EL4094C EL4094C Video Gain Control/Fader Features General Description # Complete video fader # 0.02%/0.04§ differential gain/ phase @ 100% gain # Output amplifier included # Calibrated linear gain control # g 5V to g 15V operation # 60 MHz bandwidth # Low thermal errors The EL4094C is a complete two-input fader. It combines two inputs according to the equation: Applications # # # # # Video faders/wipers Gain control Video text insertion Level adjust Modulation VOUT e VINA (0.5V a Vg) a VINB (0.5V b Vg), where VGAIN is the difference between VGAIN and VGAIN pin voltages and ranges from b 0.5V to a 0.5V. It has a wide 60 MHz bandwidth at b 3 dB, and is designed for excellent video distortion performance. The EL4094C is the same circuit as the EL4095, but with feedback resistors included on-chip to implement unity-gain connection. An output buffer is included in both circuits. The gain-control input is also very fast, with a 20 MHz smallsignal bandwidth and 70 ns recovery time from overdrive. The EL4094C is compatible with power supplies from g 5V to g 15V, and is available in both the 8-pin plastic DIP and SO-8. Ordering Information Part No. Temp. Range Package OutlineÝ Connection Diagram EL4094CN b 40§ C to a 85§ C 8-Pin P-DIP MDP0031 EL4094CS b 40§ C to a 85§ C 8-Pin SO MDP0027 Manufactured under U.S. Patent No. 5,321,371, 5,374,898 Note: All information contained in this data sheet has been carefully checked and is believed to be accurate as of the date of publication; however, this data sheet cannot be a ‘‘controlled document’’. Current revisions, if any, to these specifications are maintained at the factory and are available upon your request. We recommend checking the revision level before finalization of your design documentation. © 1993 Elantec, Inc. August 1996, Rev D 4094 – 1 EL4094C Video Gain Control/Fader Voltage between VS a and GND Voltage between VS a and VSb Input Voltage VS a VS VINA, VINB VGAIN VGAIN a 18V a 33V (VSb) b0.3V to (VS a ) a 0.3V Input Voltage Input Voltage IOUT Output Current Internal Power Dissipation TA Operating Ambient Temp. Range TJ Operating Junction Temperature TST Storage Temperature Range VGAIN g 5V VSb to VS a g 35 mA See Curves b 40§ C to a 85§ C 150§ C b 65§ C to a 150§ C TD is 0.6in Absolute Maximum Ratings (TA e 25§ C) Important Note: All parameters having Min/Max specifications are guaranteed. The Test Level column indicates the specific device testing actually performed during production and Quality inspection. Elantec performs most electrical tests using modern high-speed automatic test equipment, specifically the LTX77 Series system. Unless otherwise noted, all tests are pulsed tests, therefore TJ e TC e TA. Test Level I II III IV V Test Procedure 100% production tested and QA sample tested per QA test plan QCX0002. 100% production tested at TA e 25§ C and QA sample tested at TA e 25§ C , TMAX and TMIN per QA test plan QCX0002. QA sample tested per QA test plan QCX0002. Parameter is guaranteed (but not tested) by Design and Characterization Data. Parameter is typical value at TA e 25§ C for information purposes only. Open Loop DC Electrical Characteristics Parameter Limits Description Min VOS Input Offset Voltage IB a VIN Input Bias Current PSRR Power Supply Rejection Ratio EG Gain Error, 100% Setting 60 Max Test Level Units Typ 4 30 I mV 2 10 I mA I dB b 0.8 I % (V a ) b2.5 I V (V a ) b2.5 I V 150 I mA 80 b 0.5 VIN VIN Range (Vb) a 2.5 VO Output Voltage Swing (Vb) a 2.5 ISC Output Short-Circuit Current VGAIN, 100% Minimum Voltage at VGAIN for 100% Gain VGAIN, 0% Maximum Voltage at VGAIN for 0% Gain NL, Gain 50 95 0.45 0.5 0.55 I V b 0.55 b 0.5 b 0.45 I V Gain Control Non-linearity, VIN e g 0.5V 1.5 4 I % NL, AV e 1 AV e 0.5 AV e 0.25 Signal Non-linearity, VIN e 0 to g 1V, VGAIN e 0.55V