MGM 3000X Video Modulator for FM/AM-Audio Bipolar IC Features ● ● ● ● ● ● ● ● ● ● ● ● FM- and AM-audio modulator Audio carrier output for suppression of harmonics Sync level clamping of video input signal Controlling of peak white value Continuous adjustment of modulation depth for positive or negative values Symmetrical mixer output with separate ground area Symmetrical oscillator with separate RF-ground Low spurious radiation High stability of the RF-oscillator frequency High stability of the audio oscillator Internal reference voltage 12 V supply voltage P-DSO-20-1 Type Ordering Code Package MGM 3000X Q67000-A5179 P-DSO-20-1 (SMD) MGM 3000X Q67006-A5179 P-DSO-20-1 Tape & Reel (SMD) Functional Description and Application The monolithic integrated circuit MGM 3000X is especially suitable as a modulator for the 48 to 860 MHz frequency range. Video recorders, cable converters, TV-converter networks, demodulators, video generators, video security systems, amateur TV-applications and personal computers. Circuit Description Oscillator The RF-oscillator is available at pins 3 - 7. The oscillator operates as a symmetrical Colpitts circuit. The oscillator chip ground, pin 5, should be connected to ground at the resonance circuit shielding point. An external oscillator can be injected inductively or capacitively via pins 3 and 7. The layout of the PCB should be such as to provide a minimum shielding attenuation between the oscillator pins 3 - 7 and modulator output pins 15 - 17 of approximately 80 dB. Semiconductor Group 1 12.94 MGM 3000X For optimal residual carrier suppression, the symmetrical mixer outputs at pins 15, 17 should be connected to a matched balanced-to-unbalanced broadband transformer, e.g. a Guanella transformer with good phase precision at 0 ° and 180 °. The transmission loss should be less than 3 dB. In addition, an LC-low pass filter combination is required at the output. The cut-off frequency of the low pass filter combination must exceed the maximum operating frequency. Video The video signal with the negative synchronous level is capacitively connected to pin 12. The internal clamping circuit is referenced to the synchronizing level. Should the video signal change by 6 dB, this change will be compensated by the resonance circuit which is set by the peak white value. At pin 13, the current pulses of the peak white detector are filtered through the capacitor which also determines the control time constant. The RF-carrier switches from negative to positive video modulation, when pin 14 is connected to ground. By varying the value of resistance R at pin 14 between ∞ … 0 Ω the modulation depth can be increased from 70 % to 100 % when the modulation is negative and decreased from 100 % to 70 % when the modulation is positive. Audio Via pin 1, the audio signal is capacitively coupled to the AF-input for the FM-modulation of the oscillator. A parallel resonance circuit is connected to the audio carrier oscillator at pins 19, 20. The unloaded Q of the resonant circuit must be Q = 25 and the parallel resistor RT = 6.8 kΩ to ensure a video to audio carrier ratio of 12.5 dB. At the same time, capacitative and/or inductive reactance for the resonance frequency should have a value of XC ≈ XL ≈ 800 Ω. Via pin 18, the audio signal is capacitively coupled to the AF-input for the AM-modulation of the oscillator. This signal is forwarded to a mixer which is influenced by the AMmodulation input of pin 18. The video to audio carrier ratio can be changed by connecting an external voltage to pin 18, which deviates from the internal reference voltage. Through an additional external dc voltage at pin 18, the set AM-modulation index can be changed by overriding the internally adjusted control voltage for a fixed AM-modulation index. At the output of the above described mixer the FM and/or AM modulated audio signal is added to the video signal and mixed with the oscillator signal in the RF-mixer. For optimal suppression of harmonics of the audio carrier an audio filter should be connected between pin 10 and 11. Source The internal reference