mc1377.pdf

DeviceOperating

Temperature Range Package

SEMICONDUCTORTECHNICAL DATA

COLOR TELEVISIONRGB to PAL/NTSC ENCODER

ORDERING INFORMATION

MC1377DWMC1377P

TA = 0 to +70CSO20L

Plastic DIP

Order this document by MC1377/D

P SUFFIXPLASTIC PACKAGE

CASE 738

DW SUFFIXPLASTIC PACKAGE

CASE 751D(SO20L)

201

201

1MOTOROLA ANALOG IC DEVICE DATA

The MC1377 will generate a composite video from baseband red, green,blue, and sync inputs. On board features include: a color subcarrieroscillator; voltage controlled 90 phase shifter; two double sidebandsuppressed carrier (DSBSC) chroma modulators; and RGB input matriceswith blanking level clamps. Such features permit system design with fewexternal components and accordingly, system performance comparable tostudio equipment with external components common in receiver systems. Selfcontained or Externally Driven Reference Oscillator Chroma Axes, Nominally 90 (5), are Optionally Trimable PAL/NTSC Compatible Internal 8.2 V Regulator

Figure 1. Representative Block Diagram

Oscout

Oscin

NTSC/PALSelect

Gnd

18

17

20

15

QuadDecoup VCC VB

19 14 16

13

10

11

12

9

7

Chroma Out

Chroma In

BY Clamp

RY Clamp

CompositeVideo OutputVideo Clamp

1 2 3 4 5 6 8Trise Composite

Sync InputR G B

Inputs

Yout Yin

OscillatorBuffer

VoltageControlled

908.2V

RegulatorPAL

Switch0/180

ChromaAmp

BYClamp

RYClamp

Output Amp/Clamp

Color Difference andLuminance Matrix

DualComparator

LatchingRamp

Generator

PAL/NTSCControl

BurstPulseDriver

90 0H/2RY BY

RY BY

Y

Motorola, Inc. 1995

MC1377

2 MOTOROLA ANALOG IC DEVICE DATA

MAXIMUM OPERATING CONDITIONSRating Symbol Value Unit

Supply Voltage VCC 15 Vdc

Storage Temperature Tstg 65 to +150 C

Power Dissipation PackageDerate above 25C

PD 1.2510

WmW/C

Operating Temperature TA 0 to +70 C

RECOMMENDED OPERATING CONDITIONSCharacteristics Min Typ Max Unit

Supply Voltage 10 12 14 Vdc

IB Current (Pin 16) 0 10 mASync, Blanking Level (DC level between pulses, see Figure 9e)Sync Tip Level (see Figure 9e)Sync Pulse Width (see Figure 9e)

1.70.52.5

0

8.20.95.2

Vdc

s

R, G, B Input (Amplitude)R, G, B Peak Levels for DC Coupled Inputs, with Respect to Ground

2.21.0

4.4VppV

Chrominance Bandwidth (Noncomb Filtered Applications), (6 dB) 0.5 1.5 2.0 MHzExt. Subscarrier Input (to Pin 17) if OnChip Oscillator is not used. 0.5 0.7 1.0 Vpp

ELECTRICAL CHARACTERISTICS (VCC = 12 Vdc, TA = 25C, circuit of Figure 7, unless otherwise noted.)Characteristics Pins Symbol Min Typ Max Unit

SUPPLY CURRENTSupply Current into VCC, No Load, on Pin 9. VCC = 10 VCircuit Figure 7 VCC = 11 V

VCC = 12 VVCC = 13 VVCC = 14 V

14 ICC

20

3334353637

40

mA

VOLTAGE REGULATORVB Voltage (IB = 10 mA, VCC = 12 V, Figure 7)

Load Regulation (0 < IB 10 mA, VCC = 12 V)Line Regulation (IB = 0 mA, 10 V < VCC < 14 V)

16 VBRegloadRegline

7.720

8.21204.5

8.7+30

VdcmV

mV/V

OSCILLATOR AND MODULATIONOscillator Amplitude with 3.58 MHz/4.43 MHz crystal 17 Osc 0.6 VppSubcarrier Input: Resistance at 3.58 MHzSubcarrier Input: Resistance at 4.43 MHz

17 Rosc

5.04.0

k

Capacitance Cosc 2.0 pF

Modulation Angle (RY) to (BY)Angle Adjustment (RY)DC Bias Voltage

1919

mmV19

50.256.4

DegDeg/A

Vdc

CHROMINANCE AND LUMINANCEChroma Input DC LevelChroma Input Level for 100% Saturation

10 Vin

4.00.7

VdcVpp

Chroma Input: ResistanceChroma Input: Capacitance

RinCin

102.0

kpF

Chroma DC Output LevelChroma Output Level at 100% Saturation

13 Vout 8.9

101.0

10.9

VdcVpp

Chroma Output Resistance Rout 50

Luminance Bandwidth (3.0 dB), Less Delay Line 9 BWLuma 8.0 MHz

MC1377


ELECTRICAL CHARACTERISTICS (VCC = 12 Vdc, TA = 25C, circuit of Figure 7, unless otherwise noted.)Characteristics Pins Symbol Min Typ Max Unit

VIDEO INPUTR, G, B Input DC Levels 3, 4, 5 RGB 2.8 3.3 3.8 Vdc

R, G, B Input for 100% Color Saturation 1.0 VppR, G, B Input: ResistanceR, G, B Input: Capacitance

RRGBCRGB

8.0

102.0

17

kpF

Sync Input Resistance (1.7 V < Input < 8.2) 2 Sync 10 kCOMPOSITE VIDEO OUTPUT

Composite Output,100% Saturation(see Figure 8d)

SyncLuminanceChromaBurst

9 CVout

0.61.41.70.6

Vpp

Output Impedance (Note 1) Rvideo 50 Subcarrier Leakage in Output (Note 2) Vlk 20 mVpp

NOTES: 1. Output Impedance can be reduced to less than 10 by using a 150 output load from Pin 9 to ground. Power supply current willincrease to about 60 mA.

