LM1205N National Semiconductor, LM1205N Datasheet - Page 16

• Manufacturer Part Number: LM1205N
• Description: IC VIDEO AMP 130MHZ RGB 28DIP
• Manufacturer: National Semiconductor

Specifications of LM1205N

• Applications: General Purpose
• Number Of Circuits: 3
• -3db Bandwidth: 130MHz
• Current - Supply: 90mA
• Current - Output / Channel: 28mA
• Voltage - Supply, Single/dual (±): 10.8 V ~ 13.2 V
• Mounting Type: Through Hole
• Package / Case: 28-DIP (0.600", 15.24mm)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: *LM1205N

Figure 13 is a simplified schematic of the Blank Gate circuit
Circuit Description
comparators of the three video channels Q103 is added to
help drive the base of Q86 in the clamp comparator in-
creasing the accuracy of the current mirror Q101 drives
R79 and R80 This sets the current thru Q102 thus setting
the current thru Q86 of the clamp comparator
BLANK GATE CIRCUIT
With the exception of the simple output stage this circuit is
almost identical to the clamp gate circuit The only differ-
FIGURE 12 Simplified Schematic of LM1205 Clamp Gate Circuit
(Continued)
16
ence is that the output stage is driven from the opposite
side of the differential pair Thus Q111 is connected as a
diode instead of Q109 With the input at pin 13 at a low level
Q108 is turned on also turning on Q29 the output transis-
tor Q29 is part of the blanking circuit in the output stage
shown in Figure 14 When Q29 is turned on the output is
clamped to a blanking level that is ‘‘blacker than black’’
allowing blanking to be done on the cathodes of the CRT
TL H 11831 – 16