LM1202M National Semiconductor, LM1202M Datasheet - Page 13

• Manufacturer Part Number: LM1202M
• Description: IC VIDEO AMP SYST 230MHZ 20SOIC
• Manufacturer: National Semiconductor

Specifications of LM1202M

• Applications: General Purpose
• Number Of Circuits: 1
• -3db Bandwidth: 230MHz
• Current - Supply: 48mA
• Current - Output / Channel: 28mA
• Voltage - Supply, Single/dual (±): 8 V ~ 13.2 V
• Mounting Type: Surface Mount
• Package / Case: 20-SOIC (0.300", 7.50mm Width)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: *LM1202M

Figure 9 The video signal is AC coupled to pin 6 The
Applications of the LM1202
SINGLE VIDEO CHANNEL
A typical application for a single video channel is shown in
LM1202 internally biases the video signal to 2 6 V
trast control is achieved by applying a 0V to 4V DC voltage
at pin 8 The amplifier’s gain is minimum (i e maximum sig-
nal attenuation) if pin 8 is at 0V and is maximum if pin 8 is at
4V With pin 9 (drive control) at 0V the amplifier has a maxi-
mum gain of 10
For DC restoration a clamp signal must be applied to the
clamp gate input (pin 14) The clamp signal should be logic
low (less than 0 8V) only during the back porch (black level
reference period) interval (see Figure 2 ) The clamp gate
input is TTL compatible Brightness control is provided by
applying a 0V to 4V DC voltage at pin 19 For example if pin
19 is biased at 1V then the video signal’s black level will be
clamped at 1V A 510
video output pin (pin 17) to ground This resistor biases the
output stage of the amplifier For power dissipation consid-
erations the load resistor should not be much less than
510
load resistor is connected from the
DC
Con-
13
Figure 10 shows an RGB video preamplifier circuit using
RGB VIDEO PREAMPLIFIER
three LM1202s Note that pins 1 and 2 of IC1 are connected
to pins 1 and 2 of IC2 and IC3 respectively This allows IC1
to provide a master contrast control and optimum contrast
tracking Adjusting the contrast voltage at pin 8 of IC1 will
vary the gain of all three video channels Drive control input
(pin 9) of each LM1202 allows individual gain adjustment for
achieving white balance
The black level of each video channel can be individually
adjusted to the desired voltage by adjusting the voltage at
pin 19 In a DC-coupled cathode drive application adjusting
the voltage at pin 19 of each IC will provide cutoff adjust-
ment In an AC-coupled cathode drive application the video
signal is AC coupled and DC restored at the cathode In
such an application the video signal’s black level may be
clamped to the desired level by simply biasing pin 19 to the
black level voltage by using a voltage divider at pin 19
http
www national com