LM1203A.pdf

January 1996

LM1203A

150 MHz RGB Video Amplifier System

General Description

The LM1203A is an improved version of the popular

LM1203 wideband video amplifier system. The device is in-

tended for high resolution RGB CRT monitors. In addition to

three matched video amplifiers, the LM1203A contains

three gated differential input black level clamp comparators

for brightness control and three matched attenuator circuits

for contrast control. Each video amplifier contains a gain set

or ``Drive'' node for setting maximum system gain or provid-

ing gain trim capability for white balance. The LM1203A also

contains a voltage reference for the video inputs. The

LM1203A is pin and function compatible with the LM1203.

Features

Y Three wideband video amplifiers 150 MHz @ b 3dB

Y Matched ( g 0.1 dB or 1.2%) attenuators for contrast

control

Y Three externally gated comparators for brightness

control

Y Provisions for individual gain control (Drive) of each

video amplifier

Y Video input voltage reference

Y Low impedance output driver

Improvements over LM1203

Y 150 MHz vs 70 MHz bandwidth

Y V OUT low: 0.15V vs 0.9V

Y t r ,t f :4nsvs7ns

Y Built in power down spot killer

Applications

Y High resolution RGB CRT monitors

Y Video AGC amplifiers

Y Wideband amplifiers with gain and DC offset controls

Block and Connection Diagrams

TL/H/11441±1

FIGURE 1

Order Number LM1203AN

See NS Package Number N28B

C 1996 National Semiconductor Corporation

TL/H/11441

RRD-B30M66/Printed in U. S. A.

Absolute Maximum Ratings (Note 1)

If Military/Aerospace specified devices are required,

please contact the National Semiconductor Sales

Office/Distributors for availability and specifications.

Supply Voltage (V CC )

Pins 1, 13, 23, 28 (Note 3)

Thermal Resistance ( i JA )

50 § C/W

Junction Temperature (T J )

150 § C

ESD Susceptibility (Note 4)

2 kV

13.5V

Storage Temperature

b 65 § Cto150 § C

Lead Temperature (Soldering, 10 sec.)

265 § C

Peak Video Output Source Current

(Any One Amp) Pins 16, 20 or 25 28 mA

Voltage at Any Input Pin (V IN ) V CC t V IN t GND

Power Dissipation, (P D ) (Above 25 § C derate

based on i JA and T J )

Operating Ratings (Note 2)

Temperature Range

b 20 § Cto a 80 § C

2.5W

Supply Voltage (V CC )

10.8V s V CC s 13.2V

DC Electrical Characteristics See Test Circuit (Figure2),T A e 25 § C; V CC1 e V CC2 e 12V. S17, 21, 26

Open; V12 e 6V; V14 e 0V; V15 e 2.0V unless otherwise stated.

Symbol

Parameter

Conditions

Typical

Limit

Units

(Note 5)

(Note 6)

I S

Supply Current

V CC1 a V CC2 ,R L e % (Note 7)

95 mA (max)

V11

Video Input Reference Voltage

2.8

2.5

V (min)

3.1

V (max)

I B

Video Input Bias Current

Any One Amplifier

m A (max)

V 14L

Clamp Gate Low Input Voltage Clamp Comparators On

1.2

0.8

V (max)

V 14H

Clamp Gate High Input Voltage Clamp Comparators Off

1.6

2.0

V (min)

I 14L

Clamp Gate Low Input Current V14 e 0V

b 1 b 5.0

m A (max)

I 14H

Clamp Gate High Input Current V14 e 12V

0.07

0.2

m A (max)

I CLAMP a

Clamp Cap Charge Current

V5, 8 or 10 e 0V

750

500

m A (min)

I CLAMP b

Clamp Cap Discharge Current V5, 8 or 10 e 5V

b 750 b 500

m A (min)

V OL

Video Output Low Voltage

V5, 8 or 10 e 0V

0.15

0.5

V (max)

V OH

Video Output High Voltage

V5, 8 or 10 e 5V

7.5

V (min)

D V O(2V) Video Output Offset Voltage

Between Any Two

g 25 mV (max)

Amplifiers, V15 e 2V

D V O(4V) Video Output Offset Voltage

Between Any Two

g 25 mV (max)

Amplifiers, V15 e 4V

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AC Electrical Characteristics See Test Circuit (Figure2),T A e 25 § C; V CC1 e V CC2 e 12V. S17, 21, 26

Closed; V14 e 0V; V15 e 4V unless otherwise stated.