Signal Non-linearity, VIN e 0 to g 1V, VGAIN e 0V Signal Non-linearity, VIN e 0 to g 1V, VGAIN e b0.25V 0.01 0.05 0.2 0.5 V V I % % % RGAIN Resistance between VGAIN and VGAIN 4.6 5.5 6.6 I kX IS Supply Current 12 14.5 19 I mA FT Off-Channel Feedthrough b 75 b 50 I dB 2 TD is 3.3in VS e g 5V, TA e 25§ C, VGAIN e a 0.6V to measure channel A, VGAIN e b0.6V to measure channel B, VGAIN e 0V, unless otherwise specified EL4094C Video Gain Control/Fader Closed Loop AC Electrical Characteristics Parameter Limits Description Min Typ Max Test Level Units SR Slew Rate; VOUT from b3V to a 3V measured at b2V and a 2V 370 500 V V/ms BW Bandwidth, b3 dB b 1 dB b 0.1 dB 45 60 35 6 III V V MHz MHz MHz dG Differential Gain, AC amplitude of 286 mVp-p at 3.58 MHz on DC offset of b0.7, 0, and a 0.7V AV e 100% AV e 50% AV e 25% 0.02 0.20 0.40 V V V % % % Differential Phase, AC ampitude of 286 mVp-p at 3.58 MHz on DC offset of b0.7, 0, and a 0.7V AV e 100% AV e 50% AV e 25% 0.04 0.20 0.20 V V V (§ ) (§ ) (§ ) di BW, GAIN b 3 dB Gain Control Bandwidth, VGAIN Amplitude 0.5 Vp-p 20 V MHz TREC, GAIN Gain Control Recovery from Overload; VGAIN from b0.6V to 0V 70 V ns Typical Performance Curves Small-Signal Step Response for Gain e 100%, 50%, 25%, and 0%. VS g 5V Large-Signal Step Response for Gain e 100%, 50%, 25%, and 0%. VS g 12V 4094 – 2 4094 – 3 3 TD is 2.6in VS e g 15V, CL e 15 pF, TA e 25§ C, AV e 100% unless otherwise noted EL4094C Video Gain Control/Fader Typical Performance Curves Ð Contd. Frequency Response vs Capacitive Loading Frequency Response vs Resistive Loading Frequency Response vs Gain Off-Channel Isolation Over Frequency Change in Slewrate and Bandwidth with Supply Voltage Output Noise Over Frequency 4094 – 4 4 EL4094C Video Gain Control/Fader Typical Performance Curves Ð Contd. Change in 100% Gain Error, Supply Current, Slewrate and Bandwidth over Temperature Nonlinearity vs VIN for Gain e 100%, 75%, 50% and 25% Differential Gain Error vs Voffset for Gain e 100%, 75%, 50% and 25%. F e 3.58 MHz Differential Phase Error vs Voffset for Gain e 100%, 75%, 50% and 25%. F e 3.58 MHz Differential Gain Error vs Voffset for Gain e 100%, 75%, 50% and 25%. F e 3.58 MHz Differential Phase Error vs Voffset for Gain e 100%, 75%, 50% and 25%. F e 3.58 MHz 4094 – 5 5 EL4094C Video Gain Control/Fader Typical Performance Curves Ð Contd. Differential Gain and Phase Error vs Gain Differential Gain and Phase Error vs Gain 4094 – 6 Gain vs VG. 1VDC at VINA Cross-Fade Balance. VINA e VINB e 0V 4094 – 7 4094 – 8 Gain Control Response to a Non-Overloading Step, Constant Sinewave at VINA VGAIN Overload Recovery Response 4094 – 10 4094 – 9 6 EL4094C Video Gain Control/Fader Typical Performance Curves Ð Contd. Gain Control Gain vs Frequency Change in V(100%) and V(0%) of Gain Control vs /VG Offset Change in V(100%) and V(0%) of Gain Control vs Supply Voltage Change in V(100%) and V(0%) of Gain Control vs Die Temperature Supply Current vs Supply Voltage Maximum Dissipation vs Ambient Temperature 4094 – 11 7 EL4094C Video Gain Control/Fader it is necessary to overdrive the gain control input by 30 mV or more. This would set the gain control voltage range as b 0.565V to a 0.565V, or 30 mV beyond the maximum guaranteed 0% to 100% range. In fact, the gain control inputs are very complex. Here is a representation of the terminals: Applications Information The EL4094 is a self-contained and calibrated fader subsystem. When a given channel has 100% gain the circuit behaves as a current-feedback amplifier in unity-gain connection. As such, video and transfer distortions are very low. As the gain of the input is reduced, a 2-quadrant multiplier is gradually introduced into the signal path and distortions increase with reducing gain. The input impedance also changes with gain