U4468B

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Technical content

Features

 5-V Supply Voltage  Gain-controlled 3-stage Wide-band IF Amplifier  Active Carrier Generation by FPLL Principle (Frequency-Phase-Locked-Loop) for True Quadrature Demodulation  Complete Alignment-free AM Demodulator  Switchable Amplitude Detector for Gain Control, which Operates as a Peak Detector for FM Sound and as a Mean Level Detector for AM Sound

Description

The U4468B is an integrated bipolar circuit for full multistandard sound IF signal pro- cessing in TV/VTR and multimedia applications. It supplies AM signals as well as FM/NICAM sound IF signals and thus allows the design of a universal sound IF mod- ule for various applications. Figure 1. Block Diagram

2 U4468B

4777A–TVVCR–01/04 Circuit Description IF Amplifier and AGC The symmetrical IF input signal from the external SAW filter is fed to the pins 1 and 2. In case of FM/NICAM applications, a SAW filter with double band-pass characteristic is required for the vision and sound carrier. In case of the L-standard, a band-pass filter with the center frequency at the L-sound carrier is used. The amplifier consists of three AC-coupled wide-band IF stages. Each differential ampli- fier stage is gain controlled by the AGC (Aut omatic Gain Control) voltage, available at pin 3. The output signal of the IF amplifier is then applied to the FPLL carrier generation, to the mixer for FM/NICAM signals and to the AM demodulator. The IF-AGC is derived from the average level of the AM carrier (L-standard) or from the peak value of the FM carrier (e.g., B/G standard). It controls the three-stage wide-band amplifier to provide a constant SIF signal to the AM demodulator or to the QSS (quasi- split sound) mixer. Standard Switch If the standard switch (pin 7) is in position “low” (for AM sound), the AGC is operating as an average level detector. In position “open” or “high” (for FM/NICAM sound), the AGC acts as a peak value detector. Internal Voltage Stabilizer The internal band gap reference voltage (4.25 V at pin 4) ensures constant perfor- mance, independent of supply voltage and temperature. FPLL, VCO The FPLL (frequency-phase-locked loop) circuit consists of a frequency detector and a phase detector to generate a control voltage for the VCO tuning. In locked mode, the VCO is controlled by the phase detector while in unlocked mode, the frequency detector is superimposed. The VCO operates with an external resonance circuit (L and C paral- lel) and is controlled by integrated varicaps. A practicable VCO alignment of the external coil is the adjustment of the loop filter volt- age (pin 5) to 2.3 V. At this value, the capture and hold range are centered. AM Demodulator The alignment-free AM demodulator is realized by a synchronous detector. The modu- lated IF signal from the wide-band IF amplifier output is multiplied in phase with the limited SIF signal to remove the AM. Then, the resulting AF signal of the demodulator output is fed to the output amplifier and to the AGC stage. Quasi-Split-Sound (QSS) Mixer The QSS mixer is realized by a multiplier circuit. The IF signal (FM/NICAM) is converted to the intercarrier frequency by means of a quadrature signal from the generated picture carrier provided by the PLL. The intercarrier signal is fed via an output amplifier to pin 12. Mute Switch The AM sound output (pin 6) can be muted by switching the pulling mute switch (pin 10) to “low”.

Figure 2. Pinning DIP16

3 CAGC Capacitor for the AGC time constant

4 CREF Capacitor for the internal reference voltage

5 LF Loop filter

6 VO,FM AF output (AM sound)

7 VSW,AGC Standard switch

10 VSW,MUTE Mute switch

12 VO,FM Intercarrier output (FM sound)

13 GND Ground

14 VS Supply voltage (5 V)

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4777A–TVVCR–01/04 Absolute Maximum Ratings Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress rating only and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. Reference point pin 13, unless otherwise specified. Parameters Pin Symbol Value Unit Supply voltage range 14 V s 4.5 to 9.0 V Supply current 14 I s 55 mA Power dissipation (VS = 9 V) P 500 mW Output currents 6, 12 I out 5m A External voltages 1 - 4, 6, 12 Vext +4.5 V 5, 8, 9 +3.5 V 7, 10 V s V Junction temperature T j +125 °C Operating temperature range T amb 0 to +85 °C Storage temperature T stg -25 to +125 °C Electrostatic handling(1) All V ESD ±300 V Note: 1. Equivalent to discharging a 200-pF capacitor through a 0- /g87 resistor Thermal Resistance Parameters Symbol Value Unit Junction ambient when soldered to PCB R thJA 60 K/W