2. Subcarrier leakage can be reduced to less than 10 mV with optional circuitry (see Figure 12).

PIN FUNCTION DESCRIPTIONSSymbol Pin Description

tr 1 External components at this pin set the rise time of the internal ramp function generator (see Figure 10).Sync 2 Composite sync input. Presents 10 k resistance to input.

R 3 Red signal input. Presents 10 k impedance to input. 1.0 Vpp required for 100% saturation.

G 4 Green signal input. Presents 10 k impedance to input. 1.0 Vpp required for 100% saturation.B 5 Blue signal Input. Presents 10 k impedance to input. 1.0 Vpp required for 100% saturation.

Yout 6 Luma (Y) output. Allows external setting of luma delay time.Vclamp 7 Video Clamp pin. Typical connection is a 0.01 F capacitor to ground.

Yin 8 Luma (Y) input. Presents 10 k input impedance.CVout 9 Composite Video output. 50 output impedance.

ChromaIn 10 Chroma input. Presents 10 k input impedance.

BYclamp 11 BY clamp. Clamps BY during blanking with a 0.1 F capacitor to ground.Also used with RY clamp to null residual color subcarrier in output.

RYclamp 12 RY clamp. Clamps RY during blanking with a 0.1 F capacitor to ground.Also used with BY clamp to null residual color subcarrier in output.

ChromaOut 13 Chroma output. 50 output impedance.

VCC 14 Power supply pin for the IC; +12, 2.0 V, required at 35 mA (typical).Gnd 15 Ground pin.

VB 16 8.2 V reference from an internal regulator capable of delivering 10 mA to external circuitry.

Oscin 17 Oscillator input. A transistor base presents 5.0 k to an external subcarrier input, or is available forconstructing a Colpitts oscillator (see Figure 4).

Oscout 18 Oscillator output. The emitter of the transistor, with base access at Pin 17, is accessible for completing theColpitts oscillator. See Figure 4.

m 19 Quad decoupler. With external circuitry, RY to BY relative angle errors can be corrected. Typically,requires a 0.01 F capacitor to ground.

NTSC/PALSelect

20 NTSC/PAL switch. When grounded, the MC1377 is in the NTSC mode; if unconnected, in the PAL mode.

MC1377


FUNCTIONAL DESCRIPTIONFigure 2. Power Supply and VB

0.1 VCC = +12V

16 14

15

32mA

8.2VRegulator

9

100

Figure 3. RGB Input Circuitry

13 17 18 19

ChromaOut Oscillator

QuadDecoup

Amp/Buffer

PAL

Switch0/180

NTSC

PAL

PAL/NTSCControl

BurstFlag

NTSC PAL

BY RY

BY RY

+90

R

Figure 4. Chroma Section

RY

15F3

18k

BY Y

RGB Matrix

18k 18k

15F4

G

15F5

B

6

Y

27k 27k 27k

Power Supply and VB (8.2 V Regulator)The MC1377 pin for power supply connection is Pin 14.

From the supply voltage applied to this pin, the IC biasesinternal output stages and is used to power the 8.2 V internalregulator (VB at Pin 16) which biases the majority of internalcircuitry. The regulator will provide a nominal 8.2 V and iscapable of 10 mA before degradation of performance. Anequivalent circuit of the supply and regulator is shown inFigure 2.

R, G, B InputsThe RGB inputs are internally biased to 3.3 V and provide

10 k of input impedance. Figure 3 shows representativeinput circuitry at Pins 3, 4, and 5.

The input coupling capacitors of 15 F are used to preventtilt during the 50/60 Hz vertical period. However, if it is desiredto avoid the use of the capacitors, then inputs to Pins 3, 4,and 5 can be dc coupled provided that the signal levels arealways between 2.2 V and 4.4 V.

After input, the separate RGB information is introduced tothe matrix circuitry which outputs the RY, BY, and Ysignals. The Y information is routed out at Pin 6 to anexternal delay line (typically 400 ns).DSBSC Modulators and 3.58 MHz Oscillator

The RY and BY outputs (see (BY)/(RY) Axes versusI/Q Axes, Figure 22) from the matrix circuitry are amplitudemodulated onto the 3.58/4.43 MHz subcarrier. These signalsare added and color burst is included to produce compositechroma available at Pin 13. These functions plus others,depending on whether NTSC or PAL operation is chosen, areperformed in the chroma section. Figure 4 shows a blockdiagram of the chroma section.

The MC1377 has two double balanced mixers, andregardless of which mode is chosen (NTSC or PAL), themixers always perform the same operation. The BY mixermodulates the color subcarrier directly, the RY mixerreceives a 90 phase shifted color subcarrier before beingmodulated by the RY baseband information. Additionaloperations are then performed on these two signals to makethem NTSC or PAL compatible.

