52038DOC

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Document No. 520 - 38 - 3 GT4123, GT4123A Two Channel Video Multipliers 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, Mi yamae Villa ge, 2–10–42 Miyamae, Suginami –ku Tokyo 168, Japan tel. (03) 3334-7700 fax (03) 3247-8839 DATA SHEET

DESCRIPTION

The GT4123 and GT4123A are monolithic dual-channel video multipliers for use in a wide range of applications including broadcast and multimedia. Featuring two wideband video inputs and a single control input, they achieve high quality video mixing of the 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 to 1V with respect to the ground pin, and V A and V B are the video input signals. The GT4123 operates with typical power supply voltages of ± 10 volts and draws 15 mA of current. The GT4123A typically operates from +12 and -5 volt supplies. Both are available in 8 pin PDIP and 8 pin SOIC. An Application Note entitled "Using the GT4123 and GT4123A Video MIxer ICs" (Document No. 520 - 61) is available from Gennum Corporation.

FEATURES

  • two-quadrant video multiplication
  • 20 MHz 0.1 dB video & control channel bandwidth
  • one external frequency compensation adjustment
  • ultra low differential gain & differential phase
  • convenient 8 pin package

APPLICATIONS

  • Multimedia Graphics Overlay
  • Production switchers
  • Linear Keyers Vcc VIDEO IN A VIDEO IN B OUTPUT FREQ. COMP CONTROL GROUND

8 PIN DIP

Part Number Package Type Temperature Range GT4123 - CDA 8 pin PDIP 0 o to 70o C GT4123 - CKA 8 pin SOIC 0 o to 70o C GT4123ACDA 8 pin PDIP 0 o to 70o C GT4123ACKA 8 pin SOIC 0 o to 70o C

ORDERING INFORMATION

VREF (0.5V) (INTERNAL) FREQ COMP VIDEO IN B CONTROL MULTIPLIER CORE FUNCTIONAL BLOCK DIAGRAM CAUTION ELECTROSTATIC SENSITIVE DEVICES DO NOT OPEN PACKAGES OR HANDLE EXCEPT AT A STATIC-FREE WORKSTATION Revision Date: January 1994.

ELECTRICAL CHARACTERISTICS GT4123 Supply Voltage V S Operating Range ± 9 ± 10 ± 12 V + Supply Current I+ - 15 19.5 mA - Supply Current I- - 13 17.0 mA Common Mode Input Signal V IN CM -- 5 V Bandwidth BW 0.1 at ± 0.1 dB V IN = 150 mVp-p 20 25 - MHz Bandwidth BW 3 at -3 dB V IN = 1 Vp-p - 80 - MHz Frequency Response DC -10 MHz - ± 0.05 - dB Differential Gain ∂gV IN = 40 IRE at 3.58 MHz - 0.01 0.05 % Differential Phase ∂pV IN = 40 IRE at 3.58 MHz - 0.01 0.05 degrees Signal to Noise S/N V SIG = 1 V, BW = 5 MHz 64 70 - dB Gain A VL 100 kHz (ß = 100%) -0.02 -0.005 - dB Delay t d SIG -4 1 0n s 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 Input Resistance R IN ƒ=1 MHz 150 - - k Ω Input Capacitance C IN - 2.0 - pF Output Resistance R OUT ƒ=1 MHz (see Figure 9) - - 0.1 Ω Output Capacitance C OUT - 2.0 - pF Bandwidth BW 0.1 at ± 0.1 dB V IN = 150 mVp-p 20 25 - MHz Bandwidth BW 3 at -3 dB V IN = 1 Vp-p - 80 - MHz Delay t D CONT -4 1 0n s Linearity 10% to 90% range - 1 - % 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 - 5 10 mVp-p Control Range V C (see Figure 10) 0 - +1 V PARAMETER VALUE Supply Voltage (VS) ± 13.5 V Operating Temperature Range 0 ° C ≤ TA ≤ 70° C Storage Temperature Range -65 ° C ≤ TS ≤ 150° C Lead Temperature (Soldering, 10 Sec) 260° C Video Input Voltage (VA,VB) to ground ± 5 V Control Input Voltage (VC) to ground ± 5 V Video Input Differential Voltage (VA - VB) ± 5 V ABSOLUTE MAXIMUM RATINGS PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS POWER SUPPLIES SIGNAL CHANNEL CONTROL CHANNEL VS = ± 10V, T A = 0°C to 70 °C, RL=10kΩ 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