setting, from about 1 MX at 100% gain down to 16 kX at zero gain. To maximize gain accuracy and linearity, the inputs should be driven from source impedances of 500X or less. Linearity 4094 – 12 Representation of Gain Control Inputs VG and /VG The EL4094 is designed to work linearly with g 2V inputs, but lowest distortion occurs at g 1V levels and below. Errors are closer to those of a good current-feedback amplifier above 90% gain. For gain control inputs between g 0.5V ( g 90 mA), the diode bridge is a low impedance and all of the current into Vg flows back out through/Vg. When gain control inputs exceed this amount, the bridge becomes a high impedance as some of the diodes shut off, and the Vg impedance rises sharply from the nominal 5.5KX to about 500KX. This is the condition of gain control overdrive. The actual circuit produces a much sharper overdrive characteristic than does the simple diode bridge of this representation. Low-frequency linearity is 0.1% or better for gains 25% to 100% and inputs up to 1V. NTSC differential gain and phase errors are better than 0.3% and 0.3§ for the 25% to 100% gain range. These distortions are not strongly affected by supply voltage nor output loading, at least down to 150X. For settling to 0.1%, however, it is best to not load the output heavily and to run the EL4094 on the lowest practical supply voltages, so that thermal effects are minimized. The gain input has a 20 MHz b 3 dB bandwidth and 17 ns risetime for inputs to g 0.45V. When the gain control voltage exceeds the 0% or 100% values, a 70 ns overdrive recovery transient will occur when it is brought back to linear range. If quicker gain overdrive response is required, the Force control inputs of the EL4095 can be used. Gain Control Inputs The gain control inputs are differential and may be biased at any voltage as long as /VGAIN is less than 2.5V below V a and 3V above V b . The differential input impedance is 5.5 kX, and the common-mode impedance is more than 500 kX. With zero differential voltage on the gain inputs, both signal inputs have a 50% gain factor. Nominal calibration sets the 100% gain of VINA input at a 0.5V of gain control voltage, and 0% at b 0.5V of gain control. VINB’s gain is complementary to that of VINA; a 0.5V of gain control sets 0% gain at VINB and b 0.5V gain control sets 100% VINB gain. The gain control does not have a completely abrupt transition at the 0% and 100% points. There is about 10 mV of ‘‘soft’’ transfer at the gain endpoints. To obtain the most accurate 100% gain factor or best attenuation at 0% gain, Output Loading The EL4094 does not work well with heavy capacitive loads. Like all amplifier outputs, the output impedance becomes inductive over frequency resonating with a capacitive load. The effective output inductance of the EL4094 is about 350 nH. More than 50 pF will cause excessive frequency response peaking and transient ringing. The problem can be solved by inserting a lowvalue resistor in series with the load, 22X or more. If a series resistance cannot be used, then adding a 300X or less load resistor to ground or a ‘‘snubber’’ network may help. A snubber is a re8 EL4094C Video Gain Control/Fader perature. The EL4094 thus cannot be operated with g 15V supplies at 75§ C in the surface-mount package; the supplies should be reduced to g 5V to g 12V levels, especially if extra dissipation occurs when driving a load. Applications Information Ð Contd. sistor in series with a capacitor, 150X and 100 pF being typical values. The advantage of a snubber is that it does not draw DC load current. Unterminated coaxial line loads can also cause resonances, and they should be terminated either at the far end or a series back-match resistor installed between the EL4094 and the cable. The EL4094 as a Level Adjust