In the NTSC mode, the NTSC/PAL control circuitry allowsan inverted burst of 3.58 MHz to be added only to the BYsignal. A gating pulse or burst flag from the timing sectionpermits color burst to be added to the BY signal. This colorburst is 180 from the BY signal and 90 away from the RYsignal (see Figure 22) and permits decoding of the colorinformation. These signals are then added and amplifiedbefore being output, at Pin 13, to be bandpassed and thenreintroduced to the IC at Pin 10.

In the PAL mode, NTSC/PAL control circuitry allows aninverted 4.43 MHz burst to be added to both RY and BYequally to produce the characteristic PAL 225/135 burstphase. Also, the RY information is switched alternately from180 to 0 of its original position and added to the BYinformation to be amplified and output.

MC1377


Timing CircuitryThe composite sync input at Pin 2 performs three

important functions: it provides the timing (but not theamplitude) for the sync in the final output; it drives the blacklevel clamps in the modulators and output amplifier; and ittriggers the ramp generator at Pin 1, which produces burstenvelope and PAL switching. A representative block diagramof the timing circuitry is shown in Figure 5.

In order to produce a color burst, a burst envelope must begenerated which gates a color subcarrier into the RY andBY modulators. This is done with the ramp generator atPin 1.

The ramp generator at Pin 1 is an RC type in which thepin is held low until the arrival of the leading edge of sync. Therising ramp function, with time constant RC, passes throughtwo level sensors the first one starts the gating pulse andthe second stops it (see Figure 10). Since the early part ofthe exponential is used, the timing provided is relativelyaccurate from chiptochip and assemblytoassembly.Fixed components are usually adequate. The rampcontinues to rise for more than half of the line interval, therebyinhibiting burst generation on half interval pulses on verticalfront and back porches. The ramp method will produce burston the vertical front and back porches at full line intervals.

RY, BY Clamps and Output Clamp/AmplifierThe sync signal, shown in the block diagram of Figure 6,

drives the RY and BY clamps which clamp the RY andBY signals to reference black during the blanking periods.The output amplifier/clamp provides this same function pluscombines and amplifies the chroma and luma componentsfor composite video output.

Application CircuitFigure 7 illustrates the block diagram of the MC1377 and

the external circuitry required for typical operation.

11

SyncInput

Figure 5. Timing Circuitry

Figure 6. RY, BY and Output Amplifier Clamps

PAL/NTSC

H/2

Line Drive

10k LatchingRamp

GeneratorDual

Comparator

Burst Flag

BurstPulseDriver

PAL/NTSCControl20

2

1

BY

RY

Sync

BYClamp

RYClamp

OutputAmp/Clamp

Chroma10

12

9

7

8Y

CompositeVideo

VB

R

C

0.1

0.1

0.01

Figure 7. Block Diagram and Application Circuit

RY BY

Osc/Buffer

VoltageControlled

908.2V

RegulatorPAL

Switch0/180

ChromaAmp

BYClamp

RYClamp

Output Amp/Clamp

Color Difference andLuminance Matrix

DualComparator

LatchingRampGen

PAL/NTSC

Control

BurstPulseDriver

0.0119

VCC16

VB 0.1 TOKO 166NNF10264AG

13 220

100/62*

0.1

3.3k47/33*

10

9

7 0.01

12

0.1

0.1

1000

3.58/4.43*MHz

220

220

5.0 to25pF

20

15

1 2 3 4 5 6 856k0.001

mica CompositeSyncInput

14

11

CompositeVideo Output

1.0k

400nsY Delay

1.0k

+ + +

15F 15F 15FVB

R G B

R, G, B Inputs

H/2 90 0

NTSC/PAL Select

17

18

* Refers to the choice NTSC/PAL* (3.58 MHz/4.43 MHz).

