Quad, Low Cost, Gain of 1, Video Op Amp Features General Description * * * * * * Optimized for 5V operation Stable at gain of 1 50 MHz Gain bandwidth product 130 V/s slew rate Drives 150 load to video levels Input and outputs operate at negative supply rail * -60 dB isolation at 4.2 MHz The EL2420C operational amplifier, built using Elantec's complementary bipolar process, offers unprecedented high frequency performance at a very low cost. It is suitable for any application, such as consumer video, where traditional DC performance specifications are of secondary importance to the high frequency specifications. On a 5V supply at a gain of +1 the EL2420C will drive a 150 load to +2V, with a bandwidth of 50 MHz. This device achieves 0.1 dB bandwidth at 5 MHz. Applications The recommended power supply voltage is 5V. At zero and 5V supplies, the inputs will operate to ground. When the outputs are at 0V the amplifier draws only 2.4 mA of supply current. * * * * Consumer video amplifier Active filters/integrators Cost sensitive applications Single supply amplifiers EL2420C EL2420C Connection Diagram Ordering Information Part No Temp. Range Package Outline # EL2420CN -40C to +85C 14-Lead P-DIP MDP0031 EL2420CS -40C to +85C 14-Lead SO MDP0027 P-DIP, SO April 1998 Rev B 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. (c) 1997 Elantec, Inc. EL2420C EL2420C Quad, Low Cost, Gain of 1, Video Op Amp Absolute Maximum Ratings (T A Total Supply Voltage Input Voltage Differential Input Voltage Peak Output Current = 25 C) 18V -6VS 6V 75 mA per amplifier Power Dissipation Storage Temperature Range Operating Temperature Range See Curves -65C to +150C -40C to +85C 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, therefor TJ = TC = TA. Test Level Test Procedure I 100% production tested and QA sample tested per QA test plan QCX0002. II 100% production tested at TA = 25C and QA sample tested at TA = 25C, TMAX and TMIN per QA test plan QCX0002. III QA sample tested per QA test plan QCX0002. IV Parameter is guaranteed (but not tested) by Design and Characterization Data. V Parameter is typical value at TA = 25C for information purposes only. DC Characteristics VS=+5V, RL=1K , VIN=1V, TA=25C unless otherwise specified. Parameter Description VOS Input Offset Voltage TCVOS Average Offset Voltage Drift IB Input Bias Current IOS Input Offset Current TCIOS Average Offset Current Drift AVOL Open Loop Gain Conditions Min Typ Max Test Level -20 10 20 I mV V V/C A [1] -50 -15 [1] Units -7 -3 I 0.3 1.0 I A V nA/C -1 -3 VOUT=..5, 2.5, RL= 1K 160 250 I V/V VOUT=..5, 2.5, RL= 150K 160 250 V V/V PSRR Power Supply Rejection Ratio VS = 4.5V to 5.5V 43 50 I dB CMRR Common Mode Rejection Ratio VCM = 0V to +3.8V 55 65 I dB CMIR Common Mode Input Range VOUT Output Voltage Swing RFB = RG = 1K, RL = 150 ISC Output Short Circuit Current Output to Ground IS Supply Current No Load (per channel) VIN = 0V RIN Input Resistance Differential 150 V K Common Mode 1.5 V M 1 V pF 0.150 V V V CIN Input Capacitance ROUT Output Resistance PSOR Power Supply Operating Range 0.0 [2] 2.8 3.2 75 125 2.0 2.4 AV = +1 @ 10 MHz Single Supply 4 1. Measured from TMIN to TMAX. 2. A heat-sink is required to keep junction temperature below absolute maximum when an output is shorted. 