A common use for gain controls is as an input signal levellerÐa circuit that scales too-large or too-small signals to a standard amplitude. A typical situation would be to scale a variable video input by a 6 dB to b 6 dB to obtain a standard amplitude. The EL4094 cannot provide more than 0 dB gain, but it can span the range of 0 dB to b 12 dB with another amplifier gaining the output up by 6 dB. The simplest way to obtain the range is to simply ground the B input and vary the gain of the signal applied to the A input. The disadvantage of this approach is that linearity degrades at low gains. By connecting the signal to the A input of the EL4094 and the signal attenuated by 12 dB to the B input, the gain control offers the highest linearity possible at 0 dB and b 12 dB extremes, and good performance between. The circuit is shown on the following page. The output stage can deliver up to 140 mA into a short-circuit load, but it is only rated for a continuous 35 mA. More continuous current can cause reliability problems with the on-chip metal interconnect. Video levels and loads cause no problems at all. Noise The EL4094 has a very simple noise characteristic: the output noise is constant (40 nV/ SHz wideband) for all gain settings. The input-referred noise is then the output noise divided by the gain. For instance, at a gain of 50% the input noise is 40 nV/ SHz/0.5, or 80 nV/ SHz. Bypassing The EL4095 can be used to provide the required gains without the extra amplifier. In practice, the gain control is adjusted to set a standard video level regardless of the input level. The EL4583 sync-separator has a recovered amplitude output that can be used to servo the gain control voltage. Here is the curve of differential gain and phase distortion for varying inputs, with the output set to standard video level: The EL4094 is fairly tolerant of power-supply bypassing, but best multiplier performance is obtained with closely connected 0.1 mF ceramic capacitors. The leaded chip capacitors are good, but neither additional tantalums nor chip components are necessary. The signal inputs can oscillate locally when connected to long lines or unterminated cables. Power Dissipation Peak die temperature must not exceed 150§ C. At this temperature, the epoxy begins to soften and becomes unstable, chemically and mechanically. This allows 75§ C internal temperature rise for a 75§ C ambient. The EL4094 in the 8-pin PDIP package has a thermal resistance of 87§ /W, and can thus dissipate 862 mW at a 75§ C ambient temperature. The device draws 17 mA maximum supply current, only 510 mW at g 15V supplies, and the circuit has no dissipation problems in this package. The SO-8 surface-mount package has a 153§ /W thermal resistance with the EL4094, and only 490 mW can be dissipated at 75§ C ambient tem- 4094 – 14 Differential Gain and Phase of Linearized Level Control 9 EL4094C Video Gain Control/Fader For an adjustable preemphasis filter, for instance, filter A might be an all-pass filter to compensate for the delay of filter B, a peaking filter. Fading the gain from A to B provides a variable amount of peaking, but constant delay. Applications Information Ð Contd. The differential gain error is kept to 0.3% and the differential phase to 0.15§ or better over the entire input range. The EL4094 as an Adjustable Filter The EL4094 as a Phase Modulator Equalizers are used to adjust the delay or frequency response of systems. A typical use is to compensate for the high-frequency loss of a cable system ahead of the cable so as to create a flat response at the far end. A generalized scheme with the EL4094 is shown below. To make a phase modulator, filter A might be a leading-phase network, and filter B a lagging network. The wide bandwidth of the gain-control input allows wideband phase modulation of the carrier applied to the main input. Of course, the carrier and gain inputs must not be digital but be reasonably clean sinewaves for the modulation to be accurate. 