October 15, 2010 LMH6628EP Enhanced Plastic Dual Wideband, Low Noise, Voltage Feedback Op Amp General Description The National LMH6628EP is a high speed dual op amp that offers a traditional voltage feedback topology featuring unity gain stability and slew enhanced circuitry. The LMH6628EP's low noise and very low harmonic distortion combine to form a wide dynamic range op amp that operates from a single (5V to 12V) or dual (±5V) power supply. Each of the LMH6628EP's closely matched channels provides a 300MHz unity gain bandwidth and low input voltage ). Low 2nd/3rd harmonic distortion noise density (2nV/ (−65/−74dBc at 10MHz) make the LMH6628EP a perfect wide dynamic range amplifier for matched I/Q channels. With its fast and accurate settling (12ns to 0.1%), the LMH6628EP is also an excellent choice for wide dynamic range, anti-aliasing filters to buffer the inputs of hi resolution analog-to-digital converters. Combining the LMH6628EP's two tightly matched amplifiers in a single 8-pin SOIC package reduces cost and board space for many composite amplifier applications such as active filters, differential line drivers/receivers, fast peak detectors and instrumentation amplifiers. The LMH6628EP is fabricated using National’s VIP10™ complimentary bipolar process. To reduce design times and assist in board layout, the LMH6628EP is supported by an evaluation board (CLC730036). ENHANCED PLASTIC • • • • • • Extended Temperature Performance of −40°C to +85°C Baseline Control - Single Fab & Assembly Site Process Change Notification (PCN) Qualification & Reliability Data Solder (PbSn) Lead Finish is standard Enhanced Diminishing Manufacturing Sources (DMS) Support Features ■ ■ ■ ■ ■ ■ ■ Wide unity gain bandwidth: 300MHz Low noise: 2nV/ Low Distortion: −65/−74dBc (10MHz) Settling time: 12ns to 0.1% Wide supply voltage range: ±2.5V to ±6V High output current: ±85mA Improved replacement for CLC428 Applications ■ ■ ■ ■ High speed dual op amp Low noise integrators Selected Military Applications Selected Avionics Applications Ordering Information Part Number VID Part Number NS Package Number (Note 3) LMH6628MAEP V62/04624-01 M08A (Note 1, Note 2) TBD TBD Note 1: For the following (Enhanced Plastic) version, check for availability: LMH6628MAXEP. Parts listed with an "X" are provided in Tape & Reel and parts without an "X" are in Rails. Note 2: FOR ADDITIONAL ORDERING AND PRODUCT INFORMATION, PLEASE VISIT THE ENHANCED PLASTIC WEB SITE AT: www.national.com/ mil Note 3: Refer to package details under Physical Dimensions VIP10™ is a trademark of National Semiconductor Corporation. © 2010 National Semiconductor Corporation 200886 200886 Version 4 Revision 2 www.national.com Print Date/Time: 2010/10/15 15:22:20 LMH6628EP Enhanced Plastic Dual Wideband, Low Noise, Voltage Feedback Op Amp OBSOLETE LMH6628EP Enhanced Plastic Connection Diagram 8-Pin SOIC 20088635 Top View www.national.com 2 200886 Version 4 Revision 2 Print Date/Time: 2010/10/15 15:22:20 If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. ESD Tolerance (Note 7) Human Body Model Machine Model Supply Voltage Short Circuit Current Common-Mode Input Voltage Differential Input Voltage Operating Ratings Electrical Characteristics (Note 4) Thermal Resistance (Note 8) Package (θJC) 2kV 200V 13.5 (Note 6) V+ - V− V+ - V− +150°C −65°C to +150°C +300°C SOIC 65°C/W Temperature Range Nominal Supply Voltage (θJA) 145°C/W −40°C to +85°C ±2.5V to ±6V (Note 5) VCC = ±5V, AV = +2V/V, RF = 100Ω, RG = 100Ω, RL = 100Ω; unless otherwise specified. Boldface limits apply at the temperature extremes. Symbol Parameter Conditions Min Typ Max Units Frequency Domain Response GB Gain Bandwidth Product VO < 0.5VPP SSBW -3dB Bandwidth, AV = +1 VO < 0.5VPP SSBW -3dB Bandwidth, AV = +2 VO < 0.5VPP GFL Gain Flatness