GT4123B GENNUM | Alldatasheet
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Document No. 521 - 20 - 02 GT4123B Two Channel Video Multiplier
DESCRIPTION
The GT4123B is a monolithic dual-channel video multiplier for use in a wide range of applications including broadcast and multimedia. 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: V O = [ ( V C • VA) + (1 - V C) VB ] where VC is the control input voltage, which may be varied continuously over the range 0 V to 1 V, and V A and VB are the video input signals. 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.
FEATURES
/i157 two-quadrant video multiplication /i157 operation from ±4.5 V to ±13.2 V supply voltages /i157 20 MHz ±0.1 dB video & control channel bandwidth /i157 ultra low differential gain & differential phase /i157 convenient 8 pin package /i157 Pb-free and Green
ORDERING INFORMATION
FREQ. COMP FUNCTIONAL BLOCK DIAGRAM VIDEO IN A OUTPUT VREF (0.5V) (INTERNAL) FREQ COMP VIDEO IN B CONTROL MULTIPLIER CORE GT4123B PIN CONNECTIONS DATA SHEET
APPLICATIONS
Multimedia Graphics Overlay Production Switchers Linear Keyers OUTPUT GROUND VIDEO IN B VIDEO IN A VEE Part Package Temperature Pb-Free Number Type Range 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 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) 334 9-5501 Fax: +81 (03) 3349-5505 Revision date: July 2004
ELECTRICAL CHARACTERISTICS GT4123B Supply Voltage ±V S ±4.5 ±5 ±13.2 V + Supply Current I+ - 15 19.5 mA - Supply Current I- - 15 19.5 mA Common Mode Input Signal V IN CM Supply Voltage = ±5 V Positve Excursion Limit - - 2.2 V Negative Excursion Limit - - -3.5 V Bandwidth BW 0.05 ±0.05 dB, V IN= 150 mVp-p 10 - - MHz BW0.1 ±0.1 dB, V IN= 150 mVp-p 20 25 - MHz Differential Gain /c100 gV IN = 40 IRE, 0V CM - 0.01 0.02 % at 3.58 MHz and 4.43 MHz Differential Phase /c100 pV IN = 40 IRE, 0V CM - 0.01 0.03 deg at 3.58 MHz and 4.43 MHz PP Signal / RMS Noise S/N V SIG = 1 Vp-p, 60 70 - dB Gain A V 100 kHz (ß = 100%) -0.02 -0.005 - dB Delay t d SIG -4 1 0n s Power Supply Rejection PSRR ƒ = 1 kHz 70 - - dB Ratio ƒ = 10 MHz 25 - - dB Off Isolation & Crosstalk V A or B /VO ƒSIG = 5 MHz (see note 1) 70 75 - dB VC/VA or B ƒSIG = 5 MHz (see note 2) 80 85 - dB Output Offset Channel A or Channel B - - ±15 mV Offset Difference Channel A - Channel B 0 - ±5 mV Input Resistance R IN ƒ=1 MHz 100 - - k Ω Input Capacitance C IN - 2.0 - pF Output Resistance R OUT ƒ=1 MHz - - 0.50 Ω Output Capacitance C OUT - 2.0 - pF Bandwidth BW 0.1 at ±0.1 dB, V IN = 150 mVp-p 15 20 - MHz Delay t D CONT -4 1 0n s Linearity - - 1.5 % Control Breakthrough V C = 0 to 1 V ƒ C =1 to 10 MHz - - -35 dB Crossfade Balance V C = 0 to 1 V ƒ C = 3.58 MHz -15 0 +15 mV Control Range V C 0- + 1V PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS POWER SUPPLIES SIGNAL PATH CONTROL CHANNEL ABSOLUTE MAXIMUM RATINGS PARAMETER VALUE/UNITS Supply Voltage ±13.5 V Operating Temperature Range 0°C ≤ TA ≤ 70°C Storage Temperature Range -65°C ≤ TS ≤150°C Lead Temperature (soldering, 10 seconds) 260°C Video Input Voltage ±5 V Control Input Voltage ±5 V Video Input Differential Voltage ±5 V CAUTION ELECTROSTATIC SENSITIVE DEVICES DO NOT OPEN PACKAGES OR HANDLE EXCEPT AT A STATIC-FREE WORKSTATION VS = ±5V, T A = 0°C to 70°C, R L=10kΩ , CL=10pF unless otherwise shown. NOTE: 1. VA or B = +1 Vp-p, output taken from OUTPUT 2 . VC = +1 Vp-p, output taken from V A or VB
The GT4123B is a low power two quadrant video multiplier for use in a wide range of applications including broadcast and multimedia. The internal topology of the device is shown in Figure 1 below. Fig. 1 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 V CA and VCB. 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 /c229 2 and /c229 3. Therefore, V CA = 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. 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 V C is greater than 0.5 V, the opposite occurs. 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. 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. 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 ( /c229 1) 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. 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. COMP VCB OUT AMP B IN A IN B CONTROL (VC) AMP D AMP C XB XA AMP A 0.5V REF VCA
-20 -40 -60 -80 -100 -120 FROM NETWORK ANALYSER 0.1 5 - 30pF 150 B +5V +5V 0.1 A 10k 0.1 -5V +1V -5V TO NETWORK ANALYSER CLC110 0.1 0.1 GT4123B 0.1 1 10 100 0.2 0.1 -0.1 -0.2 -0.3 -0.4 GAIN (dB) FREQUENCY (MHz) Fig. 4 Frequency Response 1 10 100 FREQUENCY (MHz) Fig. 5 Crosstalk vs Frequency VS = ±12V VS = ±5V VC - CHANNEL B VC - CHANNEL A All resistors in ohms, all capacitors in microfarads unless otherwise stated Fig. 2 Frequency Response, Cross Talk, Differential Gain & Phase Test Circuit +5V 0.1 VA VB VC 150 0.1 -5V 5-30 pF 6dB AMPLIFIER VIDEO OUT GT4123B 4 3 2 All resistors in ohms, all capacitors in microfarads unless otherwise stated Fig. 3 Typical Application Circuit GT4123B TYPICAL PERFORMANCE CURVES (VS = ±5V, unless otherwise specified) CROSSTALK (dB)
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. dg / dp 1 10 FREQUENCY (MHz) Fig. 6 dg & dp vs Frequency dg dp 0.03 0.02 0.01 -0.01 -0.02 -0.03 0.1 1 10 2.5 1.5 0.5 Fig. 7 Output Resistance vs Frequency FREQUENCY (MHz) OUTPUT RESISTANCE (ý) 100 CONTROL VOLTAGE (VC) CH-B CH-A Fig. 8 Control Characteristics GAIN (%)