4094 – 13 a 6 dB to b 6 dB Linearized Level Control 4094 – 15 General Adjustable Equalizer 10 This macromodel is offered to allow simulation of general EL4094 behavior. We have included these characteristics: Small-signal frequency response Output loading effects Input impedance Off-channel feedthrough Output impedance over frequency Signal path DC distortions VGAIN I-V characteristics VGAIN overdrive recovery delay 100% gain error These will give a good range of results for various operating conditions, but the macromodel does not behave identically as the circuit in these areas: Temperature effects Signal overload effects Signal and /VG operating range Current-limit Video and high-frequency distortions Supply voltage effects Slewrate limitations Noise Power supply interactions The macromodel’s netlist is based on the Pspice simulator (copywritten by the Microsim Company). Other simulators may not support the POLY function, which is used to implement multiplication as well as square-low nonlinearities. ****** ****** * * * * * * .subckt EL4094subckt *** VINB l l l l l VOUT l l l l /VG l l l VG l l VINA (1 4 6 7 8) l 11 TAB WIDE ROL 810 0 290k Ccomp 810 0 3.5p G1 10 0 810 0 b10 ROUT 10 0 0.1 LOUT 10 4 350.200n RLOUT 10 4 80 r1 10 910 10 c1 910 911 300p r2 911 0 90 *** *** Input channel A *** RINA 22 910 16k ra 11 0 1k Cfeedthrougha 23 8 130p Rfeedthrougha 8 22 1.0 Ela 23 22 1 0 1.0 Rspice3 23 22 1E12 G1a 11 0 POLY(1) (22, 910) 0.0 0.001 b3Eb6 G2a 810 0 POLY(2) (11,0) (13, 0) 0.0 0.0 0.0 0.0 0.001 *** ***Input channel B *** RINB 25 910 16k rb 20 0 1k Cfeedthroughb 24 1 130p Rfeedthroughb 1 25 1.0 E1b 24 25 8 0 1.0 Rspice4 24 25 1E12 G1b 20 0 POLY(1) (25, 910) 0.0 0.001 b3Eb6 G2b 810 0 POLY(2) (20,0) (19, 0) 0.0 0.0 0.0 0.0 0.001 *** ***Gain control *** Rspice1 13 0 1E12 Rspice2 18 0 1E12 R10 14 0 1E7 C10 14 0 8Eb16 D1 14 15 Dclamp D2 16 14 Dclamp .model Dclamp D (TT e 200n) V1 15 0 4999.3 V2 0 16 4999.3 V3 13 17 0.5 V4 19 18 0.5 G10 14 0 7 6 b0.001 G11 7 6 14 0 b2Eb8 E10 17 0 14 0 1Eb4 E11 18 0 14 0 b1Eb4 *** .ends ****** EL4094C Macromodel TD is 6.8in TD is 1.3in Video Gain Control/Fader TAB WIDE EL4094C EL4094C EL4094C Video Gain Control/Fader EL4094C Macromodel Ð Contd. 4094 – 16 EL4094 Macromodel Schematic General Disclaimer Specifications contained in this data sheet are in effect as of the publication date shown. Elantec, Inc. reserves the right to make changes in the circuitry or specifications contained herein at any time without notice. Elantec, Inc. assumes no responsibility for the use of any circuits described herein and makes no representations that they are free from patent infringement. August 1996, Rev D WARNING Ð Life Support Policy Elantec, Inc. products are not authorized for and should not be used within Life Support Systems without the specific written consent of Elantec, Inc. Life Support systems are equipment intended to support or sustain life and whose failure to perform when properly used in accordance with instructions provided can be reasonably expected to result in significant personal injury or death. Users contemplating application of Elantec, Inc. products in Life Support Systems are requested to contact Elantec, Inc. factory headquarters to establish suitable terms & conditions for these applications. Elantec, Inc.’s warranty is limited to replacement of defective components and does not cover injury to persons or property or other consequential damages. Elantec, Inc. 1996 Tarob Court Milpitas, CA 95035 Telephone: (408) 945-1323 (800) 333-6314 Fax: (408) 945-9305 European Office: 44-71-482-4596 12 Printed in U.S.A.