GENNUM GT4123B

GT4123B Two Channel
Video Multiplier
DATA SHEET
FEATURES
DESCRIPTION
 two-quadrant video multiplication
The GT4123B is a monolithic dual-channel video multiplier
for use in a wide range of applications including broadcast
and multimedia.
 operation from ±4.5 V to ±13.2 V supply voltages
 20 MHz ±0.1 dB video & control channel bandwidth
 ultra low differential gain & differential phase
Featuring two wideband video inputs and a single control
input, the GT4123B achieves broadcast quality mixing of
two video input signals to a single output by implementing
the function:
 convenient 8 pin package
VO = [ ( VC • VA) + (1 - VC) • VB ]
 Pb-free and Green
where VC is the control input voltage, which may be varied
continuously over the range 0 V to 1 V, and VA and V B are
the video input signals.
APPLICATIONS
The GT4123B is a low power version of the GT4123 and
GT4123A Video Multipliers which operates from ±5 V
supply voltages and typically draws only 15 mA of current.
• Multimedia Graphics Overlay
• Production Switchers
• Linear Keyers
PIN CONNECTIONS
FUNCTIONAL BLOCK DIAGRAM
GT4123B
FREQ
COMP
VIDEO IN A
OUTPUT
1
8
V
FREQ. COMP
2
7
VIDEO IN B
CONTROL
3
6
V
GROUND
4
5
VIDEO IN A
cc
MULTIPLIER
CORE
VIDEO IN B
OUTPUT
EE
CONTROL
VREF (0.5V)
(INTERNAL)
ORDERING INFORMATION
Part
Number
Package
Type
Temperature
Range
Pb-Free
and Green
GT4123BCDA
8 pin PDIP
0° to 70° C
No
GT4123BCKA
8 pin SOIC
0° to 70° C
No
GT4123BCTA
8 pin SOIC Tape
0° to 70° C
No
GT4123BCKAE3
8 pin SOIC
0° to 70° C
Yes
Revision date: July 2004
Document No. 521 - 20 - 02
GENNUM CORPORATION P.O. Box 489, Stn A, Burlington, Ontario, Canada L7R 3Y3 tel. (905) 632-2996 fax: (905) 632-5946
Gennum Japan: Shinjuku Green Tower Building 27F 6-14-1, Nishi Shinjuku Shinjuku-ku, Tokyo 160-0023 Japan
Tel: +81 (03) 3349-5501
Fax: +81 (03) 3349-5505
ABSOLUTE MAXIMUM RATINGS
PARAMETER
CAUTION
VALUE/UNITS
Supply Voltage
ELECTROSTATIC
SENSITIVE DEVICES
±13.5 V
0°C ≤ TA ≤ 70°C
Operating Temperature Range
DO NOT OPEN PACKAGES OR HANDLE
EXCEPT AT A STATIC-FREE WORKSTATION
-65°C ≤ TS ≤150°C
Lead Temperature (soldering, 10 seconds)
260°C
Storage Temperature Range
Video Input Voltage
±5 V
Control Input Voltage
±5 V
Video Input Differential Voltage
±5 V
ELECTRICAL CHARACTERISTICS GT4123B
PARAMETER
POWER
SUPPLIES
VS = ±5V, T A = 0°C to 70°C, RL=10kΩ, C L=10pF unless otherwise shown.
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
±4.5
±5
±13.2
V
Supply Voltage
±VS
+ Supply Current
I+
-
15
19.5
mA
- Supply Current
I-
-
15
19.5
mA
Common Mode Input Signal
V IN CM
-
-
2.2
V
Supply Voltage = ±5 V
Positve Excursion Limit
Negative Excursion Limit
Bandwidth
-
-
-3.5
V
10
-
-
MHz
20
25
-
MHz
-
0.01
0.02
%
-
0.01
0.03
deg
60
70
-
dB
-0.02
-0.005
-
dB
-
4
10
ns
ƒ = 1 kHz
70
-
-
dB
ƒ = 10 MHz
25
-
-
dB
V A or B/V O
ƒSIG = 5 MHz (see note 1)
70
75
-
dB
V C/VA or B
ƒSIG = 5 MHz (see note 2)
80
85
-
dB
BW0.05
BW 0.1
Differential Gain
dg
Differential Phase
dp
±0.05 dB, V IN= 150 mVp-p
±0.1 dB, VIN= 150 mVp-p
V IN = 40 IRE, 0V CM
at 3.58 MHz and 4.43 MHz
V IN = 40 IRE, 0V CM
at 3.58 MHz and 4.43 MHz
SIGNAL
PATH
PP Signal / RMS Noise
S/N
V SIG = 1 Vp-p,
Gain
AV
100 kHz (ß = 100%)
Delay
td SIG
PSRR
Power Supply Rejection
Ratio
Off Isolation & Crosstalk
CONTROL
CHANNEL
Output Offset
Channel A or Channel B
-
-
±15
mV
Offset Difference
Channel A - Channel B
0
-
±5
mV
Input Resistance
RIN
Input Capacitance
CIN
Output Resistance
ROUT
Output Capacitance
COUT
Bandwidth
BW0.1
Delay
tD CONT
ƒ=1 MHz
at ±0.1 dB, VIN = 150 mVp-p
Linearity
Control Breakthrough
VC = 0 to 1 V ƒ C =1 to 10 MHz
V C = 0 to 1 V ƒ C = 3.58 MHz
Crossfade Balance
Control Range
NOTE:
ƒ=1 MHz
VC
1. V A or B = +1 Vp-p, output taken from OUTPUT
2 . V C = +1 Vp-p, output taken from VA or VB
521 - 20 - 02
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100
-
-
kΩ
-
2.0
-
pF
-
-
0.50
Ω
-
2.0
-
pF
15
20
-
MHz
-
4
10
ns
-
-
1.5
%
-
-
-35
dB
-15
0
+15
mV
0
-
+1
V
DETAILED DESCRIPTION
The GT4123B is a low power two quadrant video multiplier for
use in a wide range of applications including broadcast and
multimedia.
