LMH6714/6720/6722 Wideband Video Op Amp; Single, Single with Shutdown and Quad General Description Features The LMH6714/6720/6722 series combine National’s VIP10™ high speed complementary bipolar process with National’s current feedback topology to produce a very high speed op amp. These amplifiers provide a 400MHz small signal bandwidth at a gain of +2V/V and a 1800V/µs slew rate while consuming only 5.6mA from ± 5V supplies. 400MHz (AV = +2V/V, VOUT = 500mVPP) −3dB BW 250MHz (AV = +2V/V, VOUT = 2VPP) -3dB BW 0.1dB gain flatness to 120MHz Low power: 5.6mA TTL compatible shutdown pin (LMH6720) Very low diff. gain, phase: 0.01%, 0.01˚ (LMH6714) −58 HD2/ −70 HD3 at 20MHz Fast slew rate: 1800V/µs Low shutdown current: 500uA (LMH6720) 11ns turn on time (LMH6720) 7ns shutdown time (LMH6720) Unity gain stable Improved replacement for CLC400,401,402,404,406 and 446 (LMH6714) n Improved replacement for CLC405 (LMH6720) n Improved replacement for CLC415 (LMH6722) The LMH6714/6720/6722 series offer exceptional video performance with its 0.01% and 0.01˚ differential gain and phase errors for NTSC and PAL video signals while driving a back terminated 75Ω load. They also offer a flat gain response of 0.1dB to 120MHz. Additionally, they can deliver 70mA continuous output current. This level of performance makes them an ideal op amp for broadcast quality video systems. The LMH6714/6720/6722’s small packages (SOIC & SOT23), low power requirement, low noise and distortion allow the LMH6714/6720/6722 to serve portable RF applications. The high impedance state during shutdown makes the LMH6720 suitable for use in multiplexing multiple high speed signals onto a shared transmission line. The LMH6720 is also ideal for portable applications where current draw can be reduced with the shutdown function. Non-Inverting Small Signal Frequency Response n n n n n n n n n n n n n Applications n n n n n n HDTV, NTSC & PAL video systems Video switching and distribution Wideband active filters Cable drivers High speed multiplexer (LMH6720) Programmable gain amplifier (LMH6720) Differential Gain and Phase vs. Number of Video Loads (LMH6714) 20056506 20056528 © 2003 National Semiconductor Corporation DS200565 www.national.com LMH6714/6720/6722 Wideband Video Op Amp; Single, Single with Shutdown and Quad March 2003 LMH6714/6720/6722 Absolute Maximum Ratings Storage Temperature Range (Note 1) Shutdown Pin Voltage (Note 5) If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. Thermal Resistance 2000V Machine Model Package 200V VCC IOUT Common Mode Input Voltage Differential Input Voltage Maximum Junction Temperature Storage Temperature Range (θJA) ± 6.75V 5-Pin SOT23 232˚C/W (Note 3) 6-Pin SOT23 198˚C/W ± VCC 8-Pin SOIC 145˚C/W 2.2V 14-Pin SOIC +150˚C −65˚C to +150˚C Lead Temperature (soldering 10 sec) +VCC to VCC/2-1V Operating Ratings (Note 3) ESD Tolerance (Note 4) Human Body Model −65˚C to +150˚C 130˚C/W Operating Temperature −40˚C +85˚C Nominal Supply Voltage ± 5V ± 6V +300˚C Electrical Characteristics Unless specified, AV = +2, RF = 300Ω: VCC = ± 5V, RL = 100Ω, LMH6714/6720/6722. Boldface limits apply at temperature extremes. Symbol Parameter Conditions Min Typ Max Units Frequency Domain Response SSBW −3dB Bandwidth VOUT = 0.5VPP 345 400 MHz LSBW −3dB Bandwidth VOUT = 2.0VPP 200 250 MHz Gain Flatness VOUT = 2VPP dB GFP Peaking DC to 120MHz 0.1 GFR Rolloff DC to 120MHz 0.1 dB LPD Linear Phase Deviation DC to 120MHz 0.5 deg DG Differential Gain RL = 150Ω, 4.43MHz (LMH6714) 0.01 % DG Differential Gain RL = 150Ω, 4.43MHz (LMH6720) 0.02 % DP Differential Phase RL = 150Ω, 4.43MHz 0.01 deg .5V Step 1.5 ns 2V Step 2.6 ns 12 ns 1800 V/µs Time Domain Response TRS Rise and Fall Time TRL ts Settling Time to 0.05% 2V Step SR Slew Rate 6V Step 1200 Distortion and Noise Response HD2 2nd Harmonic Distortion 2VPP, 20MHz −58 dBc HD3 3rd Harmonic Distortion 2VPP, 20MHz −70 dBc IMD 3rd Order Intermodulation Products 10MHz, POUT = 0dBm −78 dBc > 1MHz > 1MHz > 1MHz 3.4 nV/ 10 pA/ 1.2 pA/ Equivalent Input Noise VN Non-Inverting Voltage NICN Inverting Current