RY BY

YY

MC1377


10kR29

R21220

R16115k

R12727k

R12918k

R1262.7k

R1233.9k

T111

T23

22kR28

R42.0k

+12V

+8.2V

Gnd

PAL/NTSC

Comp Sync

TRISE

RIN

GIN

BIN

R6A 5.1k

Z1

R21.2k

R2A1.0k

T1R36.8k

R1322k

R1122k

R1210k

R1422k

R22270

R922k

560R25

560R26

T22

T19 T20R231.5kR241.5k

R18220

R20220

T17T15

T16

T24 T25 T26 T27

T10 T13R161.0k

R171.0k

T9

T8T7

R8220

R9220

R5470

T5T4

+ C1

5pFR6

5.1k

R105.0k

R15

T2 T3

R74.0k

+C2

18pF

T11 T12 T285.0kR30

R162

R7122k

R69R7010k

R7222k

R7322k

R7410k

R7510k

T79

T68 T69

R7715k

R7615k

R80A4.0k

R8122k

T71

T73 T74

R8310k

R791.0k

R7815k

Z2T75

R8610k

T76

R8713.8k

R8830.4k

T77

R9518k

T82T81

R942.2k

R932.2k

R922.2k

R9110k

T78 T79T80

R8510k

T72

R8222k

R10022k

T91BT91A

R9622k

R10110k

R9722k

R1021.0k

T90

R9910k

R9822k

T92 T93 T94

R16022k

R1042.0k

R10415k

R1082.7k

R1644.7k

T102 T103 T104

T101T100T99T98

R107820

T95

R1057.5k

R1101.0k

T105

R1114.7k

T107

R11236k

R11327k

R118

R11710k

R12027k

T110T109

T108

R11518k

R1195.3k

R1163.9k

R12218k

T96

R1069.1k R1

09

22k

T206

T97

191817

14

16

15

20

2

1

3

4

5

Osc In Osc Out QuadDecoup

10k

R12127k

22k

R90

R80 B6.0k

T18

T6T14

1.5k

220

R27220

22k

10k

MC1377


R315.1k

R315.1k

T30

R351.0k

R361.0k

R662.4k

R5112k

R67220

T54

R683.0k

R55220

R54220

T50 T51 T52 T53

T57T56

R65220

BY Clamp

T58

R58300

R6310k

R58300

R604.7k

T59

T66

R44A22k

R5210k

R4910k

R45300

R4422k

R4310k

R3810k

R474.7k

T45 T46

T62

T43 T44

R402.0k

R412.0K

T41T40

R471.0k

R461.0k

R39500T39

T47

T63

T64 T65

R622.0k

R612.0k

R561.0kT55

R53500T49

T33 T34T32T31

R37220

T35 T36 T37 T38

T4227kR34

22kR33

10kR29

R21220

R27220

R135220

R1364.7k

R134220

R133220

R1371.5k

R13940k

T118T120

R156220

T117

470R140

470R141

4.7kR138

22kR155

20kR144

R15722k

R14727k

R154100

R153220

T128 Composite Video Out

Video Clamp

Chroma In

RY Clamp

Chroma Out

Y In

Y Out

R1519.1k

R14910k

15kR152

R1504.7k

T126

15kR148

10kR142

R14322k

R1453.3k T123 T124

T125T122

T121

T119

T116

T114

R12412.5 k

R1321.85k

R16310k

R12512.5k

R13114k

R1303.9k

R15910k

R12727k

T113T112

T127

R12918k

R1262.7k

R1233.9k

T1

T23

T48

R50220

R43A10k

T60 T61

22kR28

T285.0kR30

T110

13

11

12

10

9

7

8

6

T115

R128220

R15810k

R48500 R57

1.0k

R64500PA

L F/F

RY

BY

Burst

Flag

Burst

Flag

PAL F

/F

Figure 8. Internal Schematic

MC1377


APPLICATION INFORMATIONFigure 8. Signal Voltages

(Circuit Values of Figure 7)4.4V

Limitsfor DCCoupledInputs

(a)

(b)

(c)

(d)

(e)

(f)

(g)

(h)

(i)

1.0Vpp

1.0Vpp

1.0Vpp

2.2V

5.0

4.0

3.0

8.2 Max1.7 Min

0.9 Max

00.5 Min

10.5

10.0

9.5

4.35

4.0

3.65

5.2

4.3

2.6

2.1

LuminanceInput(Pin 8)

LuminanceOutput(Pin 6)

ChromaInput(Pin 10)

ChromaOutput(Pin 13)

SyncInput(Pin 2)

CompositeOutput(Pin 9)

100%BlueInput(Pin 5)

100%RedInput(Pin 3)

100%GreenInput(Pin 4)

R, G, B Input LevelsThe signal levels into Pins 3, 4, 5 should be 1.0 Vpp for fully

saturated, standard composite video output levels as shownin Figure 9(d). The inputs require 1.0 Vpp since the internallygenerated sync pulse and color burst are at fixed andpredetermined amplitudes.

Further, it is essential that the portion of each input whichoccurs during the sync interval represent black for that inputsince that level will be clamped to reference black in the colormodulators and output stage. This implies that a refinement,such as a difference between black and blanking levels, mustbe incorporated in the RGB input signals.

If Y, RY, BY and burst flag components are available andthe MC1377 is operating in NTSC, inputs may be as follows:the Y component can be coupled through a 15 pF capacitorto Pins 3, 4 and 5 tied together; the ([RY]) component canbe coupled to Pin 12 through a 0.1 F capacitor, and the([BY]) and burst flag components can be coupled to Pin 11in a similar manner.

Sync InputAs shown in Figure 9(e), the sync input amplitude can be

varied over a wide latitude, but will require bias pullup frommost sync sources. The important requirements are:

1)The voltage level between sync pulses must be between1.7 V and 8.2 V, see Figure 9(e).

2)The voltage level for the sync tips must be between+0.9 V and 0.5 V, to prevent substrate leakage in the IC,see Figure 9(e).

3)The width of the sync pulse should be no longer than5.2 s and no shorter than 2.5 s.

For PAL operation, correctly serrated vertical sync isnecessary to properly trigger the PAL divider. In NTSC mode,simplified block vertical sync can be used but the loss ofproper horizontal timing may cause top hook or flagwaving in some monitors. An interesting note is thatcomposite video can be used directly as a sync signal,provided that it meets the sync input criteria.

Latching Ramp (Burst Flag) GeneratorThe recommended application is to connect a close

tolerance (5%) 0.001 F capacitor from Pin 1 to ground and aresistor of 51 k or 56 k from Pin 1 to VB (Pin 16). This willproduce a burst pulse of 2.5 s to 3.5 s in duration, asshown in Figure 10. As the ramp on Pin 1 rises toward thecharging voltage of 8.2 V, it passes first through a burst startthreshold at 1.0 V, then a stop threshold at 1.3 V, and finallya ramp reset threshold at 5.0 V. If the resistor is reduced to43 k, the ramp will rise more quickly, producing a narrowerand earlier burst pulse (starting approx. 0.4 s after sync andabout 0.6 s wide). The burst will be wider and later if theresistor is raised to 62 k, but more importantly, the 5.0 Vreset point may not be reached in one full line interval,resulting in loss of alternate burst pulses.