4777A–TVVCR–01/04

Electrical Characteristics

VS = +5 V, Tamb = +25°C; reference point pin 13, unless otherwise specified. Parameters Test Conditions Symbol Min. Typ. Max. Unit DC Supply (Pin 14) Supply voltage V S 4.5 5.0 9.0 V Supply current V in =10 mV or V3 = 2 V I S 40 mA IF Input (Pins 1, 2) Minimum IF input signal Output signal: -3 dB v in 50 µV rms Maximum IF input signal Output signal: +1 dB v in 70 100 mV rms Input impedance (1) Rin 1.2 k /g87 Input capacitance (1) Cin 2p F SIF-AGC (Pin 3) IF gain control range G v 60 65 dB AGC capacitor C AGC 4.7 µF FPLL and VCO (Pins 5, 8, and 9) Maximum oscillator frequency For carrier generation f VCO 70 MHz Vision carrier capture range fVCO = 38.9 MHz CVCO = 6.2 pF /g68fcap ±1.5 ±2 MHz Oscillator drift (free running) as function of temperature /g68Tamb = 55/g176C, fVCO = 38.9 MHz CVCO = 6.2 pF(2) Standard Switch (Pin 7) Switching voltage for mode 1: FM/NICAM sound Peak value control(3) Vsw1 2.0 V S V Switching voltage for mode 2: AM sound Average level control V sw2 01 . 5 V Switching current I sw ±100 µA AM Mute Switch (Pin 10) Switching voltage AM output active V mute1 open Switching voltage AM output switched off V mute2 01 . 5 V Switching current I mute -100 µA Intercarrier Output (Pin 12)(4) DC output voltage V DC 2V Output resistance (1) Rout 200 /g87 Intercarrier output signal vin = 10 mV

5.5 MHz output signal Vout 100 150 mV rms

Intercarrier bandwidth -1 dB -3 dB B TBD TBD MHz MHz Notes: 1. This parameter is given as an application information and is not tested during production. 2. The oscillator drift is related to the picture carrier frequency, with an external temperature-compensated LC circuit. 3. Without external control voltage (pin 7 open), the IC automatically operates in mode 1. 4. Picture carrier PC = 38.9 MHz; sound carrier SC 1 = 33.4 MHz, SC2 = 33.16 MHz; PC/SC1 =13 dB; PC/SC2 = 20 dB; PC unmodulated (equivalent to sync peak level). 5. Sound carrier SC = 32.4 MHz, modulated with f mod = 1 kHz, m = 54%; vin = 10 mV .

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4777A–TVVCR–01/04 Weighted signal-to-noise ratio (CCIR 468) B/G mod. VIF signal: vin =10 mV FM deviation = ±27 kHz fmod = 1 kHz T ested with U2860B Black screen: channel 1/2 Color bar: channel 1/2 dB dB Ripple rejection T ested from pin 14 to 12 (1) RR 35 dB Allowable AC output peak current I AC ±0.7 mA Allowable DC output current I DC -2 mA AF Output - AM (Pin 6) DC output voltage V DC 2.2 V Output resistance (1) Rout 150 /g87 AF output signal m = 54% (5) voAF 500 mV rms AF bandwidth -3 dB (5) BT B D k H z Total harmonic distortion m = 54% fmod = 1 kHz, 12.5 kHz THD 1 2 % Weighted signal-to-noise ratio (CCIR 468) Reference: m = 54%(5) fmod = 1 kHz S/N 56 dB Ripple rejection T ested from pin 14 to 6 (1) RR 28 dB Allowable AC output peak current I AC ±0.3 mA Allowable DC output current I DC -1 mA Electrical Characteristics (Continued) VS = +5 V, Tamb = +25°C; reference point pin 13, unless otherwise specified. Parameters Test Conditions Symbol Min. Typ. Max. Unit Notes: 1. This parameter is given as an application information and is not tested during production. 2. The oscillator drift is related to the picture carrier frequency, with an external temperature-compensated LC circuit. 3. Without external control voltage (pin 7 open), the IC automatically operates in mode 1. 4. Picture carrier PC = 38.9 MHz; sound carrier SC 1 = 33.4 MHz, SC2 = 33.16 MHz; PC/SC1 =13 dB; PC/SC2 = 20 dB; PC unmodulated (equivalent to sync peak level). 5. Sound carrier SC = 32.4 MHz, modulated with f mod = 1 kHz, m = 54%; vin = 10 mV .

Figure 3. Test Circuit

32.4 MHz

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Figure 4. Sound IF Inputs (Pins 1 and 2) Figure 5. AGC Time Constant (Pin 3) Figure 6. Internal Reference Voltage (Pin 4) Figure 7. Loop Filter (Pin 5)

Figure 8. AM Output (Pin 6) Figure 9. AGC Switch (Pin 7) Figure 10. VCO (Pins 8 and 9) Figure 11. Mute Switch (Pin 10)

2.6 V10

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4777A–TVVCR–01/04 Figure 12. Intercarrier Output (Pin 12)

Package Information

1.4 mA IDC 120 Ω

Ordering Information

Extended Type Number Package Remarks U4468B DIP16 – Dimensions in mm 0.5 min 1.64 1.44 technical drawings according to DIN specifications 20.0 max 4.8 max 3.3 7.82 7.42 6.4 max 0.39 max 9.75 8.150.58 0.48 2.54 17.78Alternative 16 9

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