ICN Non-Inverting Current Static, DC Performance VIO DVIO IBN ± 0.2 Output Offset Voltage Average Drift Input Bias Current DIBN www.national.com ±6 ±8 8 Non-Inverting Average Drift ±1 4 2 mV µV/˚C ± 10 ± 15 µA nA/˚C (Continued) Unless specified, AV = +2, RF = 300Ω: VCC = ± 5V, RL = 100Ω, LMH6714/6720/6722. Boldface limits apply at temperature extremes. Symbol IBI DIBI Parameter Input Bias Current Conditions Min Inverting Average Drift Typ Max Units −4 ± 12 ± 20 µA 41 nA/˚C PSRR Power Supply Rejection Ratio DC 48 47 58 dB CMRR Common Mode Rejection Ratio DC 48 45 54 dB ICC Supply Current RL = ∞ 4.5 3 5.6 7.5 8 mA ICCI Supply Current During Shutdown LMH6720 500 670 µA Miscellaneous Performance RIN Input Resistance Non-Inverting 2 MΩ CIN Input Capacitance Non-Inverting 1.0 pF ROUT Output Resistance Closed Loop 0.06 Ω VO Output Voltage Range RL = ∞ ± 3.9 V ± 3.8 V ± 2.2 V VOL CMIR ± 3.5 ± 3.4 ± 3.6 ± 3.4 RL = 100Ω Input Voltage Range Common Mode IO Output Current (Note 3) VIN = 0V, Max Linear Current OFFMAX Voltage for Shutdown LMH6720 ONMIN Voltage for Turn On LMH6720 2.0 IIH Current Turn On LMH6720, SD = 2.0V −20 −30 2 20 30 −100 50 70 mA 0.8 V V µA IIL Current Shutdown LMH6720, SD = .8V −600 −400 IOZ ROUT Shutdown LMH6720, SD = .8V 0.2 1.8 MΩ µA ton Turn on Time LMH6720 11 ns toff Turn off Time LMH6720 7 ns Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is intended to be functional, but specific performance is not guaranteed. For guaranteed specifications, see the Electrical Characteristics tables. Note 2: Electrical Table values apply only for factory testing conditions at the temperature indicated. Factory testing conditions result in very limited self-heating of the device such that TJ = TA. No guarantee of parametric performance is indicated in the electrical tables under conditions of internal self heating where TJ > TA. See Applications Section for information on temperature derating of this device." Min/Max ratings are based on product characterization and simulation. Individual parameters are tested as noted. Note 3: The maximum output current (IOUT) is determined by device power dissipation limitations. See the Power Dissipation section of the Application Division for more details. Note 4: Human body model, 1.5kΩ in series with 100pF. Machine model, 0Ω In series with 200pF. Note 5: The shutdown pin is designed to work between 0 and VCC with split supplies (VCC = -VEE). With single supplies (VEE = ground) the shutdown pin should not be taken below VCC/2. 3 www.national.com LMH6714/6720/6722 Electrical Characteristics LMH6714/6720/6722 Connection Diagrams 5-Pin SOT23 (LMH6714) 6-Pin SOT23 (LMH6720) 20056531 Top View 14-Pin SOIC (LMH6722) 20056532 Top View 20056534 Top View 8-Pin SOIC (LMH6714) 8-Pin SOIC (LMH6720) 20056538 20056539 Top View Top View Ordering Information Package 5-Pin SOT23 8-Pin SOIC 6-Pin SOT23 8-Pin SOIC 14-Pin SOIC www.national.com Part Number LMH6714MF LMH6714MFX LMH6714MA LMH6714MAX LMH6720MF LMH6720MFX LMH6720MA LMH6720MAX LMH6722MA LMH6722MAX Package Marking Transport Media 1k Units Tape and Reel A95A 3k Units Tape and Reel 95 Units/Rail LMH6714MA 2.5k Units Tape and Reel 1k Units Tape and Reel A96A 3k Units Tape and Reel 95 Units/Rail LMH6720MA 2.5k Units Tape and Reel 55 Units/Rail LMH6722MA 2.5 Units Tape and Reel 4 NSC Drawing MF05A M08A MF06A M08A M14A (AV = 2, RF = 300Ω, RL = 100Ω Unless Specified). Non-Inverting Small Signal Frequency Response Non-Inverting Large Signal Frequency Response 20056506 20056507 Inverting Frequency Response Non-Inverting Frequency Response vs. VO 20056503 20056508 Inverting Frequency Response vs. VO Harmonic Distortion vs. Frequency 20056509 20056504 5 www.national.com LMH6714/6720/6722 Typical Performance Characteristics LMH6714/6720/6722 Typical Performance Characteristics (AV = 2, RF = 300Ω, RL = 100Ω Unless Specified). (Continued) 2nd Harmonic Distortion vs. VOUT 3rd Harmonic Distortion vs. VOUT 20056502 20056501 DG/DP (LMH6714) DG/DP (LMH6720) 20056528 20056505 DG/DP (LMH6722) Large Signal Pulse Response 20056513 20056535 