As mentioned earlier, the ramp method does produceburst at full line intervals on the vertical porches. If this is notdesired, and the MC1377 is operating in the NTSC mode,burst flag may be applied to Pin 1 provided that the tip of thepulse is between 1.0 Vdc and 1.3 Vdc. In PAL mode thismethod is not suitable, since the ramp isnt available to drivethe PAL flipflop. Another means of inhibiting the burst pulseis to set Pin 1 either above 1.3 Vdc or below 1.0 Vdc for theduration that burst is not desired.

MC1377


Color Reference Oscillator/BufferAs stated earlier in the general description, there is an

onboard common collector Colpitts color referenceoscillator with the transistor base at Pin 17 and the emitter atPin 18. When used with a common lowcost TV crystal andcapacitive divider, about 0.6 Vpp will be developed at Pin 17.The frequency adjustment can be done with a series 30 pFtrimmer capacitor over a total range of about 1.0 kHz.Oscillator frequency should be adjusted for each unit,keeping in mind that most monitors and receivers can pull in1200 Hz.

If an external color reference is to be used exclusively, itmust be continuous. The components on Pins 17 and 18 canbe removed, and the external source capacitively coupledinto Pin 17. The input at Pin 17 should be a sine wave withamplitude between 0.5 Vpp and 1.0 Vpp.

Also, it is possible to do both; i.e., let the oscillator free runon its own crystal and override with an external source. An

extra coupling capacitor of 50 pF from the external source toPin 17 was adequate with the experimentation attempted.

Voltage Controlled 90The oscillator drives the (BY) modulator and a voltage

controlled phase shifter which produces an oscillator phaseof 90 5 at the (RY) modulator. In most situations, theresult of an error of 5 is very subtle to all but the most experteye. However, if it is necessary to adjust the angle to betteraccuracy, the circuit shown in Figure 11 can be used.

Pulling Pin 19 up will increase the (RY) to (BY) angle byabout 0.25/A. Pulling Pin 19 down reduces the angle by thesame sensitivity. The nominal Pin 19 voltage is about 6.3 V,so even though it is unregulated, the 12 V supply is best forgood control. For effective adjustment, the simplest approachis to apply RGB color bar inputs and use a vectorscope. Asimple bar generator giving R, G, and B outputs is shown inFigure 26.

Figure 9. Ramp/Burst Gate Generator

Pin 1

Ram

p Volt

age

(Vdc)

1.3

5.0

0

1.0

50 63.58.50 5.5

Burst Stop

Time (s)

Burst Start

Sync(Pin 2)

Residual Feedthrough ComponentsAs shown in Figure 9(d), the composite output at Pin 9

for fully saturated color bars is about 2.6 Vpp, output with fullchroma on the largest bars (cyan and red) being 1.7 Vpp.The typical device, due to imperfections in gain, matrixing,and modulator balance, will exhibit about 20 mVpp residualcolor subcarrier in both white and black. Both residuals canbe reduced to less than 10 mVpp for the more exactingapplications.

The subcarrier feedthrough in black is due primarily toimbalance in the modulators and can be nulled by sinking orsourcing small currents into clamp Pins 11 and 12 as shownin Figure 12. The nominal voltage on these pins is about4.0 Vdc, so the 8.2 V regulator is capable of supplying a pullup source. Pulling Pin 11 down is in the 0 direction, pulling itup is towards 180. Pulling Pin 12 down is in the 90 direction,pulling it up is towards 270. Any direction of correction maybe required from part to part.

White carrier imbalance at the output can only becorrected by juggling the relative levels of R, G, and B inputs

for perfect balance. Standard devices are tested to be within5% of balance at full saturation. Black balance should beadjusted first, because it affects all levels of gray scaleequally. There is also usually some residual baseband videoat the chroma output (Pin 13), which is most easily observedby disabling the color oscillator. Typical devices show 0.4 Vppof residual luminance for saturated color bar inputs. This isnot a major problem since Pin 13 is always coupled to Pin 10through a bandpass or a high pass filter, but it serves as awarning to pay proper attention to the coupling network.

Figure 10. Adjusting Modulator Angle

19

0.01F

220k

12Vdc

10k

MC1377


Figure 11. Nulling Residual Color in Black

Figure 12. Delay of Chroma Information

12

11

470k

470k

VB

VB

10k

10k

Luminance

Chroma

The Chroma Coupling CircuitsWith the exception of SVHS equipped monitors and

receivers, it is generally true that most monitors and receivershave color IF 6.0 dB bandwidths limited to approximately0.5 MHz. It is therefore recommended that the encodercircuit should also limit the chroma bandwidth toapproximately 0.5 MHz through insertion of a bandpasscircuit between Pin 13 and Pin 10. However, if SVHSoperation is desired, a coupling circuit which outputs thecomposite chroma directly for connection to a SVHSterminal is given in the SVHS application (see Figure 19).

