GENNUM GB4600

GB4600 Monolithic
Unity Gain Video Buffer
DATA SHEET
FEATURES
DESCRIPTION
• wideband, unity gain, stable operation
(± 0.1 dB at 100 MHz when CL = 27 pF)
(full power BW = 120 MHz when CL = 47 pF).
The GB4600 is a high performance, monolithic unity gain
video buffer made on Gennum's proprietary LSI process.
The device features a stable wideband topology capable
of driving high capacitance video busses.
• selectable high and low current operating
modes (I L = 10 mA or I L = 20 mA)
• drives high capacitance loads (CL = 180 pF)
to 70 MHz at -3 dB.
• extremely low differential phase and gain
• convenient 8 pin SOIC packaging
• 100 mW disabled power consumption
FUNCTIONAL BLOCK DIAGRAM
INPUT
VIDEO
SWITCH
OUTPUT
Optimal system power/bandwidth can be achieved by
using the high/low current mode select (I-SET). In addition,
the GB4600 can be disabled by taking the ENABLE pin to
ground. The ENABLE input is TTL and 5 V CMOS compatible.
The GB4600 operates from ± 4.5 to ± 5.5 V power supplies
and typically draws 30 mA of current when I -SET is not
connected. The supply current drops by approximately
50% when I -SET is directly connected to VEE.
A typical application for the GB4600 is interfacing Gennum's
wide range of video crosspoint switches. The 8 pin SOIC
packaging is ideally suited for space restricted board
layouts.
APPLICATIONS
• Input and output buffering in wide crosspoint matrices
• Inter-board video signal buffering
ENABLE
ENABLE
CURRENT SET
I-SET
• Inter-system video signal buffering
AVAILABLE PACKAGING
8 pin SOIC
PIN CONNECTIONS
ORDERING INFORMATION
ENABLE
11
85
GND
V EE
22
76
INPUT
V CC
33
67
NC
OUTPUT
44
58
I-SET
Part Number
Package
Temperature Range
GB4600-CKA
8 SOIC
0° to 70°C
Revision Date: February 2003
Document No. 13421 - 5
GENNUM CORPORATION P.O. Box 489, Stn A, Burlington, Ontario, Canada L7R 3Y3 tel. (905) 632-2996 fax: (905) 632-5946
Japan Branch: A-302, Miyamae Village, 2-10-42, Miyamae, Suginami-ku, Tokyo 168, Japan
tel. (03) 3334-7700
fax. (03) 3247-8839
ABSOLUTE MAXIMUM RATINGS
PARAMETER
VALUE
Supply Voltage
Operating Temperature Range
0°C to 70°C
Storage Temperature Range
Analog Input Voltage
260°C
-5.5 V £ V IN £ 5.5 V
-0.5 V £ VL £ 5.5 V
Logic Input Voltage
ELECTRICAL CHARACTERISTICS
VS = ±5 V, T A = 0° to 70°C, RL = 10kW, CL = 47 pF, R- SET = open circuit unless otherwise shown.
PARAMETER
Supply Voltage
Supply Current
DC
SUPPLY
VS
MIN.
TYP.
MAX.
UNITS
±4.5
±5.0
±5.5
V
I+
-
30
37
mA
I-
-
30
37
mA
I+
R-SET = 0 W
-
16
20
mA
I-
-
16
20
mA
Enable = 0
-
0
-
mA
I - (off)
Enable = 0
-
16
50
mA
-1.8
-
2.2
V
-
12
-
mA
5
-
15
mV
DVOS
-
50
100
mV/°C
Chip Enable Time
t ON
-
100
-
ns
Chip Disable Time
tOFF
-
1
-
ms
Logic Input Thresholds
VIH
2.0
-
-
V
VIL
-
-
0.8
V
Analog Output Voltage
VOUT
Analog Input Bias Current
IVBIAS
Output Offset Voltage
VOS
Unclipped Extremes
TA = 25°C
-
I BIAS
Enable = 0, TA = 25°C
-
-
5.0
mA
Insertion Loss
I.L.
ƒ = 100 kHz, TA = 25°C
-
-0.04
-
dB
Frequency Response (±0.1dB)
F.R.
VIN = 1 V p-p CL = 27 pF
-
100
-
MHz
VIN = 1 V p-p,
-
120
-
MHz
Full Power (-3dB)
FPBW
Input Resistance
RIN
1.0
3.0
-
MW
Input Capacitance
CIN
-
1.1
-
pF
Output Resistance
ROUT
-
2
-
W
Output Capacitance
COUT
-
5
-
pF
Differential Gain
dg
ƒ = 3.58 MHz
-
0.02
-
%
Differential Phase
dp
ƒ = 3.58 MHz
-
0.02
-
deg
VIN = 1 V p-p
75
80
-
dB
-
250
-
V/ms
Off Isolation at 30 MHz
+SR
Slew Rate
13421 - 5
CONDITIONS
R-SET = 0 W
Enable Bias Current
DYNAMIC
SYMBOL
I + (off)
Output Offset Voltage Drift
LOGIC
DO NOT OPEN PACKAGES OR HANDLE
EXCEPT AT A STATIC-FREE WORKSTATION
-65°C to 150°C
Lead Temperature (soldering 10 sec.)
