LMH6609 900MHz Voltage Feedback Op Amp General Description Features The LMH6609 is an ultra wideband, unity gain stable, low power, voltage feedback op amp that offers 900MHz bandwidth at a gain of 1, 1400V/µs slew rate and 90mA of linear output current. The LMH6609 is designed with voltage feedback architecture for maximum flexibility especially for active filters and integrators. The LMH6609 has balanced, symmetrical inputs with well-matched bias currents and minimal offset voltage. With Differential Gain of .01 and Differential Phase of .026 the LMH6609 is suited for video applications. The 90mA of linear output current makes the LMH6609 suitable for multiple video loads and cable driving applications as well. n n n n n n n n n n n n The recommended supply voltage range of 6V to 12V and is specified at 6.6 and 10V. A low supply current of 7mA (at 10V supply) makes the LMH6609 useful in a wide variety of platforms, including portable or remote equipment that must run from battery power. The LMH6609 is available in the industry standard 8-pin SOIC package and in the space-saving 5-pin SOT package. The LMH6609 is specified for operation over the -40˚C to +85˚C temperature range. The LMH6609 is manufactured in National Semiconductor’s state-of-the-art VIP10™ technology for high performance. 900MHz −3dB bandwidth (AV = 1) Large signal bandwidth and slew rate 100% tested 280MHz −3dB bandwidth (AV = +2, VOUT = 2VPP) 90mA linear output current 1400V/µs slew rate Unity gain stable < 1mV input Offset voltage 7mA Supply current (no load) 6V to 12V supply voltage range .01/ .026 differential gain/phase PAL 3.1nV/ voltage noise Improved replacement for CLC440, 420, 426 Applications n n n n n n n Test equipment IF/RF amplifier A/D Input driver Active filter Integrator DAC output buffer Transimpedance amplifier Typical Application 20079037 20079038 Sallen Key Low Pass Filter © 2003 National Semiconductor Corporation DS200790 www.national.com LMH6609 900MHz Voltage Feedback Op Amp August 2003 LMH6609 Absolute Maximum Ratings Machine Model (Note 1) If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. VS (V+ - V−) Operating Ratings (Note 3) Thermal Resistance ± 6.6V IOUT Package (Note 3) Common Mode Input Voltage V+ to V− Maximum Junction Temperature Storage Temperature Range +150˚C −65˚C to +150˚C Lead Temperature Range +300˚C ESD Tolerance (Note 4) Human Body Model 200V (θJC) (θJA) 8-Pin SOIC 65˚C/W 145˚C/W 5-Pin SOT23 120˚C/W 187˚C/W Operating Temperature −40˚C +85˚C Nominal Supply Voltage (Note 6) ± 3.3V ± 6V 2000V ± 5V Electrical Characteristics Unless specified, AV = +2, RF = 250Ω: VS = ± 5V, RL = 100Ω; unless otherwise specified. Boldface limits apply over temperature Range. (Note 2) Symbol Parameter Conditions Min Typ Max Units Frequency Domain Response SSBW −3dB Bandwidth VOUT = 0.5VPP LSBW −3dB Bandwidth VOUT = 4.0VPP 150 260 MHz 170 MHz SSBWG1 −3dB Bandwidth AV = 1 VOUT = 0.25VPP 900 MHz GFP .1dB Bandwidth Gain is Flat to .1dB 130 MHz DG Differential Gain RL = 150Ω, 4.43MHz 0.01 % DP Differential Phase RL = 150Ω, 4.43MHz 0.026 deg 1V Step 1.6 ns 4V Step 2.6 ns Time Domain Response TRS Rise and Fall Time TRL ts Settling Time to 0.05% 2V Step SR Slew Rate 4V Step (Note 5) 1200 15 ns 1400 V/µs Distortion and Noise Response HD2 2nd Harmonic Distortion 2VPP, 20MHz −63 dBc HD3 3rd Harmonic Distortion 2VPP, 20MHz −57 dBc > 1MHz > 1MHz 3.1 nV/ 1.6 pA/ Equivalent Input Noise VN Voltage Noise CN Current Noise Static, DC Performance ± 0.8 ± 2.5 ± 3.5 ±5 ±8 ± 1.5 ±3 mV VIO Input Offset Voltage IBN Input Bias Current −2 IBI Input Offset Current .1 PSRR Power Supply Rejection Ratio DC, 1V Step 67 65 73 dB CMRR Common Mode Rejection Ratio DC, 2V Step 67 65 73 dB ICC Supply Current RL = ∞ 7.0 7.8 8.5 µA µA mA Miscellaneous Performance RIN Input Resistance CIN Input Capacitance ROUT Output Resistance www.national.com Closed Loop 2 1 MΩ 1.2 pF 0.3 Ω (Continued) Unless specified, AV = +2, RF = 250Ω: VS = ± 5V, RL = 100Ω; unless otherwise specified. Boldface limits apply over temperature Range. (Note 2) Symbol VO Parameter Output Voltage Range Conditions RL = ∞ RL = 100Ω VOL CMIR Input Voltage Range Common