Symbol

Parameter

Conditions

Typical

Limit

Units

(Note 5)

(Note 6)

A V max

Video Amplifier Gain

V12 e 12V, V IN e 560 mV PP

6.5

4.5

V/V (min)

D A V5V

Attenuation @ 5V

Ref: A V max, V12 e 5V

b 8

D A V2V

Attenuation @ 2V

Ref: A V max, V12 e 2V

b 30

A V match

Absolute Gain Match @ A V max V12 e 12V (Note 8)

g 0.3

D A V track 1 Gain Change Between Amplifiers V12 e 5V (Notes 8, 9)

g 0.1

D A V track 2 Gain Change Between Amplifiers V12 e 5V (Notes 8, 9)

g 0.3

THD

Video Amplifier Distortion

V12 e 3V, V O e 1V PP

f( b 3 dB)

Video Amplifier Bandwidth

V12 e 12V, V O e 4V PP

100

MHz

(Notes 10, 11)

(No External Peaking Capacitor)

f( b 3 dB)

Video Amplifier Bandwidth

V12 e 12V, V O e 4V PP

(Notes 10, 11)

With 18 pF Peaking Cap from

150

MHz

Pins 18, 22 and 27 to GND

t r

Output Rise Time (Note 10)

V O e 4V PP

(No External Peaking Capacitor)

t f

Output Fall Time (Note 10)

V O e 4V PP

(No External Peaking Capacitor)

V sep 10 kHz Video Amplifier 10 kHz Isolation V12 e 12V (Note 12)

b 70

V sep 10 MHz Video Amplifier 10 MHz Isolation V12 e 12V (Notes 10, 12)

b 50

Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur.

Note 2: Operating Ratings indicate conditions for which the device is functional, but do not guarantee specific performance limits. For guaranteed specifications

and test conditions, see the Electrical Characteristics. The guaranteed specifications apply only for the test conditions listed. Some performance characteristics

may degrade when the device is not operated under the listed test conditions.

Note 3: V CC supply pins 1, 13, 23, 28 must be externally wired together to prevent internal damage during V CC power on/off cycles.

Note 4: Human body model, 100 pF discharged through a 1.5 k X resistor.

Note 5: Typical specifications are specified at a 25 § C and represent the most likely parametric norm.

Note 6: Tested limits are guaranteed to National's AOQL (Average Outgoing Quality Level).

Note 7: The supply current specified is the quiescent current for V CC1 and V CC2 with R L e % , see Figure2's test circuit. The supply current for V CC2 (pin 23) also

depends on the output load. With video output at 2V DC, the additional current through V CC2 is 18 mA for Figure2's test circuit.

Note 8: Measure gain difference between any two amplifiers. V IN e 1V PP .

Note 9: D A V track is a measure of the ability of any two amplifiers to track each other and quantifies the matching of the three attenuators. It is the difference in gain

change between any two amplifiers with the contrast voltage (V12) at either 5V or 2V measured relative to an A V max condition, V12 e 12V. For example, at

A V max the three amplifiers' gains might be 17.4 dB, 16.9 dB and 16.4 dB and change to 7.3 dB, 6.9 dB, and 6.5 dB respectively for V12 e 5V. This yields the

measured typical g 0.1 dB channel tracking.

Note 10: When measuring video amplifier bandwidth or pulse rise and fall times, a double sided full ground plane printed circuit board without socket is

recommended. Video amplifier 10 MHz isolation test also requires this printed circuit board.

Note 11: Adjust input frequency from 10 kHz (A V max reference level) to the b 3 dB corner frequency (f b 3dB ).

Note 12: Measure output levels of the other two undriven amplifiers relative to the driven amplifier to determine channel separation. Terminate the undriven

amplifier inputs to simulate generator loading. Repeat test at f IN e 10 MHz for V sep e 10 MHz.

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TL/H/11441±2

FIGURE 2. LM1203A Test Circuit

Typical Performance Characteristics V CC e 12V, T A e 25 § C unless otherwise specified

Contrast vs Frequency

TL/H/11441±3

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Typical Performance Characteristics V CC e 12V, T A e 25 § C unless otherwise specified (Continued)

Crosstalk vs Frequency

TL/H/11441±4

Frequency Response Using Various Peaking Caps

TL/H/11441±5

Attenuation vs Contrast Voltage

TL/H/11441±6

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