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| EL2090C EL2090C 100 MHz DC-Restored Video Amplifier Features Complete video level restoration system 0 01% differential gain and 0 02 differential phase accuracy at NTSC 100 MHz bandwidth 0 1 dB flatness to 20 MHz Sample-and-hold has 15 nA typical leakage and 1 5 pC charge injection System can acquire DC correction level in 10 ms or 5 scan lines of 2 ms each to IRE VS e g5V to g15V TTL CMOS hold signal General Description The EL2090C is the first complete DC-restored monolithic video amplifier sub-system It contains a very high-quality video amplifier and a nulling sample-and-hold amplifier specifically designed to stabilize video performance When the HOLD logic input is set to a logic 0 during a horizontal sync the sampleand-hold amplifier may be used as a general-purpose op-amp to null the DC offset of the video amplifier When the HOLD input goes to a logic 1 the sample-and-hold stores the correction voltage on the hold capacitor to maintain DC correction during the subsequent scan line The video amplifier is optimized for video characteristics and performance at NTSC is nearly perfect It is a current-feedback amplifier so that b 3 dB bandwidth changes little at various closed-loop gains The amplifier easily drives video signal levels into 75X loads With 100 MHz bandwidth the EL2090 is also useful in HDTV applications The sample-and-hold is optimized for fast sync pulse response The application circuit shown will restore the video DC level in five scan lines even if the HOLD pulse is only 2 ms long The output impedance of the sample-and-hold is low and constant over frequency and load current so that the performance of the video amplifier is not compromised by connections to the DC restore circuitry The EL2090C is fabricated in Elantec's proprietary Complementary Bipolar process which produces NPN and PNP transistors with equivalent AC and DC performance The EL2090C is specified for operation over the 0 C to 75 C temperature range Applications Input amplifier in video equipment Restoration amplifier in video mixers Ordering Information Part No Temp Range Pkg Outline EL2090CN 0 C to a 75 C 14-Pin P-DIP MDP0031 EL2090CM 0 C to a 75 C 16-Lead SOL MDP0027 Connection Diagrams 14-Pin DIP Package 16-Pin SOL Package January 1996 Rev D 2090 - 1 2090 - 2 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 Patent pending CMS 2090DS 1990 Elantec Inc EL2090C 100 MHz DC-Restored Video Amplifier Absolute Maximum Ratings (TA e 25 C) Voltage between V a and Vb Voltage between VIN a S HIN a S HINb CHOLD and GND pins VOUT Current Current into VINb and HOLD Pins 36V (V a ) a 0 5V to (Vb) b0 5V 60 mA 5 mA Current S HOUT Internal Power Dissipation Operating Ambient Temperature Range Operating Junction Temperature Plastic DIP or SOL Storage Temperature Range 16 mA See Curves 0 C to 75 C 150 C b 65 C to a 150 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 VS e g15V RL e 150X TA e 25 C unless otherwise specified Parameter IS Description Total Supply Current Temp Full Min Typ 14 Max 17 Test Level II Units mA Video Amplifier Section (Not Restored) VOS IB a IBb ROL AVOL VO Input Offset Voltage a VIN Input Bias Current b VIN Input Bias Current Full Full Full 25 C Full Full Full 25 C 56 8 2 30 300 65 70 15 150 II II II V II II II II mV mA mA V mA dB V V mA Transimpedance Open-Loop Voltage Gain VOUT e g2V Output Voltage Swing VS e g15V RL e 2 kX VS e g5V RL e 150X Short-Circuit Current a VIN Set to g2V b VIN to Ground through 1 kX g12 g3 0 g13 g3 5 ISC g50 g90 g160 Sample-And-Hold Section VOS IB IOS RIN DIFF RIN COMM VCM Input Offset Voltage Input Bias Current Input Offset Current Input Differential Resistance Input Common-Mode Resistance Common-Mode Input Range Full Full Full 25 C 25 C Full g11 2 05 0 05 200 100 g12 5 10 25 05 II II II V V II mV mA mA TD is 3 9in kX MX V 2 EL2090C 100 MHz DC-Restored Video Amplifier Open Loop DC Electrical Characteristics VS e g15V RL e 150X TA e 25 C unless otherwise specified Parameter Sample-And-Hold Section AVOL CMRR PSRR Vthresh Idroop Icharge VO ISC Description Temp Contd Min Typ Max Test Level Units Contd Full Full Full Full Full Full Full 25 C g90 Large Signal Voltage