www.national.com 6 LMH6714/6720/6722 Typical Performance Characteristics (AV = 2, RF = 300Ω, RL = 100Ω Unless Specified). (Continued) Small Signal Pulse Response Closed Loop Output Resistance 20056511 20056510 Open Loop Transimpedance Z(s) PSRR vs. Frequency 20056523 20056516 CMRR vs. Frequency Frequency Response vs. RF 20056512 20056525 7 www.national.com LMH6714/6720/6722 Typical Performance Characteristics (AV = 2, RF = 300Ω, RL = 100Ω Unless Specified). (Continued) DC Errors vs. Temperature Maximum VOUT vs. Frequency 20056518 20056526 Crosstalk vs. Frequency (LMH6722) for each channel with all others active 3rd Order Intermodulation vs. Output Power 20056527 www.national.com 20056536 8 LMH6714/6720/6722 Application Section FEEDBACK RESISTOR SELECTION One of the key benefits of a current feedback operational amplifier is the ability to maintain optimum frequency response independent of gain by using appropriate values for the feedback resistor (RF). The Electrical Characteristics and Typical Performance plots specify an RF of 300Ω, a gain of +2V/V and ± 5V power supplies (unless otherwise specified). Generally, lowering RF from it’s recommended value will peak the frequency response and extend the bandwidth while increasing the value of RF will cause the frequency response to roll off faster. Reducing the value of RF too far below it’s recommended value will cause overshoot, ringing and, eventually, oscillation. 20056515 FIGURE 2. RF vs. Non-Inverting Gain In the “RF vs. Non-Inverting Gain” and the “RF vs. Inverting Gain” charts the recommended value of RF is depicted by the solid line, which starts high, decreases to 200Ω and begins increasing again. The reason that a higher RF is required at higher gains is the need to keep RG from decreasing too far below the output impedance of the input buffer. For the LMH6714/6720/6722 the output resistance of the input buffer is approximately 180Ω and 50Ω is a practical lower limit for RG. Due to the limitations on RG the LMH6714/ 6720/6722 begins to operate in a gain bandwidth limited fashion for gains of ± 5V/V or greater. 20056512 FIGURE 1. Frequency Response vs. RF The plot labeled "Frequency Response vs. RF" shows the LMH6714/6720/6722’s frequency response as RF is varied (RL = 100Ω, AV = +2). This plot shows that an RF of 147Ω results in peaking. An RF of 300Ω gives near maximal bandwidth and gain flatness with good stability. An RF of 400Ω gives excellent stability with only a small bandwidth penalty. Since all applications are slightly different it is worth some experimentation to find the optimal RF for a given circuit. Note that it is not possible to use a current feedback amplifier with the output shorted directly to the inverting input. The buffer configuration of the LMH6714/6720/6722 requires a 600Ω feedback resistor for stable operation. For more information see Application Note OA-13 which describes the relationship between RF and closed-loop frequency response for current feedback operational amplifiers. The value for the inverting input impedance for the LMH6714/6720/6722 is approximately 180Ω. The LMH6714/ 6720/6722 is designed for optimum performance at gains of +1 to +6 V/V and −1 to −5V/V. When using gains of ± 7V/V or more the low values of RG required will make inverting input impedances very low. When configuring the LMH6714/6720/6722 for gains other than +2V/V, it is usually necessary to adjust the value of the feedback resistor. The two plots labeled “RF vs. Noninverting Gain” and “RF vs. Inverting Gain” provide recommended feedback resistor values for a number of gain selections. 