voltage is available at pin 2 and has to be capactively blocked there. Semiconductor Group 2 MGM 3000X Pin Configuration (top view) Semiconductor Group 3 MGM 3000X Pin Definitions and Functions Pin No. Symbol Function 1 FM-Audio AF-input for FM-modulation 2 VREF Internal reference voltage (7.5 V) 3 OSC-Input 1 Symmetrical oscillator input 4 OSC-Out 1 Symmetrical oscillator output 5 OSC-Ground Oscillator ground 6 OSC-Out 2 Symmetrical oscillator output 7 OSC-Input 2 Symmetrical oscillator input 8 VS Supply voltage (12 V) 9 N.C. Not connected 10 Audio Out 1 Audio output; symmetrical inputs for audio filter 11 Audio Out 2 Audio output; symmetrical inputs for audio filter 12 Video Video input with clamping 13 Video-Cap. Connection for smoothing capacitor for video control loop 14 Modulation Switch-over for positive and negative modulation 15 Output 2 Symmetrical RF-output 16 Ground Ground 17 Output 1 Symmetrical RF-output 18 AM-Audio Video to audio carrier ratio adjustment and AF-input for AM-modulation 19 FM-Audio OSC FM-audio oscillator, symmetrical inputs for tank circuit 20 FM-Audio OSC FM-audio oscillator, symmetrical inputs for tank circuit Semiconductor Group 4 MGM 3000X Block Diagram Semiconductor Group 5 MGM 3000X Absolute Maximum Ratings TA = 0 to 70 °C Parameter Symbol Limit Values min. Unit Remarks typ. max. Supply voltage pin 8 VS − 0.3 14.5 V Current from pin 2 − I2 0 2 mA Voltage at pin 1 Voltage at pin 2 Voltage at pin 12 V1 V2 V10 0 6 0 2 8.5 1.5 V V Vpp Capacitance at pin 2 Capacitance at pin 13 C2 C13 0 0 100 15 nF µF Voltage at pin 14 Voltage at pin 15 Voltage at pin 17 Voltage at pin 18 V14 V15 V17 V18 − 0.3 1.4 13.5 13.5 V2 + 1.5 V V V V V2 V2 V2 − 1.5 V2 = 7-8 V, VS = 10-13.5 V only via C (max.1 µF) VS = 10-13.5 V According to the application circuit, only the provided circuitry can be connected to pins 3, 4, 6, 7, 10, 11, 18 and 20. Junction temperature Tj Storage temperature Tstg Thermal resistance Rth – 40 150 °C 125 °C 80 K/W Operating Range Supply voltage VS 10 13.5 V Video input frequency fVideo 0 6 MHz Audio input frequency fAF 0 20 kHz Output frequency fQ 30 860 MHz depending on the oscillator circuitry at pins 3-7 Ambient temperature TA 0 80 °C Semiconductor Group 6 MGM 3000X Absolute Maximum Ratings (cont’d) TA = 0 to 70 °C Parameter Symbol Limit Values min. Unit Remarks typ. max. Audio oscillator fOSC 4 7 MHz Voltage at pin 2 Voltage at pin 15, 17 V2 V15, 17 7 7.50 V2 VS V V AC/DC Characteristics TA = 25 °C; VS = 12 V Parameter Symbol Limit Values min. typ. max. Unit Test Condition Test Circuit Source Current consumption Current consumption I8 I15 + I17 15 2.0 20 2.6 26 3.4 mA mA I2 = 0 mA 1 Reference voltage V2 7.00 7.25 7.50 V 0 ≤ I2 ≤ 1 mA 1 Oscillator frequency range fOSC 30 860 MHz external circuitry adjusted to frequency Switch-on, warm up drift TC-value of capacitor in osc. circuit is 0; drift is referenced only to selfheating of the component. ∆fOSC Frequency drift as function of VS ∆fOSC – 150 RF-output impedance R15; R17 10 C15; C17 0.5 Oscillator Semiconductor Group t = 0.5-10 s; TA = const. 0 0 – 50 – 500 kHz – 200 – 500 kHz 150 1 2.0 7 Ch 30 Ch 40 1 1 kHz VS = 10-13.5 V TA = const.; Ch 40 1 kΩ parallel equivalent circuit parallel equivalent circuit 1 pF 1 MGM 3000X AC/DC Characteristics (cont’d) TA = 25 °C; VS = 12 V Parameter Symbol Limit Values min. typ. max. Unit Test Condition Test Circuit Ch 60; video 100 % white; without audio- signal 1 RF-output voltage VQ 2.5 4.5 5.5 mVrms RF-output phase a15, 17 140 180 220 deg RF-output voltage changes ∆VQ 0 1.5 dB f = 743.25- 1 dB dB 823.25 MHz ∆f = 80 MHz; Ch 55-65 f = 100-300 MHz f = 48-100 MHz 1 1 ∆VQ ∆VQ 0 0 Intermodulation ratio aIMR 60 Harmonic wave ratio aO 60 1.5 1.5 75 dB fVC + 1.07 MHz fVC + 1.57 MHz fVC + 2.07 MHz 2 dB fVC + 8.8 MHz fVC + 13.29 MHz fVC + 17.72 MHz, 2 without video 13, 14, 15 unmodulated video and audio carrier, measured with the spectrum analyzer as difference between video carrier signal level and sideband signal level; loaded Q factor QL of the audio oscillator resonance circuit adjusted by RP to provide the