ELECTRICAL CHARACTERISTICS GT4123A Supply Voltage V S Operating Range +9 +12 ± 12 V -3 -5 + Supply Current I+ - 15 19.5 mA - Supply Current I- - 13 17.0 mA Common Mode Input Signal V IN CM -- 5 V Bandwidth BW 0.1 at ± 0.1 dB V IN = 150 mVp-p 20 25 - MHz Bandwidth BW 3 at -3 dB V IN = 1 Vp-p - 80 - MHz Frequency Response DC -10 MHz - ± 0.05 - dB Differential Gain ∂gV IN = 40 IRE at 3.58 MHz - 0.02 0.05 % Differential Phase ∂pV IN = 40 IRE at 3.58 MHz - 0.02 0.05 degrees Signal to Noise S/N V SIG = 1 V, BW = 5 MHz 64 70 - dB Gain A VL 100 kHz (ß = 100%) -0.02 -0.005 - dB Delay t d SIG -4 1 0n s 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 Input Resistance R IN ƒ=1MHz 150 - - k Ω Input Capacitance C IN - 2.0 - pF Output Resistance R OUT ƒ=1MHz (see Figure 9) - - 0.1 Ω Output Capacitance C OUT - 2.0 - pF Bandwidth BW 0.1 at ± 0.1 dB V IN = 150 mVp-p 20 25 - MHz Bandwidth BW 3 at -3 dB V IN = 1 Vp-p - 80 - MHz Delay t D CONT -4 1 0n s Linearity 10% to 90% range - 1 - % 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 - 5 10 mVp-p Control Range V C (see Figure 10) 0 - +1 V PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS POWER SUPPLIES SIGNAL CHANNEL VS = ± 12V, -5V, T A = 0 °C to 70 °C, RL=10k Ω unless otherwise shown. CONTROL CHANNEL 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 GT4123 and GT4123A are the first dedicated single device, two input video mixer ICs available to the professional video and multimedia markets. The internal topology of the devices is shown in Figure 1. Fig. 1 Functional Block Diagram of the GT4123 and GT4123A Each input signal is applied to a conventional differential amplifier (AMP A and AMP B). From the amplifiers, the signals are applied 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. These voltages are derived from a unity gain differential amplifier (AMP C) whose outputs (true and invert) are the difference between an externally applied CONTROL voltage C) and an internal 0.5 volt reference voltage. In addition, the internal DC offset of 0.5 volts is applied to the controlling voltage summing circuits Σ2 and Σ3. Therefore, V CA = 0.5V + (VC - 0.5V) and VCB = 0.5V - (VC - 0.5V) When the CONTROL input (V C) equals 0.5 volts, V CA and VCB = 0.5 volts and exactly 50% of each input signal passes to the output of the multiplier stages. When VC is less than 0.5 volts, VCA reduces and VCB increases in proportion so that less of the Channel A signal and more of the Channel B signal is transferred. Similarly, when V C is greater than 0.5 volts, the opposite occurs. The SPAN or control range is internally set so that a CONTROL voltage of 0 volts completely cuts off Channel A and fully turns on Channel B. Similarly, a CONTROL voltage of 1 volt will fully turn on Channel A and completely turn Channel B off. Figure 10 shows the CONTROL transfer characteristics of the GT4123 and GT4123A. There is a small ‘dead band’ at either extreme of the CONTROL input. The amount of ‘dead band’ is about 100 mV and is shown in Figure 10. The CONTROL input can be preceded by an operational amplifier so biased as to overcome this ‘dead band’ as well as level shift the control signal so that other than 0 to 1 volt ranges can be used. The bandwidth of the CONTROL input is sufficient to allow very fast keying and is in the order of 20 MHz at -0.1 dB. The linear portion of the transfer characteristic has a linearity of 1% or better. The outputs from the multipliers are applied to an analog summing circuit (Σ1) whose output feeds a wideband amplifier (Amp D) and presents the mixed signals to the outside world. The inverting inputs of each input amplifier 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 in order to function, they lend themselves to high density, multi-functional PC board layouts. Several devices can be used in parallel applications such as R-G-B mixers and four-layer keyers where close control law tracking is essential. The only difference between the GT4123 and the GT4123A is the fact that the latter device can operate with non-equal power supplies. The negative supply can be as low as -3 volts unlike the GT4123 which can only operate down to ± 9 volt supplies. COMP VCB OUT AMP B IN A IN B CONTROL (VC) AMP D AMP C XB XA AMP A 0.5V REF VCA

0.1 +10V -10V 0.1 +5V 0.1 0.1 -5V TO NETWORK ANALYSER CLC110 0.1 10k DUT FROM NETWORK ANALYSER GT4123 / GT4123A TEST CIRCUITS VSIG = 1VP-P + 0.5V BIAS (100 kHz to 10 MHz) Fig. 2 Crossfade Balance +10V 0.1 VA VB VC 680 0.1 -10V 5-30 pF (-5V)(+12V) 6dB AMPLIFIER VIDEO OUT GT4123 (GT4123A) 4 3 2 Fig. 4 Typical Application Circuit All resistors in ohms, all capacitors in µF unlesss otherwise stated. Fig. 3 Frequency Response, Crosstalk & Differential Gain & Phase All resistors in ohms, all capacitors in µF unlesss otherwise stated. FROM NETWORK ANALYSER 0.1 5 - 30pF 680 B +5V +10V 0.1 A 10k 0.1 -5V +1V -10V TO NETWORK ANALYSER CLC110 0.1 0.1 DUT All resistors in ohms, all capacitors in µF unlesss otherwise stated.

-20 -30 -40 -50 -60 -70 -80 -90 -100 1 10 1 1001 1001 10 100 FREQUENCY (MHz) dB Fig. 6 Crosstalk vs Frequency 0.03 0.02 0.01 0.00 -0.01 -0.02 -0.03 dg / dp 1 3 5 10 FREQUENCY (MHz) 0.1 1 10 FREQUENCY (MHz) Fig. 7 Differential Gain & Phase vs Frequency Fig. 8 Crossfade Balance vs Frequency dg dp CH-A CH-B CH-A VIN=1Vp-p CH-BVIN = 150mVp-p R COMP = 680Ω C COMP = 18pF VC = 1Vp-p+0.5VDC REF = 1Vp-p (0dB) dB 0.5 0.4 0.3 0.2 0.1 0.0 -0.1 -0.2 -0.3 -0.4 -0.5 dB 01 100.01 0.1 1.0 10 FREQUENCY (MHz) 1.0 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0 RESISTANCE (Ω ) CH-B CH-A CONTROL VOLTAGE (VC) Fig. 10 Control Characteristics 1 10 100 FREQUENCY (MHz) Fig. 9 Output Resistance vs Frequency Fig. 5 Frequency Response 100 GAIN (%) -30 -35 -40 -45 -50 -55 -60 TYPICAL PERFORMANCE CURVES FOR GT4123 / GT4123A

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. 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. Revision Notes: Detailed Description added.