For proper color level in the video output, a 0.5 MHzbandwidth and a midband insertion loss of 3.0 dB is desired.The bandpass circuit shown in Figure 7, using the TOKOfixed tuned transformer, couples Pin 10 to Pin 13 and givesthis result. However, this circuit introduces about 350 ns ofdelay to the chroma information (see Figure 13). This must beaccounted for in the luminance path.

A 350 ns delay results in a visible displacement of the colorand black and white information on the final display. Thesolution is to place a delay line in the luminance path fromPins 6 to 8, to realign the two components. A normal TVreceiver delay line can be used. These delay lines are usuallyof 1.0 k to 1.5 k characteristic impedance, and theresistors at Pins 6 and 8 should be selected accordingly. Avery compact, lumped constant delay line is available fromTDK (see Figure 25 for specifications). Some types of delaylines have very low impedances (approx. 100 ) and shouldnot be used, due to drive and power dissipationrequirements.

In the event of very low resolution RGB, the transformerand the delay line may be omitted from the circuit. Very lowresolution for the MC1377 can be considered RGBinformation of less than 1.5 MHz. However, in this situation, abandwidth reduction scheme is still recommended due to theresponse of most receivers.

Figure 14(a) shows the output of the MC1377 with lowresolution RGB inputs. If no bandwidth reduction is employedthen a monitor or receiver with frequency response shown inFigure 14(b), which is fairly typical of noncomb filteredmonitors and receivers, will detect an incorrect lumasideband at X. This will result in crosstalk in the form ofchroma information in the luma channel. To avoid thissituation, a simpler bandpass circuit as shown in Figure15(a), can be used.

Figure 13. MC1377 Output withLow Resolution RGB Inputs

(a) Encoder Output with Low Resolution Inputsand No Bandpass Transformer

(b) Standard Receiver ResponseGa

inGa

in

X X X X

X X

1.0 2.0 3.0 3.58 4.0 5.0

1.0 2.0 3.0 3.58 4.0 5.0

A final option is shown in Figure 15(b). This circuit providesvery little bandwidth reduction, but enough to remove thechroma to luma feedthrough, with essentially no delay. Thereis, however, about a 9 dB insertion loss from this network.

It will be left to the designer to decide which, if any,compromises are acceptable. Color bars viewed on a goodmonitor can be used to judge acceptability of stepluminance/chrominance alignment and step edge transients,but signals containing the finest detail to be encountered inthe system must also be examined before settling on acompromise.

The Output StageThe output amplifier normally produces about 2.0 Vpp and

is intended to be loaded with 150 as shown in Figure 16.This provides about 1.0 Vpp into 75 , an industry standardlevel (RS343). In some cases, the input to the monitor maybe through a large coupling capacitor. If so, it is necessary toconnect a 150 resistor from Pin 9 to ground to provide a lowimpedance path to discharge the capacitor. The nominalaverage voltage at Pin 9 is over 4.0 V. The 150 dc loadcauses the current supply to rise another 30 mA (toapproximately 60 mA total into Pin 14). Under this (normal)condition the total device dissipation is about 600 mW. Thecalculated worst case die temperature rise is 60C, but thetypical device in a test socket is only slightly warm to thetouch at room temperature. The solid copper 20pin leadframe in a printed circuit board will be even moreeffectively cooled.

MC1377


Figure 14. Optional Chroma Coupling Circuits

0.001 1.0k 0.001

13 10

39pF

56pF 0.001

4.7k 27pF

13 10

1.0k

a) Insertion Loss: 3.0 dBa) Bandwidth: 1.0 MHza) Delay: 100 ns

b) Insertion Loss: 9.0 dBb) Bandwidth: 2.0 MHzb) Delay: 0

22H

Power SuppliesThe MC1377 is designed to operate from an unregulated

10 V to 14 Vdc power supply. Device current into Pin 14 withopen output is typically 35 mA. To provide a stable referencefor the ramp generator and the video output, a high quality8.2 V regulator can supply up to 10 mA for external uses,

with an effective source impedance of less than 1.0 . Thisregulator is convenient for a tracking dc reference for dccoupling the output to an RF modulator. Typical turnon driftfor the regulator is approximately 30 mV over 1 to 2 minutesin otherwise stable ambient conditions.

Figure 15. Output Termination

9

Output

75Monitor

MC1377

4.7k

75 Cable

75

SUMMARYThe preceding information was intended to detail the

application and basis of circuit choices for the MC1377. Acomplete MC1377 application with the MC1374 VHFmodulator is illustrated in Figure 17. The internal schematicdiagram of the MC1377 is provided in Figure 8.

Figure 16. Application with VHF Modulator

3.58MHz

75

RFOut

47k

17

18

2

3

4

5

10

13

14

11 12 19 15 7

6

8

9

1

16

20

10525

220

220

SR

0.1

+

+

+

15

15

15

0.001

3.3k B

G

47

100 220

+12Vdc0.1

0.1

.01 .01

1.2k 1.2k

Delay Line

VideoOut

AudioIn

1.0

0.001

0.001mica

53k 0.1 6.8k120

47

2.2k

VCC470

0.001

470

470

56

0.12H

PALNTSC

8.2VRef 2.7k

+12Vdc

750.33H 0.33H

0.001

22 47 22

5.1k

6 7 4 8

9

12

13105

14

11

2

3

1

MC1377 MC1374

+

10H

+

0.1

Color BandpassTransformer (Fig. 24)

MC1377


APPLICATIONS INFORMATIONSVHS

In full RGB systems (Figure 18), three informationchannels are provided from the signal source to the display topermit unimpaired image resolution. The detail reproductionof the system is limited only by the signal bandwidth and thecapability of the color display device. Also, higher thannormal sweep rates may be employed to add more lineswithin a vertical period and three separate projection picturetubes can be used to eliminate the shadow mask limitationsof a conventional color CRT.

