Motorola MC1374P Datasheet

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The MC1374 includes an FM audio modulator, sound carrier oscillator , RF oscillator, and RF dual input modulator . It is designed to generate a TV signal from audio and video inputs. The MC1374’s wide dynamic range and low distortion audio make it particularly well suited for applications such as video tape recorders, video disc players, TV games and subscription decoders.

• Single Supply, 5.0 V to 12 V

• Channel 3 or 4 Operation

• V ariable Gain RF Modulator

• Wide Dynamic Range

• Low Intermodulation Distortion

• Positive or Negative Sync

• Low Audio Distortion

• Few External Components

Order this document by MC1374/D

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TV MODULATOR CIRCUIT

SEMICONDUCTOR

TECHNICAL DATA

P SUFFIX

PLASTIC PACKAGE

CASE 646

ORDERING INFORMATION

Operating

Device

MC1374P TA = 0° to +70°C Plastic DIP

Temperature Range

Package

0.001

6.8k

3.3k

R1 470

C450C3

120

L1 – 4 Turns #22, 1/4 L2 – 40 Turns, #36, 3/16

0.001

470

Channel 3 4

5–25

C14

0.01

0.001

2.2k

″

Dia.

″

Dia.

S1 R10

10k

D1 MPN3404

Figure 1. Simplified Application

+VCC = 12V

0.001

0.22µH

Ω

MC1374

C11

C16

2.2k

Shaded Parts Optional

C12

R14 56k

R12

180k

R13

30k

C15

0.001

R9 560

R11 220

0.22µH L4

1N914

C10

C13

Pin 1

Output

Video In

Audio In

MOTOROLA ANALOG IC DEVICE DATA

 Motorola, Inc. 1996 Rev 0

MC1374

MAXIMUM RATINGS

Supply Voltage 14 Vdc Operating Ambient Temperature Range 0 to +70 °C Storage Temperature Range –65 to +150 °C Junction Temperature 150 °C Power Dissipation Package

Derate above 25°C

ELECTRICAL CHARACTERISTICS (V

AM OSCILLATOR/MODULATOR

Operating Supply Voltage 5.0 12 12 V Supply Current (Figure 1) – 13 – mA Video Input Dynamic Range (Sync Amplitude) 0.25 1.0 1.0 V Pk RF Output (Pin 9, R7 = 75 Ω, No External Load) – 170 – mV pp Carrier Suppression 36 40 – dB Linearity (75% to 12.5% Carrier, 15 kHz to 3.58 MHz) – – 2.0 % Differential Gain Distortion (IRE Test Signal) 5.0 7.0 10 % Differential Phase Distortion (3.58 MHz IRE Test Signal) – 1.5 2.0 Degrees 920 kHz Beat (3.58 MHz @ 30%, 4.5 MHz @ 25%) – –57 – dB Video Bandwidth (75 Ω Input Source) 30 – – MHz Oscillator Frequency Range – 105 – MHz Internal Resistance across Tank (Pin 6 to Pin 7)

Internal Capacitance across Tank (Pin 6 to Pin 7)

(TA = 25°C, unless otherwise noted.)

Rating

= 12 Vdc, TA = 25°C, fc = 67.25 MHz, Figure 4 circuit, unless otherwise noted.)

Characteristics

Value Unit

1.25

10 mW/°C

Min Typ Max Unit

– –

1.8

4.0

– –

kΩ

ELECTRICAL CHARACTERISTICS (T

Characteristics

FM OSCILLATOR/MODULATOR

Frequency Range of Modulator Frequency Shift versus Temperature (Pin 14 open) Frequency Shift versus VCC (Pin 14 open) Output Amplitude (Pin 3 not loaded) Output Harmonics, Unmodulated

Modulation Sensitivity 1.7 MHz

4.5 MHz

10.7 MHz

Audio Distortion (±25 kHz Deviation, Optimized Bias Pin 14) Audio Distortion (±25 kHz Deviation, Pin 14 self biased) Incidental AM (±25 kHz FM)

Audio Input Resistance (Pin 14 to ground) Audio Input Capacitance (Pin 14 to ground)

Stray Tuning Capacitance (Pin 3 to ground) Effective Oscillator Source Impedance (Pin 3 to load)

= 25°C, VCC = 12 Vdc, 4.5 MHz, Test circuit of Figure 11, unless otherwise noted.)

Min Typ Max Unit

– – – –

– – –

– –

4.5

0.2 –

900

–

0.20

0.24

0.80

0.6

1.4

2.0

6.0

5.0

2.0

0.3

4.0 –

–40

– – –

1.0 – –

– –

MHz

kHz/°C

kHz/V mVpp

MHz/V

kΩ

pF pF

kΩ

MOTOROLA ANALOG IC DEVICE DATA

MC1374

Figure 2. TV Modulator

Bias

Section

R10 R11

Q24

Q23

FM Oscillator/Modulator

Audio In

14 4 3 2 8 9 7 6

R12

6.0k

R13 325

Q25

R14

R15

R1 R2 R3 R4 R5 R6 R7 R8 R9

Sound Carrier

OSC B+

R16

Q1 Q2

Q4 Q5

Q26 Q27 Q8 Q9 Q16 Q17

Sound Carrier

Oscillator

Q12 Q13 Q14 Q15

R17

AM Modulator

Q10 Q11

I = 1.15 mA1I = 1.15 mA

RF Out

Q21

AM Oscillator

RF Tank

Q19 Q20

I = 1.15 mA

Q22

Q18

5 1131211

Gnd Sound CarrierInGain Video In

GENERAL INFORMATION

The MC1374 contains an RF oscillator, RF modulator , and a phase shift type FM modulator, arranged to permit good printed circuit layout of a complete TV modulation system. The RF oscillator is similar to the one used in MC1373, and is coupled internally in the same way . Its frequency is controlled by an external tank on Pins 6 and 7, or by a crystal circuit, and will operate to approximately 105 MHz. The video modulator is a balanced type as used in the well known MC1496. Modulated sound carrier and composite video information can be put in separately on Pins 1 and 11 to minimize unwanted crosstalk. A single resistor on Pins 12 and 13 is selected to set the modulator gain. The RF output at Pin 9 is a current source which drives a load connected from Pin 9 to V

CC.

The FM system was designed specifically for the TV intercarrier function. For circuit economy, one phase shift circuit was built into the ship. Still, it will operate from 1.4 MHz to 14 MHz, low enough to be used in a cordless telephone

base station (1.76 MHz), and high enough to be used as an FM IF test signal source (10.7 MHz). At 4.5 MHz, a deviation of ±25 kHz can be achieved with 0.6% distortion (typical).

In the circuit above, devices Q1 through Q7 are active in the oscillator function. Differential amplifier Q3, Q4, Q5, and Q6 acts as a gain stage, sinking current from input section Q1, Q2 and the phase shift network R17, C1. Input amplifier Q1, Q2 can vary the amount of “in phase” Q4 current to be combined with phase shifter current in load resistor R16. The R16 voltage is applied to emitter follower Q7 which drives an external L–C circuit. Feedback from the center of the L–C circuit back to the base of Q6 closes the loop. As audio input is applied which would offset the stable oscillatory phase, the frequency changes to counteract. The input to Pin 14 can include a dc feedback current for AFC over a limited range.

The modulated FM signal from Pin 3 is coupled to Pin 1 of the RF modulator and is then modulated onto the AM carrier.

MOTOROLA ANALOG IC DEVICE DATA

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