AN7280S

ICs for FM/AM Tuner AN7280S FM Front-end IC for Car Radio s Overview The AN7280S is an FM front-end IC designed for DTS except RF amp. of car radio. It features built-in local oscillation frequency buffer output, PIN diode driver for antenna damping and SSC (search stop control). Unit : mm 0.4 1 2 3 4 5 6 7 8 9 10 20 19 18 17 16 15 14 13 12 11 1.5±0.2 0.4±0.25 s Features • High sensitivity, high S/N ratio • Good IM characteristics at strong input • Available for two loop AGC (keyed AGC) • Pre IF amp. gain variable • PIN diode driver (ADX) built-in 0.1±0.1 1.27 0.3 5.4±0.3 7.7±0.3 20-Lead SOP Package (SOP020-P-0300B) s Block Diagram GND 20 19 18 17 16 15 14 13 12 11 ADX IF Amp. Mixer VREG Buffer AGC Amp. Buffer SSC Det. OSC 1 2 3 4 5 6 7 8 GND 9 10 VCC 0.15 0.65 12.6±0.3 AN7280S s Absolute Maximum Ratings (Ta=25˚C) Parameter Supply Voltage Supply Current Power Dissipation Operating Ambient Temperature Storage Temperature Symbol VCC ICC PD Topr Tstg Rating 9.2 50 460 –40 ~ + 85 –55 ~ + 150 ICs for FM/AM Tuner Unit V mA mW ˚C ˚C s Recommended Operating Range (Ta=25˚C) Parameter Operating Supply Voltage Range Symbol VCC Range 6.8V ~ 9.2V s Electrical Characteristics (Ta=25˚C) Parameter S/N Ratio Local Oscillation Level IF Output Level AGC Level (L) AGC Level (H) Symbol NOUT VOSC VOUT VAGC (L) VAGC (H) Condition VCC= 8V, Vin=17dBµNo modulation However, S= output at 400Hz, 30%modulation VCC= 8V, fOSC= 108.7MHz Measured by Pin4, No signal input VCC= 8V, Vin= 51dBµ VCC= 8V, Vin= 67dBµ VCC= 8V, Vin= 53dBµ 6 min. 22 219 41 typ. 30 384 58 0.05 6.5 435 82 0.5 max. Unit dB mV mV V V s Characteristics Curve Level · Diagram 50 43.5 (max.) 40 Level (dB) 0 30 20 13.5 AFOUT (dB) 10 0 8.5 –40 24.5 16.0 (min.) –20 Vin (dBµV) VCC=8V fin=98MHz Mod.=22.5kHz fm=1kHz IF : AN7256 400Hz HPF ON 20 15 10 5 0 –5 –10 –15 –80 0 20 40 Vin (dBµV) 60 80 88 90 92 94 96 98 100 102 104 106 108 fin (MHz) Residual Noise Practical Sensitivity (S/N=30dB) Input/Output Characteristics Frequency Change VCC=8V fin=1kHz Mod.=22.5kHz IF : AN7256 Limiting Sensitivity IFT IN Mix. 080 MS3 0.01µF IF–Amp. 330Ω IF OUT –60 ICs for FM/AM Tuner AN7280S AGC ON Level 110 VCC= 8V fin = 18MHz Radj. is Piny external resistance (AGC Start Point Variable) AGC ON Level (dBµV) IF-Amp. Gain Adjustment Input 40 100 IF Amp. 13 f=10.7MHz Output 330Ω Amp. Gain Adjustment with AGC VCC = 8V fin = 98MHz No Adjustment Pin7 = HIGH 110 100 90 Vin (dBµV) Gain (dB) 30 90 80 Radj.= 0Ω 80 Pin9 = High 20 27dB 70 60 70 10 50 0 ∞ 0 Radj.= ∞ 60 Pin9 = Low 50 0 1 1.4 1.8 2.2 in 0 1k 10K 4 (V) 0 1k 10K ∞ Pin13 Adjusting Resistance (Ω) Pin7 Vcont Pin6 Adjusting Resistance (Ω) Supply Voltage Change Supply Voltage Dependence No Input 35 11 10 5 4 Vref 15 10 Itot Vref (V) 3 2 1 0 12 AGC OUT Vt (V) 9 Supply Voltage Dependence No Input 110 100 Vin (dBµV) Local Oscillation Level 30 25 Itot (mA ) 60 AGC ON Level 50 20 5 Vt SSC ON Level (V) 4 3 SSC ON Level 2 1 0 8 7 6 5 4 20 10 0 6 Practical Sensitivity Limiting Sensitivity 7 8 VCC (V) 9 10 5 0 0 2 4 6 VCC (V) 8 10 5 6 7 8 9 10 11 12 VCC (V) Temperature Characteristics 80 70 60 4 Vin (dBµV) 10 IC for IF/DET is normal temperature 8 6 Total Gain Temperature Characteristics Mixer+IF–Amp. VCC= 8V 105 100 95 90 Vin (dBµV) 85 80 75 70 65 60 –40 –20 0 20 40 60 80 100 55 AGC Start Point Temperature Characteristics Pin7=1V Pin6=GND Pin9=OPEN 50 40 30 20 10 AGC ON Level (max. Gain) Total Gain (dB) 2 0 –2 –4 0dB= 43.5dB Pin7=HIGH Pin6=GND Pin9=OPEN Pin7=HIGH Pin6=OPEN Pin9=5V Pin7=HIGH Pin6=OPEN