required video to audio carrier ratio of 12.5 dB; QU = 25. Video to audio carrier ratio aV/A 10 Harmonic wave ratio Harmonic wave ratio aO aO 60 80 Semiconductor Group 12.5 15 8 dB fVC + fAC (5.5 MHz) 1 dB dB fVC + 2fAC (11 MHz) fVC + 3fAC (16.5 MHz) 1 1 MGM 3000X AC/DC Characteristics (cont’d) TA = 25 °C; VS = 12 V Parameter Symbol Limit Values min. All remaining a harmonic waves; multiple of fundamental wave of video carrier, without video signal, measured with spectrum analyzer; fVC = 523.25623.25 MHz; pin 14 open. typ. Unit Test Condition Test Circuit max. 15 dB 1 dB Ch 30 … 40 3 Residual carrier suppression aR 32 Signal-to-noise in video; unmodulated audio carrier aN/V 48 74 dB Ch 60 4 aA/V aA/V 49 48 62 60 dB dB Ch 60; mA = 90 % Ch 60; ± 35 kHz 4 4 Unweighted AM aV/A 48 54 dB 5 Unweighted FM aV/A 48 54 dB Ch 39; test picture FuBK Ch 39; test picture FuBK aN/A aN/A 48 48 54 54 dB dB AM unmodulated FM video carrier 5 5 Video input current at pin 12 – I12 0 1 µA C12 ≤ 100 nF 1 Video input voltage at pin 12 V12 0.7 1.4 Vpp C12 ≤ 100 nF 1 Interference product ratio audio in video AM-modulation FM-modulation of audio carrier 5 Interference level ratio video in audio Signal-to-noise ratio of audio oscillator Video Semiconductor Group 9 MGM 3000X AC/DC Characteristics (cont’d) TA = 25 °C; VS = 12 V Parameter Symbol Limit Values min. Modulation depth typ. Unit Test Condition Test Circuit staircase signal at video input; VVideo = 1 Vpp 6 max. mD/N 70 90 % mD/P 80 98 % ± 2.5 ± 2.0 ± 2.0 % % % ∆VVideo = 1 Vpp ± 3 dB; 6 6 TA = 0-60 °C 6 VS = 10-13.5 V 7 Stability of mod. depth ∆mD Stability of mod. depth ∆mD Stability of mod. depth ∆mD 1 1 1 Differential gain adif 10 % Differential phase Φdif 15 deg Amplitude response of video signal; VVideo = 1 Vpp with additional modulation f = 15 kHz-5 MHz sine signal between black and white. aV 1.5 dB 0 Period of time t required for peak white detector to reach steady state for full modulation depth with 1-white pulse per half frame when control is already in the steady state. 6 50 µs Setting time for video signal change from 0 Vpp to 1.4 Vpp, video blanking signal content is uniform white level. 120 500 µs Semiconductor Group t 10 measured with measurement demodulator, video test signals and vector scope 7 8 C at pin 13 = 10 µF Ileakage ≤ 2 µA 1 1 MGM 3000X AC/DC Characteristics (cont’d) TA = 25 °C; VS = 12 V Parameter Symbol Limit Values Unit Test Condition Test Circuit min. typ. max. t 0.4 2 10 min 1 Audio oscillator frequency range; unloaded Q factor of resonance circuit QU = 25; fresonance = 5.5 MHz. fA/OSC 4 7 MHz 1 Switch-on, warm-up drift of oscillator frequency; TC-value of capacitor in audio oscillator circuit is 0, the drift is only based on self-heating of component. ∆fA/OSC 5 kHz Audio signal frequency devitation ∆fA/OSC Setting time for video blanking signal from 100 % white level to 42 % grey level with subsequent rise in grey level to 71 % of video blanking signal (due to decontrol process). Audio TA = const.; 1 > 5 s after switching on 5 kHz VS = 12 V ± 10 % QU = 25 1 70 % VAF = 90 mVrms 9 0.5 3 % m = 80 %; VAF = 117 mVrms; fAF = 1 kHz 9 50 75 kΩ AM-Audio AM-mod. factor m AM-mod.; total harmonic distortion THDAM Audio preamplifier input impedance Z18 Semiconductor Group 50 25 11 1 MGM 3000X AC/DC Characteristics (cont’d) TA = 25 °C; VS = 12 V Parameter Symbol Limit Values min. typ. Unit Test Condition Test Circuit max. AM-audio modulator input voltage VAF 132 mVrms m = 90 %; fAF = 1 kHz 9 Residual carrier FM; AM-operation ∆f 20 Hz without AM-audio signal QU = 25 1 FM-mod.; total harmonic distortion THDFM 0.6 % V1 = 150 mVrms 9 FM-mod.; static mod. characteristic ∆fA/OSC ± 150 ± 210 ± 270 kHz ∆VAF = V1 – V2 = ± 1 V 1 FM-mod.; dynamic mod. characteristic ∆fA/OSC/ ∆VAF 0.30 FM-Audio 0.25 0.36 Audio preamplifier input impedance (dynamic); FM-operation Z1 0.33 1.5 0.36 kHz/mV BIN 1 0.30 0.44 kHz/mV BIN 2 kHz/mV BIN 3 200 kΩ 1 Overshoot Overshoot Semiconductor Group 1 12 % 1 15-kHz video signal MGM 3000X Test Circuit 1 Test and Measurement Circuit for AM- and FM-Audio Carrier and Negative Video