Mode, CMRR > 60dB IO Linear Output Current VOUT Min Typ Max Units ± 3.6 ± 3.3 ± 3.2 ± 3.0 ± 2.8 ± 2.5 ± 60 ± 50 ± 3.9 V ± 3.5 V ± 3.0 V ± 90 mA ± 3.3V Electrical Characteristics Unless specified, AV = +2, RF = 250Ω: VS = ± 3.3V, RL = 100Ω; unless otherwise specified. Boldface limits apply over temperature Range. (Note 2) Symbol Parameter Conditions Min Typ Max Units Frequency Domain Response SSBW −3dB Bandwidth VOUT = 0.5VPP 180 MHz LSBW −3dB Bandwidth VOUT = 3.0VPP 110 MHz SSBWG1 −3dB Bandwidth AV = 1 VOUT = 0.25VPP 450 MHz GFP .1dB Bandwidth VOUT = 1VPP 40 MHz DG Differential Gain RL = 150Ω, 4.43MHz .01 % DP Differential Phase RL = 150Ω, 4.43MHz .06 deg Time Domain Response TRL SR Slew Rate 1V Step 2.2 ns 2V Step (Note 5) 800 V/µs Distortion and Noise Response HD2 2nd Harmonic Distortion 2VPP, 20MHz −63 dBc HD3 3rd Harmonic Distortion 2VPP, 20MHz −43 dBc > 1MHz > 1MHz 3.7 nV/ 1.1 pA/ Equivalent Input Noise VN Voltage Noise CN Current Noise Static, DC Performance VIO Input Offset Voltage 0.8 IBN Input Bias Current −1 IBI Input Offset Current 0 PSRR Power Supply Rejection Ratio DC, .5V Step 67 CMRR Common Mode Rejection Ratio DC, 1V Step 67 ICC Supply Current RL = ∞ ± 2.5 ± 3.5 ±3 ±6 ± 1.5 ±3 73 µA µA dB 75 3.6 mV dB 5 6 mA Miscellaneous Performance ROUT Input Resistance VO Output Voltage Range VOL Close Loop RL = ∞ ± 2.1 ± 1.9 RL = 100Ω CMIR Input Voltage Range Common Mode IO Linear Output Current VOUT ± 30 3 .05 Ω ± 2.3 ± 2.0 ± 1.3 ± 45 V V V mA www.national.com LMH6609 ± 5V Electrical Characteristics LMH6609 ± 3.3V Electrical Characteristics (Continued) 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 Section for more details. Note 4: Human body model, 1.5kΩ in series with 100pF. Machine model, 0Ω In series with 200pF. Note 5: rate is Average of Rising and Falling 40-60% slew rates. Note 6: Nominal Supply voltage range is for supplies with regulation of 10% or better. Connection Diagrams 5-Pin SOT23 8-Pin SOIC 20079039 20079040 Top View Top View Ordering Information Package 8-Pin SOIC 5-SOT23 www.national.com Part Number LMH6609MA LMH6609MAX LMH6609MF LMH6609MFX Package Marking Transport Media 95 Units/Rails LMH6609MA 2.5k Units Tape and Reel 1k Units Tape and Reel A89A 2.5k Units Tape and Reel 4 NSC Drawing M08A MF05A Small Signal Non-Inverting Frequency Response Large Signal Non-Inverting Frequency Response 20079004 20079003 Small Signal Inverting Frequency Response Large Signal Inverting Frequency Response 20079002 20079010 Frequency Response vs. VOUT AV = 2 Frequency Response vs. VOUT AV = 2 20079009 20079001 5 www.national.com LMH6609 Typical Performance Characteristics LMH6609 Typical Performance Characteristics (Continued) Frequency Response vs. VOUT AV = 1 Frequency Response vs. VOUT AV = −1 20079007 20079008 Frequency Response vs. VOUT AV = −1 Frequency Response vs. Cap Load 20079042 20079006 Frequency Response vs. Cap Load Suggested ROUT vs. Cap Load 20079041 20079043 www.national.com 6 LMH6609 Typical Performance Characteristics (Continued) CMRR vs. Frequency PSRR vs. Frequency 20079011 20079012 PSRR vs. Frequency Pulse Response 20079013 20079016 Pulse Response Large Signal Pulse Response 20079014 20079015 7 www.national.com LMH6609 Typical Performance Characteristics (Continued) Noise vs. Frequency HD2 vs. VOUT 20079025 20079018 HD3 vs. VOUT HD2 vs. VOUT 20079020 20079017 HD3 vs. VOUT HD2 & HD3 vs. Frequency 20079021 20079019 www.national.com 8 LMH6609 Typical Performance Characteristics (Continued) HD2 & HD3 vs. Frequency Differential Gain & Phase 20079022 20079046 Differential Gain & Phase Open Loop Gain & Phase 20079044 20079047 Open Loop Gain & Phase Closed Loop Output Resistance 20079045 20079023 9 www.national.com LMH6609 Application Section GENERAL DESIGN EQUATION The LMH6609 is a unity gain stable voltage feedback amplifier. The matched input bias currents track well over temperature. This allows the DC offset to be minimized by matching the impedance seen by both inputs. GAIN The non-inverting and inverting gain equations for the LMH6609 are as follows: 20079028 FIGURE 2. Typical Inverting Application 20079027 FIGURE 1. Typical Non-Inverting Application 