STATIC
CAUTION
ELECTROSTATIC
SENSITIVE DEVICES
±7.5 V
R-SET = 0 (I minimum)
VIN = 3 V p-p, CL = 100 pF
-SR
RS = 12 W
-
100
-
V/ms
+SR
VIN = 3 V p-p, CL = 100 pF
-
350
-
V/ms
-SR
RS = 12 W
-
170
-
V/ms
2
+5V
TALLY OUT
0.1
GX4201
VIDEO OUT
10K
3
VIDEO INPUT
75
TALLY OUT
1
7
GB4600
4
8
2
5
GX4201
27
TALLY OUT
CL
*R-SET
0.1
VIDEO OUT
-5V
VIDEO OUT
GX4201
-5V
All resistors are in ohms, all capacitors in microfarads unless otherwise stated
* The current will be maximum if the pin 5 is left open circuit. Any value of resistance from pin 5 to -VEE will reduce the current. The minimum current
(50% of max.) will occur when R-SET = 0 W.
TYPICAL APPLICATION CIRCUIT
The circuit shown above uses the GB4600 as an input
buffer driving several GX4201 video crosspoint ICs.
For other applications, the ENABLE input on the GB4600
may be controlled by any TTL or 5 volt CMOS device.
The GB4600 is capable of driving loads up to 100 pF to
a -3 dB bandwidth of 80 MHz. For lighter loads, the
bandwidth is extended to over 100 MHz.
A unique feature of the GB4600 is that its current drain
can be reduced by adjusting the value of the resistor on
the I-SET input, pin 5.
Capacitor CL is used to shape the response in conjunction
with the 27 W series resistor from pin 4. The value shown
will give a -1 dB response at 100 MHz with a total load
capacitance (fixed plus actual) of 47 pF.
If R-SET is made zero ohms (a direct connection to -VEE)
then the supply current drops 50% from 36 mA to 18 mA.
A reduced current will reduce the bandwidth as shown
in Figure 3. For values of RS = 27 W and CL = 47 pF, the
-1 dB bandwidth shrinks from 100 MHz at maximum
current to 80 MHz at minimum current.
In order to disable the GB4600, pin 1 is driven from the
TALLY outputs of the GX4201s. When all crosspoints are
OFF, the voltage on pin 1 will be 0 volts, disabling the
GB4600. Whenever any crosspoint is selected, the
voltage on pin 1 rises to +5 volts and turns on the buffer.
This configuration minimizes the current drain when a
group of crosspoints are turned off.
+5V
As with any high frequency circuit, careful board layout
with ample ground plane is critical.
CHIP ENABLE
+5V
0.1
3
VIDEO INPUT
7
75
8
10 K
1
GB4600
4
2
5
RS
4
CL
0.1
-5V
0.1
0.1
RL
10 K
1
COMLINEAR
CLC110
8
VIDEO OUT
(75 W )
5
0.1
-5V
Max. Min.
I-SET
-5V
All resistors are in ohms, all capacitors in microfarads unless otherwise stated
TEST CIRCUIT
3
13421 - 5
TYPICAL PERFORMANCE CURVES FOR THE GB4600
40
1.5
OFF ISOLATION (dB)
1.0
VIN = 1V p-p
50
0.5
GAIN (dB)
70
80
90
100
ISET = MAX.
0
60
1
10
100
-0.5
-1.0
-1.5
-2.0
RS = 27W
-2.5
CL = 47pF
-3.0
V IN = 1V p-p
-3.5
300
I SET = MIN.
10
10
100
Fig. 1
Off - Isolation vs Frequency
Fig. 3
1.5
V BLANKING = 0V
0.5
V LUMINENCE = 0.714V
0.04
dg/dp
GAIN (d B)
0
-0.5
RS = 18W
-1.0
CL = 100pF
-1.5
I-SET Bandwidth vs Frequency
0.05
RS = 12W
1.0
200200
FREQUENCY (MHz)
FREQUENCY (MHZ)
VIN = 40 IRE
0.03
dg
0.02
VIN = 1V p-p
-2.0
dp
0.01
-2.5
-3.0
-3.5 1
1
0
100100
10
1
3
Fig. 2
5
10
FREQUENCY (MHz)
FREQUENCY (MHz)
Fig. 4
Full Power Bandwidth (100 pF) vs Frequency
Differential Gain and Phase vs Frequency
75
o
AMBIENT TEMPERATURE ( C)
80
(STILL AIR)
70
VS = ±5.0V
65
60
VS = ±5.3V
55
VS = ±5.5V
50
45
40
100
1K
10K
1M
R-SET (W)
Fig. 5
SOIC Derating Curves
DOCUMENT IDENTIFICATION
REVISION NOTES:
Remove reference to DIP Package.
Remove associated part number from DIP package.
DATA SHEET
The product is in production. Gennum reserves the right to make
changes at any time to improve reliability, function or design, in
order to provide the best product possible.
Gennum Corporation assumes no responsibility for the use of any circuits described herein and makes no representations that they are free from patent infringement.
© Copyright May 1991 Gennum Corporation. All rights reserved. Printed in Canada.
13421 - 5
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