Modulation Semiconductor Group 13 MGM 3000X CC-level lies below the activation point and has been set to provide a ratio of 17 dB with respect to the video carrier. fVC = 623.25 MHz Test Circuit 2 Description of the Measurement Configuration to Measure the Moire Semiconductor Group 14 MGM 3000X Test Circuit 3 Description of the Measurement Configuration to Measure the Residual Carrier Suppression Semiconductor Group 15 MGM 3000X Calibration:AF-signals are switched off, video signal is present at video input, modulation measurement device set at AM is adjusted to video carrier; filter: 300 Hz … 20 kHz; detector: (P + P)/2; Wave analyzer at video signal level (16 kHz) adjusted and resultant level as reference aV defined. 1. Measurement of audio interference product ratio in video while the audio carrier FM modulated: AF-signal is connected to FM-audio input; video signal is present at video input; Modulation measurement device set at AM; filter: 300 Hz … 20 kHz; detector: (P + P)/2; the automatic RF-level position of the measurement device is switched off; wave analyzer at video signal level 1 kHz or 2 kHz or 3 kHz adjusted and resultant level is set to aA. The audio noise ratio in video results from aA/V = aA – aV (dB). 2. Measurement of signal-to-noise ratio in video without FM-modulation of audio carrier: AF-signals are switched off; video signal is switched on; modulation measurement device set at AM; filter: 300 Hz … 3 kHz; detector; RMS × √2; Wave analyzer at video signal level (16 kHz) detuned; read out in dB to reference level of calibration is aN/V; 3. The noise limit of the measurement device is approx. 85 dB. Test Circuit 4 Description of the Measurement Configuration to Measure the Audio and/or Noise in Video during FM- and AM-Modulation of the Audio Carrier Semiconductor Group 16 MGM 3000X Calibration: AF-signal of f = 1 kHz, corresponding with a nominal deviation of 30 kHz, is connected to the audio input, and the demodulated AF-reference level at the audio measurement device is defined as 0 dB. No video signal is present. Measuring: 1. The AF-signal is switched off and the FuBK-video signal is connected to the video input with VVideo = 1 Vpp. The audio level is relation to the AF-reference calibration level is measured as ratio aV/A. 2. AF-and video signals are switched off. The noise ratio in relation to the AF-reference calibration level is measured as signal-to-noise ratio in the audio signal aN/A. Test Circuit 5 Description of the Measurement Configuration to Measure the Video and or Noise in Audio Semiconductor Group 17 MGM 3000X Calibration: A zero reference signal with the TV measuring receiver is given to the video signal. A video signal with VVideo = 1 Vpp is connected to the video input. Measuring: 1. Modulation depth mD/N for negative modulation: pin 14 open, range peak white value-sync level in relation to range zero reference-sync level gives mD/N. 2. Modulation depth mD/P for positive modulation: pin 14 to ground, range peak white value-sync level in relation to range zero reference-peak white value gives mD/P. Test Circuit 6 Description of the Measurement Configuration to Measure the Modulation Depth for Positive and Negative Modulation Semiconductor Group 18 MGM 3000X Test Circuit 7 Description of the Measurement Configuration to Measure the Differential Gain and Phase Semiconductor Group 19 MGM 3000X Test Circuit 8 Description of the Measurement Configuration to Measure the Video Amplitude Response Semiconductor Group 20 MGM 3000X Test Circuit 9 Description of the Measurement Configuration to Measure the Harmonic Distorsion Factor and AM-Input Voltage Semiconductor Group 21 MGM 3000X Diagram Function of Video Signal Connection. a) Demodulated RF-output video signal V15/17rms = f(V12rms); fmod = 16 kHz b) V13 = f(V12rms) Semiconductor Group 22 MGM 3000X GPS05094 Plastic Package, P-DSO-20-1 (SMD) (Plastic Dual Small Outline) Sorts of Packing Package outlines for tubes, trays etc. are contained in our Data Book “Package Information” SMD = Surface Mounted Device Semiconductor Group 23 Dimensions in mm