Gain Common-Mode Rejection Ratio VCM e g11V Power-Supply Rejection Ratio VS e g5V to g15V HOLD Pin Logic Threshold Hold Mode Droop Current Charge Current Available to Chold Output Swing RL e 2k Short-Circuit Current 15k 75 75 08 50k 95 95 14 10 g135 II II II 20 50 II II II II g40 VV dB dB V nA mA V mA TD is 2 3in TD is 3 4in g10 g10 g13 g17 II Closed Loop AC Electrical Characteristics VS e g15V CL e 15 pF Cstray (bVIN) e 2 5 pF RF e RG e 300X RL e 150X Chold e 100 pF TA e 25 C Parameter Video Amplifier Section SR BW SlewRate VOUT from b2 to a 2V Bandwidth b 3 dB g1 dB g0 1 dB Description Min Typ Max Test Level Units 600 75 35 10 100 60 20 V III III III V ms MHz MHz MHz Peaking dG Differential Gain VIN from b0 7V to 0 7V F e 3 58 MHz Differential Phase VIN from b0 7V to 0 7V F e 3 58 MHz 0 01 V % di 0 02 V Sample-And-Hold Section BW DQ DT Ts Gain-Bandwidth Product Sample to Hold Charge Injection (Note 1) Sample to Hold or Hold to Sample Delay Time Sample to Hold Settling Time to 2 mV 13 15 20 200 5 V III V V MHz pC ns ns Note 1 The logic input is between 0V and 5V with a 220X resistor in series with the HOLD pin and 39 pF capacitor from HOLD pin to ground 3 EL2090C 100 MHz DC-Restored Video Amplifier 2090 - 3 Figure 1 Typical Application (AV e a 2) Typical Performance Curves Relative Frequency Response for Various Gains Frequency Response with Different Loads (AV e a 2) 2090 - 4 Frequency Response Flatness for Various Load and Supply Conditions Frequency Response Flatness vs CIN b AV e a 2 2090 - 5 4 EL2090C 100 MHz DC-Restored Video Amplifier Typical Performance Curves Contd Differential Gain and Phase vs Supply Voltage AV e a 2 RL e 150X VIN from 0 to a 0 7 VDC Deviation from Linear Phase vs Frequency Differential Gain vs DC Input Offset AV e a 2 FO e 3 58 MHz RL e 150X Differential Phase vs DC Input Offset AV e a 2 FO e 3 58 MHz RL e 150X 2090 - 12 Differential Gain vs DC Input Offset AV e a 2 and FO e 30 MHz RL e 150X Differential Phase vs DC Input Offset AV e a 2 FO e 30 MHz RL e 150X 2090 - 6 5 EL2090C 100 MHz DC-Restored Video Amplifier Typical Performance Curves Contd S H Available Charge Current vs Temperature 2090 - 7 Sample-to-Hold Change Injection vs Temperature Typical Droop Current vs Temperature VS e g15V Supply Current vs Supply Voltage Supply Current vs Temperature VS e g15V 2090 - 8 2090 - 9 6 EL2090C 100 MHz DC-Restored Video Amplifier Typical Performance Curves Maximum Power Dissipation vs Ambient Temperature 14-Pin PDIP and 16-Pin SOL Contd This suggests that the largest applicable power supply voltages be used so that the output swing of the sample-and-hold can still correct for the variations of DC offset in the video input with large values of Raz The typical application circuit shown will allow correction of g1V inputs with good isolation of the sample-and-hold output Good isolation is defined as no video degradation due to the insertion of the sample-andhold loop Lower supply voltages will require a smaller value of DC feedback resistor to retain correction of the full input DC variation The EL2090 differential phase performance is optimum at g9V supplies and differential gain only marginally improves above this voltage Since all video characteristics mildly degrade with increasing die temperature the g9V levels are somewhat better than g15V supplies However g15V supplies are quite usable Ultimate video performance especially in HDTV applications can also be optimized by setting the black-level reference such that the signal span at the video amplifier's output is set to its optimum range For instance setting the span to g1V of output is preferable to a span of 0V to a 2V The curves of differential gain and phase versus input DC offset will serve as guides The DC feedback resistor may be split so that a bypass capacitor is added to reduce the initially small sample-and-hold transients to even smaller levels The corruption can be reduced to as low as 1 mV peak seen at the video amplifier output The size of the capacitor should not be so large as to de-stabilize the sample-and-hold feedback loop nor so small as to reduce the video amplifier's gain flatness A resistor or some other video isolation network should be