20056514 FIGURE 3. RF vs. Inverting Gain ACTIVE FILTERS When using any current feedback Operational Amplifier as an active filter it is important to be very careful when using reactive components in the feedback loop. Anything that reduces the impedance of the negative feedback, especially at higher frequencies, will almost certainly cause stability problems. Likewise capacitance on the inverting input needs 9 www.national.com LMH6714/6720/6722 Application Section (Continued) to be avoided. See Application Notes OA-7 and OA-26 for more information on Active Filter applications for Current Feedback Op Amps. 20056524 FIGURE 5. Typical Application with Suggested Supply Bypassing 20056521 FIGURE 4. Enable/Disable Operation LAYOUT CONSIDERATIONS Whenever questions about layout arise, use the evaluation board as a guide. The following Evaluation boards are available with sample parts: ENABLE/DISABLE OPERATION USING ± 5V SUPPLIES (LMH6720 ONLY) The LMH6720 has a TTL logic compatible disable function. Apply a logic low ( < .8V) to the DS pin and the LMH6720 is disabled. Apply a logic high ( > 2.0V), or let the pin float and the LMH6720 is enabled. Voltage, not current, at the Disable pin determines the enable/disable state. Care must be exercised to prevent the disable pin voltage from going more than .8V below the midpoint of the supply voltages (0V with split supplies, VCC/2 with single supplies) doing so could cause transistor Q1 to Zener resulting in damage to the disable circuit. The core amplifier is unaffected by this, but disable operation could become slower as a result. Disabled, the LMH6720 inputs and output become high impedances. While disabled the LMH6720 quiescent current is approximately 500µA. Because of the pull up resistor on the disable circuit the ICC and IEE currents are not balanced in the disabled state. The positive supply current (ICC) is approximately 500µA while the negative supply current (IEE) is only 200µA. The remaining IEE current of 300µA flows through the disable pin. The disable function can be used to create analog switches or multiplexers. Implement a single analog switch with one LMH6720 positioned between an input and output. Create an analog multiplexer with several LMH6720’s. The LMH6720 is at it’s best at a gain of 1 for multiplexer applications because there is no RG to shunt signals to ground. LMH6714 LMH6720 LMH6722 CLC730216 CLC730227 SOT CLC730216 SOIC CLC730227 SOIC CLC730231 To reduce parasitic capacitances, the ground plane should be removed near the input and output pins. To reduce series inductance, trace lengths of components in the feedback loop should be minimized. For long signal paths controlled impedance lines should be used, along with impedance matching at both ends. Bypass capacitors should be placed as close to the device as possible. Bypass capacitors from each rail to ground are applied in pairs. The larger electrolytic bypass capacitors can be located anywhere on the board, the smaller ceramic capacitors should be placed as close to the device as possible. In addition Figure 2 shows a capacitor (C1) across the supplies with no connection to ground. This capacitor is optional, however it is required for best 2nd Harmonic suppression. If this capacitor is omitted C2 and C3 should be increased to .1µF each. VIDEO PERFORMANCE The LMH6714/6720/6722 has been designed to provide excellent performance with both PAL and NTSC composite video signals. Performance degrades as the loading is increased, therefore best performance will be obtained with back terminated loads. The back termination reduces reflections from the transmission line and effectively masks capacitance from the amplifier output stage. While all parts offer excellent video performance the LMH6714 and LMH6722 are slightly better than the LMH6720. DISABLE LIMITATIONS (LMH6720 ONLY) The feedback Resistor (RF) limits off isolation in inverting gain configurations. During shutdown the impedance of the LMH6720 inputs and output become very high ( > 1MΩ), however RF and RG are the dominant factor for effective output impedance. Do not apply voltages greater than +VCC or less than 0V (VCC/2 single supply) to the disable pin. The input ESD diodes will also conduct if the signal leakage through the feedback resistors brings the inverting input near either supply rail. www.national.com SOT SOIC 10 LMH6714/6720/6722 Application Section (Continued) WIDE BAND DIGITAL PROGRAMMABLE GAIN AMPLIFIER (LMH6720 ONLY) 20056519 FIGURE 6. Wideband Digitally Controlled