When VC is less than 0.5 V, VCA reduces and VCB increases in
proportion so that less of Channel A and more of Channel B
signal is transferred. Similarly, when VC is greater than 0.5 V,
the opposite occurs.
The internal topology of the device is shown in Figure 1 below.
The SPAN or control range is internally set so that a CONTROL
voltage of 0 V completely cuts off Channel A and fully turns on
Channel B. Similarly, a CONTROL voltage of 1 V will fully turn
on Channel A and completely turn off Channel B.
IN A
AMP A
COMP
XA
+
VCA
+
Σ1
+
AMP D
OUT
IN B
AMP B
XB
+
VCB = 0.5 - (VC - 0.5)
+
CONTROL
(VC)
AMP C
+
VCB
VCA = 0.5 + (VC - 0.5)
Σ2
+
+
Σ3
+
The linear portion of the transfer characteristic has a linearity
of better than 1.5%.
The outputs from the multipliers are applied to an analog
summing circuit (å1) whose output feeds a wideband amplifier
(Amp D) and presents the mixed signals to the outside world.
The inverting nodes of each input are directly connected to the
output.
0.5V
REF
Fig. 1
There is a small dead band at either end of the CONTROL
input. The amount of dead band is about 100 mV. The
CONTROL input can be preceded by an operational amplifier
to overcome the dead band and level shift the control signal
so that other than 0 to 1 V range can be used. The bandwidth
of the CONTROL input is in the order of 20 MHz at ±0.1 dB to
allow for very fast KEY signals.
Functional Block Diagram of the GT4123B
Each input is applied to a differential amplifier (AMP A and AMP
B). From the amplifiers, the signals are passed to analog
multiplier circuits (XA and XB) whose outputs are the product
of the input signals and internally generated controlling voltages
VCA and VCB.
In this manner, the closed loop gain is nearly unity providing
wideband, stable operation. Because the devices have only 8
pins and require virtually no external parts, the GT4123B lends
itself to high density, multi-function PC board layouts in devices
such as RGB mixers and four layer keyers where close control
law tracking is essential.
The internal control voltages are derived from a unity gain
differential amplifier (AMP C) whose outputs (true and invert)
are the difference between an internal 0.5 V reference voltage,
and the externally applied CONTROL voltage. In addition, the
internal DC offset of 0.5 V is applied to the controlling voltage
summing circuits å2 and å3.
Therefore,
VCA = 0.5 V + (VC - 0.5 V)
and
VCB = 0.5 V - (VC - 0.5 V)
When the control input VC equals 0.5 volts, VCA = 0.5 V and
VCB = 0.5 V, and 50% of each input signal passes to the output
of the multiplier stages.
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521- 20 - 02
+5V
0.1
8
7
+5V
5 - 30pF
4
2
150
FROM
NETWORK
ANALYSER
75
0.1
GT4123B
5
4 CLC110
1
3
6
1
0.1
TO
NETWORK
ANALYSER
8
5
75
10k
0.1
-5V
B
0.1
A
-5V
All resistors in ohms, all capacitors in
microfarads unless otherwise stated
Fig. 2
+1V
Frequency Response, Cross Talk, Differential Gain & Phase Test Circuit
+5V
-5V
0.1
0.1
8
6
6dB AMPLIFIER
VIDEO OUT
GT4123B
VA
5
1
75
7
75
4
3
2
VB
150
75
5-30 pF
VC
All resistors in ohms, all capacitors in
microfarads unless otherwise stated
Fig. 3
(VS = ±5V, unless otherwise specified)
0.2
0
0.1
-20
0
-40
CROSSTALK (dB)
GAIN (dB)
GT4123B TYPICAL PERFORMANCE CURVES
Typical Application Circuit
-0.1
VS = ±12V
-0.2
VS = ±5V
-80
VC - CHANNEL A
-100
-0.3
-120
-0.4
0.1
1
10
1
100
10
100
FREQUENCY (MHz)
FREQUENCY (MHz)
Fig. 4 Frequency Response
521 - 20 - 02
VC - CHANNEL B
-60
Fig. 5 Crosstalk vs Frequency
4 of 5
2.5
0.03
OUTPUT RESISTANCE (ý)
0.02
dg / dp
0.01
0
dg
dp
-0.01
-0.02
2
1.5
1
0.5
0
-0.03
1
10
0.1
FREQUENCY (MHz)
1
10
FREQUENCY (MHz)
Fig. 6 dg & dp vs Frequency
CH-B
Fig. 7 Output Resistance vs Frequency
CH-A
GAIN (%)
100
50
0
-0.2
0.0
0.2
0.4
0.6
0.8
1.0
1.2
CONTROL VOLTAGE (VC)
Fig. 8 Control Characteristics
DOCUMENT
IDENTIFICATION
PRODUCT PROPOSAL
This data has been compiled for market investigation purposes
only, and does not constitute an offer for sale.
ADVANCE INFORMATION NOTE
This product is in a development phase and specifications are
subject to change without notice. Gennum reserves the right to
remove the product at any time. Listing the product does not
constitute an offer for sale.
PRELIMINARY DATA SHEET
The product is in a preproduction phase and specifications are
subject to change without notice.
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 September 1994 Gennum Corporation. All rights reserved. Printed in Canada.
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