inserted between the video amplifier output and the sample-and-hold input to prevent excessive video from bleeding through the autozero section as well as preventing spurious DC correction due to video signals confusing the sample-and-hold during autozero events Figure 1 shows convenient component values A full 3 58 MHz trap is not necessary for suppressing NTSC chroma burst interaction with the sample-and-hold input the simple R-C network suggested in Figure 1 suffices 2090 - 10 Applications Information The EL2090C is a general purpose component and thus the video amplifier and sample-andhold pins are uncommitted Therefore much of the ultimate performance as a DC-restored video amplifier will be set by external component values and parasitics Some application considerations will be offered here The DC feedback from the sample-and-hold can be applied to either positive or negative inputs of the video amplifier (with appropriate phasing of the sample-and-hold amplifier inputs) We will consider feedback to the inverting video input During a sample mode (the HOLD input at a logic low) the sample-and-hold acts as a simple nulling op-amp Ideally the DC feedback resistor Raz is a high value so as not to couple a large amount of the AC signal on the video input back to the sampleand-hold amplifier output The sample-and-hold output is a low impedance at high frequencies but variations of the DC operating point will change the output impedance somewhat No more than a few ohms output impedance change will occur but this can cause gain variations in the 0 01% realm This DC-dependent gain change is in fact a differential gain effect Some small differential phase error will also be added The best approach is to maximize the DC feedback resistor value so as to isolate the sampleand-hold from the video path as much as possible Values of 1 kX or above for Raz will cause little to no video degradation 7 EL2090C 100 MHz DC-Restored Video Amplifier Applications Information Contd The HOLD input to the sample-and-hold has a 1 4V threshold and is clamped to a diode below ground and 6V above ground The hold step characteristics are not sensitive to logic high nor low levels (within TTL or CMOS swings) but logic slewrates greater than 1000V ms can couple noise and hold step into the sample-to-hold output waveforms The logic slewrate should be greater than 50V ms to avoid hold jitter To avoid artificially high droop in hold mode the Chold pin and Chold itself should be guarded with circuit board traces connected to the output of the sample-and-hold Low-leakage hold capacitors should be used such as mica or mylar but not ceramic The excellent properties of more expensive polystyrene polypropylene or teflon capacitors are not needed hold step and increasing Chold is the most direct way to do this Increasing Chold also reduces the slew rate of the sample and hold section but because of the limited size of the video signal this is usually not a limitation 2 A sampling interval (dictated by the HOLD pin) that is too small By small we mean less than 2 ms For a sampling interval that is wide enough there is enough time for the loop to close and for the amplifier to discharge whatever charge was dumped onto Chold it during the initial power spike and to then ramp up (or down) to the voltage that is proper for a balanced loop When the sampling interval is too small there is insufficient time for internal devices to recover from their initial saturated state from power-up because the feedback is not closed long enough Therefore typical recovery times for the loop are 2 ms or greater Summarizing the two things that could prevent proper saturation recovery are (as mentioned above) too large a capacitor which slows the charge and discharge rate of the stored voltage at Chold and too small a sampling interval in which the entire feedback loop is closed The circuit shown below prevents the fault condition from occurring by preventing the node from ever saturating By clamping the value of Chold to some value lower than the supply voltage less The user should be aware of a combination of conditions that may make the EL2090 operate incorrectly upon power-up The fault condition can be