2 3.0 I V V 3.0 6 I mA I mA Closed Loop AC Electrical Characteristics VS=5V, AC Test Figure, TA = 25C unless otherwise specified Parameter BW Description -3dB Bandwidth (VOUT = 0.4 mVp-p) 0.1 dB Bandwidth (VOUT = 0.4 mVp-p) Conditions Min Typ Max Test Level Units AV = +1 100 V MHz AV = +1 10 V MHz MHz GBWP Gain Bandwith Product 50 V PM Phase Margin 55 V () SR Slew Rate 85 130 V V/s 8 FBWP Full Power Bandwidth [1] 11 V MHz tR, tF Rise Time, Fall Time 0.1V step 2 V ns OS Overshoot 0.1V step 15 V % tPD Propagation Delay 3.5 V ns ns tS Settling to 0.1% (AV = 1) dG Differential Gain dP Differential Phase eN Input Noise Voltage iN Input Noise Current CS Channel Separation P = 5 MHz [2] [2] VS = 5V, 2V Step 80 V NTSC/PAL 0.1 V % NTSC/PAL 0.2 V () 10 KHz 15 V nV/rt(Hz) 10 KHz 1.5 V nV/rt(Hz) 55 V dB 1. For VS = 5V, VOUT = 4Vpp. Full power bandwidth is based on slew rate measurement using: FPBW = SR/(2pi*Vpeak) 2. Video performance measured at VS = 5V, AV = +2 with 2 times normal video level across RL = 150 3 EL2420C EL2420C Quad, Low Cost, Gain of 1, Video Op Amp EL2420C EL2420C Quad, Low Cost, Gain of 1, Video Op Amp Typical Performance Curves 14-Pin Plastic DIP Maximum Power Dissipation vs Ambient Temperature 14-Lead SO Maximum Power Dissipation vs Ambient Temperature Simplified Block Diagram 4 Applications Information Product Description Single 5 Volt Supply Video Cable Driver The EL2420C operational amplifier is stable at a gain of 1. It is built on Elantec's proprietary complimentary bipolar process. This topology allows it to be used in a variety of applications where current mode amplifiers are not appropriate because of restrictions placed on the feedback elements. This product is especially designed for applications where high bandwidth and good video performance characteristics are desired but the higher cost of more flexible and sophisticated products are prohibitive. These amplifiers may be used as a direct coupled video cable driver with a gain of 2. With a 75 back matching resistor driving a terminated 75 cable the output at the cable load will be original video level (1V NTSC). The best operating mode is with direct coupling. The input signal must be offset to keep the entire signal within the range of the amplifier. The required offset voltage can be set with a resistor divider and a bypass capacitor in the video path (Figure 1). The input DC offset should be between .3V and .5V. With RA=68K and RB=4.7K the input offset will be .32V. Since these amplifiers require a DC load at their outputs it is good design practice to add a 250 resistor to ground directly at the amplifier output. Then if the 75 cable termination resistor were inadvertently removed there would still be an output signal. The values in figure 1 give an output range of 0V to 2.6V Power Supplies The EL2420C is designed to work at a supply voltage difference of 4.5V to 5.5V. It will work on any combination of supplies. All electrical characteristics are measured with a 5V supply. Output Swing vs Load Output capacitive coupling also has some restrictions. These amplifiers require a DC load at their outputs. A 75 back matching resistor to a cable and a 75 load to ground at the end of the cable provide a 150 DC load. But output capacitive coupling opens this DC path so an extra pulldown resistor on the amplifier output to ground is required. Figure 4 shows a 250 resistor. Capacitively coupling the output will require that we shift the output offset voltage higher than in the direct coupled case. Using RA=43K and RB=4.7K will make the quiescent output offset voltage about 1V. The output dynamic range will be .6V to 3V. Please refer to the simplified block diagram. This amplifier provides an NPN pull-up transistor output and a passive 1250 pull-down resistor to the most negative supply. In a application where the load is connected to VS- the output voltage can swing to within 200 mV of VS- . Output Drive Capability This device does not have short circuit protection. Each output is capable of than 100 mA into a shorted output. Care must be used in the design to limit the output current with a series resistor. 