20079029 FIGURE 3. Single Supply Inverting www.national.com 10 time. Refer to the Driving Capacitive Loads section for guidance on selecting an output resistor for driving capacitive loads. (Continued) EVALUATION BOARDS National Semiconductor provides the following evaluation boards as a guide for high frequency layout and as an aid in device testing and characterization. Many of the datasheet plots were measured with these boards. Device Package Board Part # LMH6609MA SOIC CLC730227 LMH6609MF SOT-23 CLC730216 A free evaluation board is automatically shipped when a sample request is placed with National Semiconductor. CIRCUIT LAYOUT CONSIDERATION A proper printed circuit layout is essential for achieving high frequency performance. National provides evaluation boards for the LMH6609 as shown above. These boards were laid out for optimum, high-speed performance. The ground plane was removed near the input and output pins to reduce parasitic capacitance. Also, all trace lengths were minimized to reduce series inductances. Supply bypassing is required for the amplifiers performance. The bypass capacitors provide a low impedance return current path at the supply pins. They also provide high frequency filtering on the power supply traces. 10µF tantalum and .01µF capacitors are recommended on both supplies (from supply to ground). In addition a .1µF ceramic capacitor can be added from V+ to V− to aid in second harmonic suppression. 20079030 FIGURE 4. AC Coupled Non-Inverting GAIN BANDWIDTH PRODUCT The LMH6609 is a voltage feedback amplifier, whose closed-loop bandwidth is approximately equal to the gainbandwidth product (GBP) divided by the gain (AV). For gains greater than 5, AV sets the closed-loop bandwidth of the LMH6609. 20079033 20079031 FIGURE 5. Driving Capacitive Loads with ROUT for Improved Stability For Gains less than 5, refer to the frequency response plots to determine maximum bandwidth. For large signal bandwidth the slew rate is a more accurate predictor of bandwidth. DRIVING CAPACITIVE LOADS Capacitive output loading applications will benefit from the use of a series output resistor ROUT. Figure 5 shows the use of a series output resistor, ROUT as it might be applied when driving an analog to digital converter. The charts "Suggested RO vs. Cap Load" in the Typical Performance Section give a recommended value for mitigating capacitive loads. The values suggested in the charts are selected for .5dB or less of peaking in the frequency response. This gives a good compromise between settling time and bandwidth. For applications where maximum frequency response is needed and some peaking is tolerable, the value of RO can be reduced slightly from the recommended values. There will be amplitude lost in the series resistor unless the gain is adjusted to compensate; this effect is most noticeable with heavy resistive loads. 20079032 Where fMAX = bandwidth, SR = Slew rate and VP = peak amplitude. OUTPUT DRIVE AND SETTLING TIME PERFORMANCE The LMH6609 has large output current capability. The 100mA of output current makes the LMH6609 an excellent choice for applications such as: • Video Line Drivers • Distribution Amplifiers When driving a capacitive load or coaxial cable, include a series resistance ROUT to back match or improve settling 11 www.national.com LMH6609 Application Section LMH6609 Application Section quency content of the signal. 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 transmission line and other parasitic capacitances from the amplifier output stage. This means that the device should be configured for a gain of 2 in order to have a net gain of 1 after the terminating resistor. (See Figure 6) (Continued) COMPONENT SELECTION AND FEEDBACK RESISTOR Surface mount components are highly recommended for the LMH6609. Leaded components will introduce unpredictable parasitic loading that will interfere with proper device operation. Do not use wire wound resistors. The LMH6609 operates best with a feedback resistor of approximately 250Ω for all gains of +2 and greater and for −1 and less. With lower gains in particular, large value feedback resistors will exaggerate the effects