described by noticing that the sample-andhold output (pin 11) appears locked at a voltage close to VCC This voltage is maintained regardless of changes at the inputs to the sample-andhold (pins 5 and 6) or to the HOLD control input (pin 7) Two conditions must occur to bring this about 1 A large value of Chold usually values of 1000 pF or more This is not an unusual situation Many users want to reduce the size of the 2090 - 13 8 EL2090C 100 MHz DC-Restored Video Amplifier Contd a saturation voltage we prevent this node from approaching the positive rail The maximum voltage is set by the resistive voltage divider (between V a and GND) R1 and R2 plus a diode This value can be adjusted if the maximum size of the input signal is known The diode used is an off-the-shelf 1N914 or 1N916 As is true of all 100 MHz amplifiers good bypassing of the supplies to ground is mandatory 1 mF tantalums are sufficient and 0 01 mF leaded chip capacitors in parallel with medium value electrolytics are also good Leads longer than can induce a characteristic 150 MHz resonance and ringing The VIN b of the video amplifier should have the absolute minimum of parasitic capacitance Stray capacitance of more than 3 pF will cause peaking and compromise the gain flatness The bandwidth of the amplifier is fundamentally set by the value of Rf As demonstrated by the frequen- Applications Information cy response versus gain graph the peaking and bandwidth is a weak function of gain The EL2090 was designed for Rf e 300X giving optimum gain flatness at Av e a 2 Unity-gain response is flattest for Rf e 360X gains of a 5 can use Rf e 270X In situations where the peaking is accentuated by load capacitance or b input capacitance the value of Rf will have to be increased and some bandwidth will be sacrificed The VIN a of the video amplifier should not look into an inductive source impedance If the source is physically remote and a terminated input line is not provided it may be necessary to connect an input ``snubber'' to ground A snubber is a resistor in series with a capacitor which de-Q's the input resonance Typical values are 100X and 30 pF The output of the video amplifier is sensitive to capacitive loads greater than 25 pF and a snubber to ground or a resistor in series with the output is useful to isolate reactive loads 9 EL2090C 100 MHz DC-Restored Video Amplifier EL2090 Macromodel Revision A October 1992 param vclamp e b0 002 (TEMPb25) Connections Vidin a Vidinb l l l l l l l l l l subckt EL2090 EL 3 Video Amplifier e1 20 0 3 0 1 0 vis 20 34 0V h2 34 38 vxx 1 0 r10 1 36 25 l1 36 38 20nH iinp 3 0 10mA iinm 1 0 5mA h1 21 0 vis 600 r2 21 22 1K d1 22 0 dclamp d2 0 22 dclamp e2 23 0 22 0 0 00166666666 l5 23 24 0 7mH c5 24 0 0 5pF r5 24 0 600 g1 0 25 24 0 1 0 rol 25 0 400K cdp 25 0 7 7pF q1 12 25 26 qp q2 14 25 27 qn q3 14 26 28 qn q4 12 27 29 qp r7 28 13 4 r8 29 13 4 ios1 14 26 2 5mA ios2 27 12 2 5mA ips 14 12 7 2mA ivos 0 33 5mA vxx 33 0 0V r11 33 0 1K l l l l l l l l l 1 a Vsupply l l l l l l l l 14 b Vsupply l l l l l l l 12 Vid Out l l l l l l 13 S H In a S H Inb l S H Out l l l l l 5 l l l 6 l l l 11 Sample Hold Control Chold l l 7 Hold l 9 g40 49 0 5 6 1e-3 vcur 49 42 0v r43 6 0 100Meg r44 5 0 100Meg r40 42 0 4K d41 50 42 diode d42 42 51 diode v41 50 0 vclamp v42 0 51 vclamp g41 44 0 42 0 200e-6 r42 44 0 31Meg d45 9 14 diode d46 12 9 diode s1 44 9 48 0 swa e40 46 0 9 0 0 95 i40 0 9 10nA r45 46 47 70 l40 47 11 70nH c40 7 9 0 32pF r47 7 48 10K c41 48 0 3pF Models model qn npn(is e 5e-15 bf e 500 tf e 0 1nS) model qp pnp(is e 5e-15 bf e 500 tf e 0 1nS) model dclamp d(is e 1e-30 ibv e 0 02 bv e 2 75 n e 4) model diode d model swa vswitch(von e 1 2v voff e 1 6v roff e 1e12 ron e 100) ends 10 TD is 6 6in EL2090C 100 MHz DC-Restored Video Amplifier EL2090 Macromodel Contd 2090 - 15 Sample and Hold Amplifier 11 EL2090C EL2090C 100 MHz DC-Restored Video Amplifier EL2090 Macromodel Contd 2090 - 14 Video Amplifier 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 WARNING Life Support Policy January 1996 Rev D 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 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 Printed in U S A |
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