Figure 21 shows the baseband components of a studioNTSC signal. As in the previous example, energy isconcentrated at multiples of the horizontal sweep frequency.The system is further refined by precisely locating the colorsubcarrier midway between luminance spectral components.This places all color spectra between luminance spectra andcan be accomplished in the MC1377 only if full interlacedexternal color reference and sync are applied. The individual

components of luminance and color can then be separatedby the use of a comb filter in the monitor or receiver. Thistechnique has not been widely used in consumer products,due to cost, but it is rapidly becoming less expensive andmore common. Another technique which is gaining popularityis SVHS (Super VHS).

In SVHS, the chroma and luma information are containedon separate channels. This allows the bandwidth of both thechroma and luma channels to be as wide as the monitorsability to reproduce the extra high frequency information. Anoutput coupling circuit for the composite chroma using theTOKO transformer is shown in Figure 19. It is composed ofthe bandpass transformer and an output buffer and has thefrequency performance shown in Figure 20. The compositeoutput (Pin 9) then produces the luma information as well ascomposite sync and blanking.

Figure 17. Spectra of a Full RGB System

Figure 18. SVHS Output Buffer

Figure 19. Frequency Response ofChroma Coupling Circuit

2.7 3.66 4.5

f, MHz

6 dB

Red

Green

Blue

1.0 2.0 3.0 48f, FREQUENCY (MHz)

13100/62pF*

220

+12Vdc0.1F

** 47/33pF* 3.3k 8.2k 6.8k

75 CompositeChroma

Out

+12Vdc

3316k1.0F

1000pF

**Refers to different component values used for NTSC/PAL (3.58 MHz/4.43 MHz).**Toko 166NNF1026AG

MC1377


I/Q System versus (RY)/(BY) SystemThe NTSC standard calls for unequal bandwidths for I and

Q (Figure 21). The MC1377 has no means of processing theunequal bandwidths because the I and Q axes are not used(Figure 22) and because the outputs of the (RY) and the(BY) modulators are added before being output at Pin 13.Therefore, any bandwidth reduction intended for the chromainformation must be performed on the composite chromainformation. This is generally not a problem, however, sincemost monitors compromise the standard quite a bit.

Figure 23 shows the typical response of most monitorsand receivers. This figure shows that some crosstalkbetween luma and chroma information is always present.The acceptability of the situation is enhanced by the limitedability of the CRT to display information above 2.5 MHz. If thesignal from the MC1377 is to be used primarily to driveconventional noncomb filtered monitors or receivers, itwould be best to reduce the bandwidth at the MC1377 to thatof Figure 23 to lessen crosstalk.

I(123)

Figure 20. NTSC Standard Spectral Content

Luminance Q Colo

rSu

bcarr

ier

Soun

dSu

bcarr

ier

0 1.0 2.0 3.0 4.0

Video

Ampli

tude

f, FREQUENCY (MHz)

Figure 21. Color Vector Relationship(Showing Standard Colors)

Figure 22. Frequency Response ofTypical Monitor/TV

Gain

3.582.0 3.01.0 4.0

LuminanceChannel

ChromaChannel

f, FREQUENCY (MHz)

(RY)(90)Red(104)

Yellow(168)

Color Burst(180)

Green(241)

Cyan(284)

Blue(348)

(BY) 0

Q (33)

Purple(61)I

MC1377


Figure 23. A Prototype Chroma Bandpass TransformerToko Sample Number 166NNF10264AG

7 0.2mm

0.7mm Pin Diameter15.0mm Max 3.5mm 0.5mm

Unloaded Q (Pins 13): 15 @ 2.5 MHzInductance: 30 H 10% @ 2.5 MHzTurns: 60 (each winding)Wire: #38 AWG (0.1 m/m)

Connection DiagramBottom View

(Drawing Provided By:Toko America, Skokie, IL)

Time DelayImpedanceResistanceTransient Response with 20 nsRise Time Input Pulse

Attenuation

Item Specifications

3

2

1

4

5

S S

Figure 24. A Prototype Delay LineTDK Sample Number DL122301D1533

1.26 Max32.0

0.93 Max23.5

0.2 0.045.0 1.0

*Marking

0.394 0.0610.0 1.5

0.8 Radius Max2.0

0.788 0.0820.0 2.0

0.026 0.0020.65 0.33

0.35 Max9.0

*Marking: Part Number, Manufacturers Identification,*Marking: Date Code and Lead Number. *Marking: Skokie, IL (TDK Corporation of America)

400 ns 10%1200 10%Less Than 15 Preshoot: 10% MaxOvershoot: 10% MaxRise Time: 120 ns Max3 dB Max at 6.0 MHz