Pin9=OPEN –40 –20 0 20 40 60 80 100 Practical Sensitivity (S/N=30dB) Limiting Sensitivity 0 20 40 60 80 100 –6 –8 –10 0 –60 –40 –20 Ta (˚C) Ta (˚C) Ta (˚C) AN7280S IF Amp. Output Saturation Level Temperature Characteristics 5 VCC=8V 4 IF Amp. Output Saturation Level (dB) 3 2 1 0 –1 –2 –3 –4 –5 –40 –20 0 20 40 60 80 100 0 –40 –20 0 20 40 60 80 100 1 Pino Voltage (V) 3 4 5 SSC Input Pin 9 ICs for FM/AM Tuner SSC ON Level Temperature Characteristics 2 Ta (˚C) Ta (˚C) s Application Circuit VCC 820Ω ANT 82kΩ 0.001µF MA551 18pF KVC–1340 15pF 18pF 3SK1311 22Ω 0.01µF KVC–1340 12pF 100kΩ 100kΩ 330Ω 0.001µF 100kΩ Produced by MATSUSHITA IFT : ZIF–5EF021B 330Ω 470Ω C–F 4pF 0.01µF 1kΩ 0.01µF 0.01µF To IF 12 11 20 100kΩ 19 18 RF IN 17 16 15 14 IF IN 13 GND PIN D AGC Pass Mix Mix Con. OUT OUT E 1 12pF B 2 AGC Gain 2 Loop Pass OSC C OUT AGC Adj IN GND SSC 3 56pF 0.01µF 0.001µF AN7280S 4 5 IF Pass IF Gain Con. OUT Adj VCC 10 0.01µF 6 7 180kΩ 8 9 + – 120kΩ KVC–1340 3pF VT 1µF 0.01µF 56pF 5V 5V 0V Control Voltage At Search At Normal 0V ICs for FM/AM Tuner s Pin Descriptions Pin No. 1 Pin Name OSC Emitter Description Local oscillation transistor emitter pin 2 1 2 OSC Base Local oscillation transistor base pin AN7280S Equivalent Circuit Vref 5V 3 OSC By-pass Vref by-pass pin for mixer,OSC buffer,OSC section + – 3 Vref 4 OSC Buffer Output Pin for output OSC signal to pre-scaler 4 750Ω VCC .70µA 5 Level Detection Output AGC signal output pin for RF-Amp. secondary gate 5 6 AGC– Amp. Gain Adjustment Pin for adjusting AGC Amp. gain by external resistance 6 5.6kΩ 7 Control Signal Input Pin for adjusting AGC-Amp. gain through input of control signal from IF section 1.5kΩ 1.5V 7 8 GND Vref 9 SSC Input Pin for adjusting AGC-Amp. gain through input of control signal from microcomputer 70kΩ 39kΩ 9 10 VCC AN7280S s Pin Descriptions (Cont.) Pin No. Pin Name Description ICs for FM/AM Tuner Equivalent Circuit 11 IF-Amp. IF-Amp. output pin 3kΩ 240Ω 11 ZOUT.300Ω 12 IF-Amp. By-pass IF-Amp. by-pass pin 330Ω 12 14 14 IF-Amp. Input IF-Amp. input pin 13 IF-Amp. Gain Adjustment Pin for adjusting IF-Amp. gain by external resistance 13 340Ω 12kΩ 15 Mix. Output 16 Mixer output pin 15 16 2.2kΩ 17 Mix. By-pass Mixer by-pass pin 17 18 2.2kΩ 18 Mix. Input Mixer input pin VCC 19 ADX Output PIN diode driver output pin Determine maximum current to PIN diode by Pin19 external resistance value. 19 20 GND Oscillator GND ICs for FM/AM Tuner s Operational Description • Loop AGC AN7280S The AN7280S uses 2Loop AGC for AGC circuit. 2Loop AGC controls AGC output by using mixer output (IFT first side) signal and FM–IF control voltage (level meter output), which is a very favorable system for disturbance characteristics, etc. IFT RF–Amp. Mixer IF–Amp. FM–IF To N.C. Control Voltage Output AGC Amp. AGC Det. • AGC start point (Mixer input level at V AGC < 3V) changes in proportion to Pin6 external resistance (following R1) , Pin 7 applied voltage (Determine IF control voltage by R2, R3 resistance division) SSC ON/OFF · Variable width at R 1 28dB (however, V7 ≥3V, V9 = 0V) · Variable width at R7 40dB (however, R1= ∞, V9= 0V) · Variable width at R9 10dB (however, R1= ∞, V7 ≥3V) VREF 3 AGC Output AGC–Adj 5 6 R2 Vcont IN 7 SSC IN 9 about 4.7V VAGC R1 R3 from microcomputer FM–IF Control voltage • SSC Change AGC start point by microcomputer control signal at seek/reception time. Use at SSC ON ········V9 > 3.5V Use at SSC OFF········V9 < 1.5V * SSC is designed as precondition for switching operation at microcomputer control signal.