5 EL2420C EL2420C Quad, Low Cost, Gain of 1, Video Op Amp Quad, Low Cost, Gain of 1, Video Op Amp 0.1 F 0.32 VB 68K RA CB 4.7K + 0.64 VB AMP V AMP V OUT 1V RO 75 250 75 75 RCL RB RPD V IN RIS 1K 1K + - RG Video 1V RIL RF + - 75 EL2420C EL2420C V1 5V Figure 1. Input capacitive coupling will increase the needed dynamic range of the amplifier. The standard NTSC video signal is 1V peak to peak plus 143 mV for the color AC peak. The video signal is made up of the -286 mV sync pulse plus the 714 mV picture signal which may very from 0V to 714 mV. The video signal average value for a black picture is about 28 mV (Figure 2) and with a white picture level is about 583 mV (Figure 3). This gives a maximum change in average value of about 555 mV. A direct coupled amplifier with an standard NTSC video signal needs a dynamic range of 1.143V. But with input capacitance coupling the dynamic range requirements are the sum of the 1.143V video plus the average picture value change of 0.555V or 1.698VP-P. At a gain of two this doubles to 3.394V. These amplifiers do not have this much dynamic range so a gain of less than 2 must be used to avoid waveform compression under all conditions. Gain = 2 1.428 1.166 1.8 V offset Amp Out Volts 2.062 1.8 0 -0.572 +0.348 +0.062 Y10 53 s 0.714 V 0.6 0.583 V 0.867 0.0 V -0.286 V 1.3 s 3.8 s 5.1 s Figure 2. White Level Video 6 Gain = 2 0.714 V 1.8 V offset Amp Out Volts +3.172 53 mV Average BL +45 mV 0.686 V +28 mV 0.0 V -0.286 V +56 mV +1.8 +1.172 Average Picture Value Change -- 555 mV Figure 3. Black Level Video Printed Circuit Layout Capacitively coupling the input and output is worse than a capacitor only on the input. Without any special compromises you can only take a gain of one. But if the backmatch resistor is reduced to 36, reducing the output range requirement 25% and the output offset is shifted to 2.1V you can take a gain of 1.5 and have a standard NTSC 1Vat the 75 load. The EL2420C is well behaved, and easy to apply in most applications. However, a few simple techniques will help assure rapid, high quality results. As with any high frequency device, good PCB layout is necessary for optimum performance. Ground-plane construction is highly recommended, as is good power supply bypassing. A 0.1 F ceramic capacitor is recommended for bypassing both supplies. Lead lengths should be as short as possible, and bypass capacitors should be as close to the device pins as possible. For good AC performance, parasitic capacitances should be kept to a minimum at both inputs and at the output. Resistor values should be kept under 5 K because of the RC time constants associated with the parasitic capacitance. Metal-film and carbon resistors are both acceptable, use of wire-wound resistors is not recommended because of their parasitic inductance. Similarly, capacitors should be low-inductance for best performance. A simple transistor, capacitor and resistor sync tip clamp may be used when the input is already AC coupled to set the sync tip to ground.This gives the input a fixed DC level and can be used like a direct coupled input. The clamp uses a PNP transistor with the collector at ground and the base has a 200 K resistor to 5V. The emitterconnects to the amplifier input and a capacitor from the video input. The clamp functions as an inverted Beta current source for input bias current with plus inputs and a clamp to ground for minus inputs. The R A and RB resistors are removed for the clamp option (Figure 4). 7 EL2420C EL2420C Quad, Low Cost, Gain of 1, Video Op Amp Quad, Low Cost, Gain of 1, Video Op Amp 2N3904 200K PNP Clamp Option RC 12K RA 1.4VB V AMP RO + - RG 2K RIL 75 RF + Video - 1V Figure 4. 8 5V V1 RPD 250 - 1K 75 36 47 F V OUT 1V CO RCL 2.1VB 75 AMP RB V IN + 4.7K CI CB 0.1 F 47 F RIS EL2420C EL2420C 9 EL2420C EL2420C Quad, Low Cost, Gain of 1, Video Op Amp EL2420C EL2420C Quad, Low Cost, Gain of 1, Video Op Amp 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. April 1998 Rev B WARNING - 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 10 Printed in U.S.A.