GB4551 Video Buffer with
Strobed DC Restore
DATA SHEET
FEATURES
•
accurate clamping to within
±
1mV
•
ultra low differential gain (0.03% typ.)
and differential phase (0.03
o
typ.)
•
wideband unity gain, can typically be flattened to
±
0.1dB at 30MHz
•
can be configured as a gain stage with reduced
bandwidth.
•
drives 100pF loads
•
convenient 8 pin SIP packaging
DESCRIPTION
The GB4551 is a high performance video buffer with DC
restore primarily used for accurate back porch clamping.
The circuit features a wideband differential amplifier that
can be configured as a gain stage. The output signal
voltage is limited to +2V above the clamp level in order to
prevent damage to crosspoints or other circuits connected
to the output.
The clamping action occurs when the STROBE (STB)
input is taken to ground. A typical application would be for
DC restoration during the back porch period. In this case
the negative-going back porch pulse would be derived
from an external sync separator circuit.
The GB4551 will operate from
±
9V to
±
12V power supplies
and will directly interface with Gennum’s video crosspoint
switches. The 8 pin SIP package is ideally suited for
space restricted board layouts.
GB4551
APPLICATIONS
• Input buffering and DC restoration to crosspoint switches
1
2
3
4
5
6
7
8
• Accurate back porch video signal clamping
• Inter-circuit buffering and DC restoration.
PIN CONNECTIONS
Pin No.
1
2
3
4
5
6
7
8
GB4551
+IN
V
CC
STB
GND
C
X
V
EE
- IN
OUT
Function
non-inverting input
positive power supply
strobe
ground
external capacitor
negative power supply
inverting input
output
–IN
C
X
(+2V OUTPUT CLAMP)
+IN
10k
500
30k
+
12pF
-
+
10k
-
ORDERING INFORMATION
STROBE
7mA
NOM.
V
EE
V
CC
All resistors in ohms, all capacitors in microfarads unless otherwise stated.
OUT
Part Number
GB4551-CSA
Package Type
8 Pin SIP
Temperature Range
0 to 70
o
C
GND
SIMPLIFIED CIRCUIT DIAGRAM
Document No. 520 - 52 - 2
GENNUM CORPORATION P.O. Box 489, Stn A, Burlington, Ontario, Canada L7R 3Y3
Japan Branch: B-201 Miyamae Village, 2-10-42 Miyamae, Suginami-ku Tokyo 168, Japan
tel. (905) 632-2996 fax: (905) 632-2055
tel. (03) 3247-8838
fax: (03) 3247-8839
GENNUM [ GENNUM CORPORATION ]