Programmable Gain Amplifier Channel Switching 20056520 FIGURE 7. PGA Output As shown in Figure 6 and Figure 7 the LMH6720 can be used to construct a digitally controlled programmable gain amplifier. Each amplifier is configured to provide a digitally selectable gain. To provide for accurate gain settings, 1% or better tolerance is recommended on the feedback and gain resistors. The gain provided by each digital code is arbitrary through selection of the feedback and gain resistor values. in the feedback loop to equalize the incoming signal. The RC networks peak the signal at higher frequencies. This peaking is a piecewise linear approximation of the inverse of the frequency response of the coaxial cable. Figure 9 shows the effect of this equalization on a digital signal that has passed through 150 meters of coaxial cable. Figure 10 shows a Bode plot of the frequency response of the circuit in Figure 8 along with equations needed to design the pole and zero frequencies. Figure 11 shows a network analyzer plot of an LMH6714/6720/6722 with the following component values: RG = 309Ω R1 = 450Ω C1 = 470pF R2 = 91Ω C2 = 68pF AMPLITUDE EQUALIZATION Sending signals over coaxial cable greater than 50 meters in length will attenuate high frequency signal components much more than lower frequency components. An equalizer can be made to pre emphasize the higher frequency components so that the final signal has less distortion. This process can be done at either end of the cable. The circuit in Figure 8 shows a receiver with some additional components 11 www.national.com LMH6714/6720/6722 Application Section (Continued) 20056517 20056522 FIGURE 11. Equalizer Frequency Response FIGURE 8. POWER DISSIPATION Follow these steps to determine the Maximum power dissipation for the LMH6714/6720/6722: 1. Calculate the quiescent (no load) power: PAMP = ICC (VCC -VEE) 2. Calculate the RMS power at the output stage: POUT (RMS) = ((VCC - VOUT (RMS)) * IOUT (RMS)), where VOUT and IOUT are the voltage and current across the external load. 3. Calculate the total RMS power: PT = PAMP + POUT The maximum power that the LMH6714/6720/6722, package can dissipate at a given temperature can be derived with the following equation: PMAX = (150˚ - TA)/ θJA, where TA = Ambient temperature (˚C) and θJA = Thermal resistance, from junction to ambient, for a given package (˚C/W). For the SOIC package θJA is 148˚C/W, for the SOT it is 250˚C/W. 20056529 FIGURE 9. Digital Signal without and with Equalization 20056530 FIGURE 10. Design Equations www.national.com 12 LMH6714/6720/6722 Physical Dimensions inches (millimeters) unless otherwise noted 5-Pin SOT23 NS Product Number MF05A 6-Pin SOT23 NS Product Number MF06A 13 www.national.com LMH6714/6720/6722 Physical Dimensions inches (millimeters) unless otherwise noted (Continued) 8-Pin SOIC NS Product Number M08A 14-Pin SOIC NS Product Number M14A www.national.com 14 LIFE SUPPORT POLICY NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein: 1. Life support devices or systems are devices or systems which, (a) are intended for surgical implant into the body, or (b) support or sustain life, and whose failure to perform when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in a significant injury to the user. National Semiconductor Americas Customer Support Center Email: [email protected] Tel: 1-800-272-9959 www.national.com National Semiconductor Europe Customer Support Center Fax: +49 (0) 180-530 85 86 Email: [email protected] Deutsch Tel: +49 (0) 69 9508 6208 English Tel: +44 (0) 870 24 0 2171 Français Tel: +33 (0) 1 41 91 8790 2. A critical component is any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness. National Semiconductor Asia Pacific Customer Support Center Fax: +65-6250 4466 Email: [email protected] Tel: +65-6254 4466 National Semiconductor Japan Customer Support Center Fax: 81-3-5639-7507 Email: [email protected] Tel: 81-3-5639-7560 National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications. LMH6714/6720/6722 Wideband Video Op Amp; Single, Single with Shutdown and Quad Notes