameter Symbol Recommended supply voltage VCC Operating supply voltage range VCC op Conditions Ratings Unit 9 V 7.0 to 11.0 V Electrical Characteristics at Ta = 25°C VCC = 9.0V, in the specified circuit. Ratings Parameter Symbol Conditions Unit min typ max [FM Mono Characteristics] fc = 10.7MHz, fm = 1kHz, with the coil adjusted so that VAFC - VREG = 0V. Current drain Demodulator output ICCO-FM VOFM No input 18 31 44 100dBµ, 100% mod, pin 16 output 730 1100 1460 mVrms mA -1.5 0 +1.5 dB % Channel balance C.B-mono 100dBµ, 100% mod, pin 16 output / pin 17 output Total harmonic THDFM1 100dBµ, 100% mod, pin 16 output 0.3 1.3 distortion (mono) THDFM2 100dBµ, 200% mod, pin 16 output 1.0 5.0 S/NFM 100dBµ, 100% mod, pin 16 output 72 80 dB 100dBµ, AM 30% mod, pin 16 output 45 65 dB Referenced to 100dBµ, 100% mod, the input for output 26 32 38 dBμ 51 60 69 dBμ 100dBµ 85 120 170 kHz 100dBµ, pin 13 output 80 120 160 mVrms 0 0.1 0.5 V 100dBµ, pin 11 output 3.6 4.3 5.0 100dBµ, 100% mod, the pin 16 output 75 85 dB dB Signal-to-noise ratio AM rejection ratio Input limiting voltage AMR -3dBL.S % is -3dB down. LED on sensitivity LED on bandwidth IF counter buffer output S-meter output SDON-FM SDBW VIFBUFF-FM VSM FM1 VSM FM2 Muting attenuation Mute Alt 0dBµ, pin 11 output V [FM Stereo Characteristics] fc = 10.7MHz, 100dBμ, fm = 1kHz, L+R = 90%, pilot = 10% Separation: L SepL Lmod. pin 16 output / pin 17 output 30 45 Separation: R SepR Rmod. pin 17 output / pin 16 output 30 45 Stereo on level STON The pilot mod such that V7 < 0.7V 1.3 2.7 Stereo off level STOFF The pilot mod such that V7 > 4.5V 1.5 Total harmonic THD main L+R mod. Pin 16 output 0.3 fs = 113kHz, Vs = 90%, Pilot = 10% 40 dB 40 dB dB 5.0 % % 1.3 % distortion (main) Adjacent channel Brej-3rd interference rejection ratio Pin 16 output, versus L-R mod. 1kHz demodulator output Brej-5th fs = 189kHz, Vs = 90%, Pilot = 10% Pin 16 output, versus L-R mod. 1kHz demodulator output [AM Characteristics] Current drain ICCO-AM 15 25 35 mA 23dBµ, 30% mod, pin 16 output 100 180 360 mVrms VOAM2 80dBµ, 30% mod, pin 16 output 200 320 500 mVrms S/N AM1 23dBµ, 30% mod, pin 16 output 18 22 dB S/N AM 2 80dBµ, 30% mod, pin 16 output 49 55 dB Total harmonic THD AM 1 80dBµ, 30% mod, pin 16 output 0.4 1.2 distortion THD AM 2 80dBµ, 80% mod, pin 16 output 1.0 4.0 % LED-ON sensitivity SDOn-AM 17 27 37 dBμ Output detector VOAM1 Signal-to-noise ratio No input % Oscillator buffer output VOSC-AM No input, pin 30 output 110 160 220 IF counter buffer output VIFBuff-AM 80dBµ, non-mod, pin 13 output 160 220 300 mVrms ST IF output VSTIF-AM 80dBµ, non-mod, pin 7 output 16 34 48 mVrms 0 0 0.2 V S-meter output VSM-AM 0dBµ, non-mod mVrms No.8271-2/9 LA1837M Package Dimensions unit : mm 3073C Block Diagram No.8271-3/9 LA1837M Coil Specifications • AM oscillator (for the DUT) HW-50425 (Mitsumi Electric Co., Ltd.) • IFT YD-1073-1 (Mitsumi Electric Co., Ltd.) • FM-DET 600BEAS-9715Z (Toko Electric Corporation) Pin Function Pin No. Pin Pin voltage Equivalent circuit Pin function 1 FM IF input Vreg Input impedance ri = 330 Ω 2 AM mixer output VCC Connect the mixer coil between this pin and VCC. 3 FM IF input Vreg bypass 4 AM IF input Vreg 5 GND 0V 6 TU-LED, 7 ST-LED, VCC VCC AM - IF