MC1377


Figure 25. RGB Pulse Generator

RGB Pulse Generator Timing Diagram for NTSC

64 s

Yellow Green Red BlackWhite Cyan Magenta Blue

1.0 Vpp

154 kHzClock

BlueOutput

Red Output

Green Output

CompositeBlankingInput

2.2k

3.3k

3.3k

2.2 k

10 k

470

1.8k 1.8k 680 1.8k 680

470470

4.7F10k

10k

10k

0.1

0.1

0.1

0.1 0.1

0.1

0.1 0.1 0.1

10k

FreqAdj

680

750 pF

8 R10

1/2 MC74LS112A

5.0VReg

BNC

CompositeBlanking

2N4403

2N4401

MC1455

MC74LS112A

BNCBlueOutput

BNCRedOutput

BNCGreenOutput

2N44012N44012N4401

7

2

6

48

351

3J15S 16

2k

13C Q71C Q6R4

Q5

12k

11J14S

Q9 3J15S 16

2k

1C Q6R4

8

154kHz

MC1377


Figure 26. Printed Circuit Boards for the MC1377

(CIRCUIT SIDE) (COMPONENT SIZE)

Figure 27. Color TV Encoder Modulator

470 470

470

2.7k 2.2k

47k

3.3k

2201.2k 1.2k

75k

5.1k

6.8k54k

75

1.0

22 47 22

47

120

0.001

220

220

0.1

0.1

15F

15F

15F

0.00147

0.001

56

0.001

0.1 .01

0.1.01

17

18

2

3

4

5

10

13

1411 12 19 15 7

6

8

9

1

16

20

16 7 4 8

9

12

13105

14

11

2

3

0.12H

0.33H0.33HRFOut

10H

+400ns

3.58MHz

525

R

G

B

+

+

+

+

VCC

VideoOut

AudioIn

VCC(+12V)

10264100AG

MC1377MC1374

8.2Vdc

0.1

0.001mica

(+12V)VCC

S

MC1377


OUTLINE DIMENSIONS

NOTES:1. DIMENSIONING AND TOLERANCING PER

ANSI Y14.5M, 1982.2. CONTROLLING DIMENSION: INCH.3. DIMENSION L TO CENTER OF LEAD WHEN

FORMED PARALLEL.4. DIMENSION B DOES NOT INCLUDE MOLD

FLASH.

M

J 20 PLMBM0.25 (0.010) T

DIM MIN MAX MIN MAXMILLIMETERSINCHES

A 25.66 27.171.010 1.070B 6.10 6.600.240 0.260C 3.81 4.570.150 0.180D 0.39 0.550.015 0.022

G 2.54 BSC0.100 BSCJ 0.21 0.380.008 0.015K 2.80 3.550.110 0.140L 7.62 BSC0.300 BSCM 0 15 0 15 N 0.51 1.010.020 0.040

E1.27 1.770.050 0.070

1

11

10

20

A

SEATINGPLANE

K

NFG

D 20 PL

T

MAM0.25 (0.010) T

E

B

C

F1.27 BSC0.050 BSC

NOTES:1. DIMENSIONING AND TOLERANCING PER

ANSI Y14.5M, 1982.2. CONTROLLING DIMENSION: MILLIMETER.3. DIMENSIONS A AND B DO NOT INCLUDE

MOLD PROTRUSION.4. MAXIMUM MOLD PROTRUSION 0.150 (0.006)

PER SIDE.5. DIMENSION D DOES NOT INCLUDE DAMBAR

PROTRUSION. ALLOWABLE DAMBARPROTRUSION SHALL BE 0.13 (0.005) TOTALIN EXCESS OF D DIMENSION AT MAXIMUMMATERIAL CONDITION.

A

B

20

1

11

10

SAM0.010 (0.25) B STD20X

MBM0.010 (0.25)P10X

J

F

G18X K

C

T SEATINGPLANEM

R X 45

DIM MIN MAX MIN MAXINCHESMILLIMETERS

A 12.65 12.95 0.499 0.510B 7.40 7.60 0.292 0.299C 2.35 2.65 0.093 0.104D 0.35 0.49 0.014 0.019F 0.50 0.90 0.020 0.035G 1.27 BSC 0.050 BSCJ 0.25 0.32 0.010 0.012K 0.10 0.25 0.004 0.009M 0 7 0 7 P 10.05 10.55 0.395 0.415R 0.25 0.75 0.010 0.029

P SUFFIXPLASTIC PACKAGE

CASE 73803ISSUE E

DW SUFFIXPLASTIC PACKAGE

CASE 751D04(SO20L)ISSUE E

MC1377


Motorola reserves the right to make changes without further notice to any products herein. Motorola makes no warranty, representation or guarantee regardingthe suitability of its products for any particular purpose, nor does Motorola assume any liability arising out of the application or use of any product or circuit, andspecifically disclaims any and all liability, including without limitation consequential or incidental damages. Typical parameters can and do vary in differentapplications. All operating parameters, including Typicals must be validated for each customer application by customers technical experts. Motorola doesnot convey any license under its patent rights nor the rights of others. Motorola products are not designed, intended, or authorized for use as components insystems intended for surgical implant into the body, or other applications intended to support or sustain life, or for any other application in which the failure ofthe Motorola product could create a situation where personal injury or death may occur. Should Buyer purchase or use Motorola products for any suchunintended or unauthorized application, Buyer shall indemnify and hold Motorola and its officers, employees, subsidiaries, affiliates, and distributors harmlessagainst all claims, costs, damages, and expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or deathassociated with such unintended or unauthorized use, even if such claim alleges that Motorola was negligent regarding the design or manufacture of the part.Motorola and are registered trademarks of Motorola, Inc. Motorola, Inc. is an Equal Opportunity/Affirmative Action Employer.

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