Required Rise Time

at CRT

APPLICATION NOTES CON'T

The brightness (output offset) can be linearly adjusted by

output quiescent voltage range is from approximately (5µA)

should be bypassed with a 0.1µF capacitor to ground placed as

close as possible to the hybrid. This DC voltage can be any

stable system source.

Keep hybrid power dissipation in mind when adjusting the

output quiescent voltage. Practically all of the voltage is seen

across Rp. This power must be taken into account when high

Rp currents are used. If the quiescent level is set too close to

will suffer slightly. If the quiescent level is set too far from

output fall time will be limited. The output black level is obvi-

ously dependent on system requirements but a little experi-

mentation will strike the optimum balance between power dis-

sipation and bandwidth. Total current through Rp should be

limited to less than 290mA when operating from power sup-

plies greater than 90V. The gain adjust alone can set the AC

current to 250mA (ie: 250mApp=100Vpp/400

Ω). This would

leave about 40mA left for black level output current.

BLANK INPUT

The video input can be electrically disconnected from the

amplifier by applying a TTL high input to the blank pin. When

put when it is in blank mode.

When the TTL compatible blank input is not used, the pin

must be connected to ground to enable the amplifier. The blank

input will float high when left disconnected which will disable

the video.

The MSK 1903 has an on board buffered DC zener reference

perature test limits of 5.2V to 5.8V DC. This output is provided

for gain and offset adjustment and can source up to 4mA of

current.

THERMAL MANAGEMENT

The MSK 1903 package has mounting holes that allow the

user to connect the amplifier to a heat sink or chassis. Since

the package is electrically isolated from the internal circuitry,

mounting insulators are not required or desired for best thermal

performance. Use 4 to 6 inch/pounds for mounting the device

to the heat sink.

The power dissipation of the amplifier depends mainly on the

load requirements, bandwidth, pixel size, black level and the

value of Rp. The following table illustrates a few examples:

320 x 200

640 x 350

640 x 480

800 x 560

1024 x 900

1024 x 1024

1280 x 1024

1664 x 1200

2048 x 2048

4096 x 3300

Maximun

Pixel

Time

182nS

52nS

38nS

26nS

12.6nS

11nS

8.9nS

5.8nS

2.8nS

860pS

Minimum Pixel

Clock

Frequency

5MHz

19MHz

26MHz

38MHz

80MHz

90MHz

112MHz

170MHz

360MHz

1.2GHz

60nS

17nS

12.5nS

8.6nS

4.2nS

3.7nS

2.9nS

1.9nS

1nS

280pS

Required System

Bandwidth

6MHz

20MHz

28MHz

41MHz

84MHz

95MHz

120MHz

180MHz

380MHz

1.23GHz

RESOLUTION TABLE FOR A TYPICAL CRT

All data assumes retrace time equal to 30% of frame time and a 60Hz refresh rate.

This table does not include power dissipation due to output switching since this is dependent on individual load requirements. The input stage power

dissipation is typically 2.5 watts and is essentially independent of output levels.

Display

Resolution

Rev. B 3/03

4

1903-6

1903-6

1903-4

1903-4

-120V

-120V

-70V

-70V

0W

13.3W

0W

8.4W

2.5W

15.7W

2.5W

10.6W

WHITE

0%

40%

0%

40%

BLANK

100%

20%

100%

20%

0V

-90V

0V

-50V

-20V

-20V

-15V

-15V

-110V

-110V

-65V

-65V

-VHV

BLACK

0%

40%

0%

40%

PERCENT OF SIGNAL

TYPE

DEVICE

LEVEL

BLACK

LEVEL

WHITE

VOLTAGE

OUTPUT

AVE. Pd

OUTPUT

AVE. Pd

TOTAL