output See pin 1 Also used for the multiplex regulator filter Input impedance ri = 2 kΩ Active low Open collector AM stereo IF output (pin 7) This pin must be set up with an influx current under 150µA. 8 9 VCC FM detector VCC Recommended detector coil 600BEAS-9715Z (The Toko Electric Corporation) Continued on next page. No.8271-4/9 LA1837M Continued from preceding page. Pin No. Pin 10 AM narrow band Pin voltage 1.3V Equivalent circuit Pin function Recommended narrow band ceramic filter ceramic filter BFU450C4N (Murata Mfg. Co., Ltd.) connection When the narrow band SD function is not used, bypass this circuit by connecting a 50Ω resistor and a 0.047µF capacitor in series. 11 FM S-meter 0V RL = 8kΩ 0V (AM) The AM SD sensitivity can be adjusted with an external resistor output 12 AM S-meter output, between this pin and ground. AM SD sensitivity adjustment 13 AM/FM IF buffer 0V V13 ≤ 0.5V: Reception state output, 1.4V ≤ V13 ≤ 2.2V: IF buffer output on Output control V13 ≥ 3.5V: IF buffer output and muting on switch (muting switch) 14 15 VCC-1.4 (FM) The IC switches to AM mode when this pin is connected to ground comparator Phase low-pass filter 0V (AM) Resistor value limits: 2.7kΩ (when VCC = 7V) through a resistor. (FM/AM 3.9kΩ (8V) switching) 6.2kΩ (10V) 7.5kΩ (11V) Pilot detector VCC-1.0 5.1kΩ (9V) When a current of over 50µA is sourced by this pin, the IC low-pass filter switches to forced monaural mode. (Forced The VCO is stopped if this pin is connected to ground. monaural) The resistor value limits are the same as for pin 14. (VCO stop) 16 Post amplifier Verg Output impedance ro = 200Ω 17 I/O Verg Pin 16: right output, pin 17: left output 18 Inverting input pins 19 Pin 18: right input, pin 19: left input RNF = 33kΩ 20 Multiplex output 21 3.5V Output impedance ro = 3.3kΩ 3.5V Pin 20: Right channel deemphasis Pin 21: Left channel deemphasis 22 Multiplex input 2.9V Input impedance ri = 20kΩ 23 FM 2.8V (FM) Output impedance ro = 3.0kΩ demodulated 2.8V (AM) The separation can be adjusted with an external capacitor output connected between this pin and ground. The VOsub/VOmain ratio is set to be approximately 0dB. Continued on next page. No.8271-5/9 LA1837M Continued from preceding page. Pin No. 24 Pin Pin voltage Equivalent circuit Pin function AM detector 0V (FM) Output impedance ro = 3.3kΩ The AM frequency characteristics output 0.5V (AM) can be adjusted with an RC circuit connected between pin 22 and ground. 25 AM AGC 0V (FM) Internal load resistance R = 11kΩ 0.5V (AM) 26 AFC Vreg The FM SD bandwidth can be adjusted with an external resistor connected between this pin and pin 28. 27 AM RF input Vreg This pin must be held at the same potential as pin 28 28 REG Vreg Vreg = 3.6V 29 OSC Vreg Connect the oscillator coil between this pin and pin 28. Oscillator buffer 1.6V (FM) The FM SD sensitivity can be adjusted with an external resistor output, FM SD 1.3V (AM) connected between this pin and ground. 30 sensitivity Output impedance ro = 20Ω adjustment No.8271-6/9 LA1837M No.8271-7/9 LA1837M No.8271-8/9 LA1837M Test Circuit ON Semiconductor and the ON logo are registered trademarks of Semiconductor Components Industries, LLC (SCILLC). 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