LM1203.PDF

January 1996

LM1203 RGB Video Amplifier System

General Description

The LM1203 is a wideband video amplifier system intended

for high resolution RGB color monitor applications. In addi-

tion to three matched video amplifiers, the LM1203 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 (Av e 4

to 10) as well as providing trim capability. The LM1203 also

contains a voltage reference for the video inputs. For high

resolution monochrome monitor applications see the

LM1201 Video Amplifier System datasheet.

Features

Y Three wideband video amplifiers (70 MHz @ b 3dB)

Y Inherently matched ( g 0.1 dB or 1.2%) attenuators for

contrast control

Y Three externally gated comparators for brightness con-

trol

Y Provisions for independent gain control (Drive) of each

video amplifier

Y Video input voltage reference

Y Low impedance output driver

Block and Connection Diagram

TL/H/9178±1

FIGURE 1

Order Number LM1203N

See NS Package Number NA28F

C 1996 National Semiconductor Corporation

TL/H/9178

RRD-B30M56/Printed in U. S. A.

Absolute Maximum Ratings

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 1)

13.5V

Storage Temperature Range, T STG b 65 § Cto a 150 § C

Lead Temperature, (Soldering, 10 sec.) 265 § C

ESD susceptibility 1 kV

Human body model: 100 pF discharged through a 1.5 k X

resistor

Voltage at Any Input Pin, V IN

V CC t V IN t GND

Video Output Current, I16, 20 or 25

28 mA

Operating Ratings (Note 9)

Temperature Range

Power Dissipation, P D

2.5W

0 § Cto70 § C

(Above 25 § C) Derate Based on i JA and T J

Thermal Resistance, i JA

50 § C/W

Supply Voltage (V CC )

10.8V s V CC s 13.2V

Junction Temperature, T J

150 § C

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

DC Static Tests S17, 21, 26 Open; V12 e 6V; V14 e 0V; V15 e 2.0V unless otherwise stated

Label

Parameter

Conditions

Typ

Tested Design Units

Limit (Note 2) Limit (Note 3) (Limits)

Supply Current

V CC 1 only

90.0

mA(max)

V11

Video Input Reference Voltage

2.4

2.2

V(min)

2.6

V(max)

Video Input Bias Current

Any One Amplifier

5.0

m A(max)

V14 l Clamp Gate Low Input Voltage Clamp Comparators On

1.2

0.8

V(max)

V14 h Clamp Gate High Input Voltage Clamp Comparators Off

1.6

2.0

V(min)

I14 l

Clamp Gate Low Input Current V14 e 0V

b 0.5 b 5.0

m A(max)

I14 h Clamp Gate High Input Current V14 e 12V

0.005

m A(max)

lclamp a Clamp Cap Charge Current V5, 8 or 10 e 0V

850

500

m A(min)

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

b 850 b 500

m A(min)

Vol

Video Output Low Voltage

V5, 8 or 10 e 0V

0.9

1.25

V(max)

Voh

Video Output High Voltage

V5, 8 or 10 e 5V

8.9

8.2

V(min)

D Vo(2V) Video Output Offset Voltage Between Any Two Amplifiers

g 0.5

g 50

mV(max)

V15 e 2V

D Vo(4V) Video Output Offset Voltage Between Any Two Amplifiers

g 0.5 g 50

mV(max)

V15 e 4V

AC Dynamic Tests S17, 21, 26 Closed; V14 e 0V; V15 e 4V; unless otherwise stated

Symbol

Parameter

Conditions

Typ

Tested Design Units

Limit (Note 2) Limit (Note 3) (Limits)

Av max Video Amplifier Gain

V12 e 12V, V IN e 560 mVp-p 6.0

4.5

V/V(min)

D Av 5V Attenuation @ 5V

Ref: Av max, V12 e 5V b 10

D Av 2V Attenuation @ 2V

Ref: Av max, V12 e 2V b 40

Av match Absolute gain match @ Av max V12 e 12V (Note 5)

g 0.5

D Av track1 Gain change between amplifiers V12 e 5V (Notes 5, 8)

g 0.1

g 0.5

dB(max)

D Av track2 Gain change between amplifiers V12 e 2V (Notes 5, 8)

g 0.3

g 0.7

dB(max)

THD

Video Amplifier Distortion

V12 e 3V, V O e 1 Vp-p

0.5

f( b 3 dB) Video Amplifier Bandwidth

V12 e 12V,

MHz

(Notes 4, 6)

V O e 100 mV rms

t r

Output Rise Time (Note 4)

V O e 4 Vp-p

t f

Output Fall Time (Note 4)

V O e 4 Vp-p

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AC Dynamic Tests S17, 21, 26 Closed; V14 e 0V; V15 e 4V; unless otherwise stated (Continued)

Symbol

Parameter

Conditions

Typ

Tested

Design

Units

Limit (Note 2) Limit (Note 3)

Vsep

Video Amplifier 10 kHz Isolation V12 e 12V (Note 7)

b 65

10 kHz

Vsep

Video Amplifier 10 MHz Isolation V12 e 12V (Notes 4, 7)

b 46

10 MHz

Note 1: 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 2: These parameters are guaranteed and 100% production tested.

Note 3: Design limits are guaranteed (but not 100% production tested). These limits are not used to calculate outgoing quality levels.

Note 4: When measuring video amplifier bandwidth or pulse rise and fall times, a double sided full ground plane printed circuit board without socket is recommend-

ed. Video Amplifier 10 MHz isolation test also requires this printed circuit board.

Note 5: Measure gain difference between any two amplifiers. V IN e 1 Vp-p.

Note 6: Adjust input frequency from 10 kHz (Av max ref level) to the b 3 dB corner frequency (f b 3 dB).

Note 7: Measure output levels of the other two undriven amplifiers relative to driven amplifier to determine channel separation. Terminate the undriven amplifier

inputs to simulate generator loading. Repeat test at f IN e 10 MHz for Vsep e 10 MHz.

Note 8: D Av 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 Av max condition V12 e 12V. For example, at

Av 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 9: Operating Ratings indicate conditions for which the device is functional. See Electrical Specifications for guaranteed performance limits.

*Peaking capacitors. See Frequency Response

using various peaking cups graph on next page.

TL/H/9178±2

FIGURE 2. LM1203 Test Circuit

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Typical Performance Characteristics

Contrast vs Frequency

Crosstalk vs Frequency

TL/H/9178±11

TL/H/9178±12

Frequency Response Using

Various Peaking Caps

Attenuation vs Contrast Voltage

TL/H/9178±14

TL/H/9178±13

Pulse Response

Rise & Fall Times

Vert. e 1V/Div.

Horiz. e 10 ns/Div.

± ± GND

TL/H/9178±15

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TL/H/9178±3

FIGURE 3. LM1203 Typical Application

* 30 X resistors are added to the input pins for protection against current surges coming through the 10 m F input capacitors. By increasing these resistors to well

over 100 X the rise and fall times of the LM1203 can be increased for EMI considerations.

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