of parasitic capacitances and may lead to ringing on the pulse response and frequency response peaking. Large value resistors also add undesirable thermal noise. Feedback resistors that are much below 100Ω will load the output stage, which will reduce voltage output swing, increase device power dissipation, increase distortion and reduce current available for driving the load. In the buffer configuration the output should be shorted directly to the inverting input. This feedback does not load the output stage because the inverting input is a high impedance point and there is no gain set resistor to ground. OPTIMIZING DC ACCURACY The LMH6609 offers excellent DC accuracy. The wellmatched inputs of this amplifier allows even better performance if care is taken to balance the impedances seen by the two inputs. The parallel combination of the gain setting RG and feedback RF resistors should be equal to RSEQ, the resistance of the source driving the op amp in parallel with any terminating Resistor (See Figure 1). Combining this with the non inverting gain equation gives the following parameters: RF = AVRSEQ 20079034 FIGURE 6. Typical Video Application ESD PROTECTION The LMH6609 is protected against electrostatic discharge (ESD) on all pins. The LMH6609 will survive 2000V Human Body model or 200V Machine model events. Under closed loop operation the ESD diodes have no effect on circuit performance. There are occasions, however, when the ESD diodes may be evident. For instance, if the amplifier is powered down and a large input signal is applied the ESD diodes will conduct. RG = RF/(AV−1) For Inverting gains the bias current cancellation is accomplished by placing a resistor RB on the non-inverting input equal in value to the resistance seen by the inverting input (See Figure 2). RB = RF || (RG + RS) The additional noise contribution of RB can be minimized by the use of a shunt capacitor (not shown). POWER DISSIPATION The LMH6609 has the ability to drive large currents into low impedance loads. Some combinations of ambient temperature and device loading could result in device overheating. For most conditions peak power values are not as important as RMS powers. To determine the maximum allowable power dissipation for the LMH6609 use the following formula: PMAX = (150o - TAMB)/θJA Where TAMB = 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. 150oC is the absolute maximum limit for the internal temperature of the device. Either forced air cooling or a heat sink can greatly increase the power handling capability for the LMH6609. TRANSIMPEDANCE AMPLIFIER The low input current noise and unity gain stability of the LMH6609 make it an excellent choice for transimpedance applications. Figure 7 illustrates a low noise transimpedance amplifier that is commonly implemented with photo diodes. RF sets the transimpedance gain. The photo diode current multiplied by RF determines the output voltage. VIDEO PERFORMANCE The LMH6609 has been designed to provide good performance with both PAL and NTSC composite video signals. The LMH6609 is specified for PAL signals. NTSC performance is typically marginally better due to the lower frewww.national.com 12 Rectifier (Continued) The large bandwidth of the LMH6609 allows for high-speed rectification. A common rectifier topology is shown in Figure 8. R1 and R2 set the gain of the rectifier. 20079035 FIGURE 7. Transimpedance Amplifier 20079036 The capacitances are defined as: • CD = Equivalent Diode Capacitance • CF = Feedback Capacitance The feedback capacitor is used to give optimum flatness and stability. As a starting point the feedback capacitance should be chosen as 1⁄2 of the Diode capacitance. Lower feedback capacitors will peak frequency response. FIGURE 8. Rectifier Topology 13 www.national.com LMH6609 Application Section LMH6609 Physical Dimensions inches (millimeters) unless otherwise noted 8-Pin SOIC NS Product Number M08A 5-Pin SOT23 NS Product Number MF05A www.national.com 14 LMH6609 900MHz Voltage Feedback Op Amp Notes 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 Email: [email protected] 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.