VO< 0.5VPP GFP Peaking GFR Rolloff LPD Linear Phase Deviation 200 MHz 300 MHz 100 MHz DC to 200MHz 0.0 dB DC to 20MHz .1 dB DC to 20MHz .1 deg 180 Time Domain Response TR Rise and Fall Time 1V Step 4 ns TS Settling Time 2V Step to 0.1% 12 ns OS Overshoot 1V Step 1 % SR Slew Rate 4V Step 550 V/µs 300 Distortion And Noise Response HD2 2nd Harmonic Distortion 1VPP, 10MHz −65 dBc HD3 3rd Harmonic Distortion 1VPP, 10MHz −74 dBc Equivalent Input Noise VN Voltage 1MHz to 100MHz 2 nV/ IN Current 1MHz to 100MHz 2 pA/ XTLKA Crosstalk Input Referred, 10MHz −62 dB 63 dB Static, DC Performance GOL Open-Loop Gain VIO Input Offset Voltage DVIO IBN DIBN IOS IOSD 56 53 ±.5 Average Drift 5 Input Bias Current ±.7 Average Drift 150 Input Offset Current 0.3 Average Drift ±2 ±2.6 mV µV/°C ±20 ±30 µA nA/°C ±6 µA 5 nA/°C PSRR Power Supply Rejection Ratio 60 46 70 dB CMRR Common-Mode Rejection Ratio 57 54 62 dB 3 200886 Version 4 Revision 2 Print Date/Time: 2010/10/15 15:22:20 www.national.com LMH6628EP Enhanced Plastic Maximum Junction Temperature Storage Temperature Range Lead Temperature (soldering 10 sec) Absolute Maximum Ratings (Note 4) LMH6628EP Enhanced Plastic Symbol ICC Parameter Supply Current Conditions Min Typ Max Units Per Channel, RL = ∞ 7.5 7.0 9 12 12.5 mA Miscellaneous Performance RIN Input Resistance Common-Mode 500 kΩ CIN Input Capacitance Differential-Mode 200 kΩ Common-Mode 1.5 pF ROUT Output Resistance Differential-Mode 1.5 pF Closed-Loop .1 VO Output Voltage Range Ω ±3.8 RL = ∞ V ±3.5 V ±3.7 V ±85 mA RL = 100Ω VOL CMIR Input Voltage Range IO Output Current ±3.2 ±3.1 Common- Mode ±50 Note 4: 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 5: 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 Note 6 for information on temperature de-rating of this device." Min/Max ratings are based on product characterization and simulation. Individual parameters are tested as noted. Note 6: Output is short circuit protected to ground, however maximum reliability is obtained if output current does not exceed 160mA. Note 7: Human body model, 1.5kΩ in series with 100pF. Machine model, 0Ω In series with 200pF. Note 8: The maximum power dissipation is a function of TJ(MAX), θJA and TA. The maximum allowable power dissipation at any ambient temperature is PD = (TJ(MAX)-TA)/ θJA. All numbers apply for packages soldered directly onto a PC board. Typical Performance Characteristics (TA = +25°, AV = +2, VCC = ±5V, Rf =100Ω, RL = 100Ω, unless specified) Non-Inverting Frequency Response Inverting Frequency Response 20088615 20088613 www.national.com 4 200886 Version 4 Revision 2 Print Date/Time: 2010/10/15 15:22:20 LMH6628EP Enhanced Plastic Frequency Response vs. Load Resistance Frequency Response vs. Output Amplitude 20088610 20088625 Frequency Response vs. Capacitive Load Gain Flatness & Linear Phase 20088616 20088624 5 200886 Version 4 Revision 2 Print Date/Time: 2010/10/15 15:22:20 www.national.com LMH6628EP Enhanced Plastic Channel Matching Channel to Channel Crosstalk 20088614 Pulse Response (VO = 2V) 20088609 Pulse Response (VO = 100mV) 20088611 www.national.com 20088612 6 200886 Version 4 Revision 2 Print Date/Time: 2010/10/15 15:22:20 LMH6628EP Enhanced Plastic 2nd Harmonic Distortion vs. Output Voltage 3rd Harmonic Distortion vs. Output Voltage 20088607 20088608 2nd & 3rd Harmonic Distortion vs. Frequency PSRR and CMRR (±5V) 20088622 20088617 7 200886 Version 4 Revision 2 Print Date/Time: 2010/10/15 15:22:20 www.national.com LMH6628EP Enhanced Plastic PSRR and CMRR (±2.5V) Closed Loop Output Resistance (±2.5V) 20088623 20088618 Closed Loop Output Resistance (±5V) Open Loop Gain & Phase (±2.5V) 20088619 www.national.com 20088621 8 200886 Version 4 Revision 2 Print Date/Time: 2010/10/15 15:22:20 LMH6628EP Enhanced Plastic Open Loop Gain & Phase (±5V) Recommended RS vs. CL 20088620 20088626 DC Errors vs. Temperature Maximum VO vs. RL 20088646 9 200886 Version 4 Revision 2 Print Date/Time: 2010/10/15 15:22:20 20088645 www.national.com LMH6628EP Enhanced Plastic 2-Tone, 3rd Order Intermodulation Intercept Voltage & Current Noise vs. Frequency 20088644 20088647 Settling Time vs. Accuracy 20088648 OUTPUT AND SUPPLY CONSIDERATIONS With ±5V supplies, the LMH6628EP is capable of a typical output swing of ±3.8V under a no-load condition. Additional output swing is possible with slightly higher supply voltages. For loads of less than 50Ω, the output swing will be limited by the LMH6628EP's output current capability, typically 85mA. Output settling time when driving capacitive loads can be improved by the use of a series output resistor. See the plot labeled "RS vs. CL" in the Typical Performance section. Application Section LOW NOISE DESIGN Ultimate low noise performance from circuit designs using the LMH6628EP requires the proper selection of external resistors. By selecting appropriate low valued resistors for RF and RG, amplifier circuits using the LMH6628EP can achieve output noise that is approximately the equivalent voltage input multiplied by the desired gain (AV). noise of 2nV/ LAYOUT Proper power supply bypassing is critical to insure good high frequency performance and low noise. De-coupling capacitors of 0.1μF should be placed as close as possible to the power supply pins. The use of surface mounted capacitors is recommended due to their low series inductance. A good high frequency layout will keep power supply and ground traces away from the inverting input and output pins. Parasitic capacitance from these nodes to ground causes frequency response peaking and possible circuit oscillation. See OA-15 for more information. National suggests the 730036 DC BIAS CURRENTS AND OFFSET VOLTAGES Cancellation of the output offset voltage due to input bias currents is possible with the LMH6628EP. This is done by making the resistance seen from the inverting and non-inverting inputs equal. Once done, the residual output offset voltage will be the input offset voltage (VOS) multiplied by the desired gain (AV). National Application Note OA-7 offers several solutions to further reduce the output offset. www.national.com 10 200886 Version 4 Revision 2 Print Date/Time: 2010/10/15 15:22:20 the circuit and provides a high input impedance for the source. As shown in Figure 2, the circuit provides a 13.1ns delay (with R = 40.2Ω, C = 47pF). RF and RG should be of equal and low value for parasitic insensitive operation. ANALOG DELAY CIRCUIT (ALL-PASS NETWORK) The circuit in Figure 1 implements an all-pass network using the LMH6628EP. A wide bandwidth buffer (LM7121) drives 20088601 FIGURE 1. In the circuit shown in Figure 3, one of the LMH6628EP's amps is used as a "driver" and the other as a difference "receiver" amplifier. The output impedance of the "driver" is essentially zero. The two R's are chosen to match the characteristic impedance of the transmission line. The "driver" op amp gain can be selected for unity or greater. Receiver amplifier A2 (B2) is connected across R and forms differential amplifier for the signals transmitted by driver A2 (B2). If RF equals RG, receiver A2 (B1) will then reject the signals from driver A1 (B1) and pass the signals from driver B1 (A1). 20088602 FIGURE 2. Delay Circuit Response to 0.5V Pulse The circuit gain is +1 and the delay is determined by the following equations. 20088603 (1) FIGURE 3. The output of the receiver amplifier will be: (2) where Td is the delay of the op amp at AV = +1. The LMH6628EP provides a typical delay of 2.8ns at its −3dB point. (3) Care must be given to layout and component placement to maintain a high frequency common-mode rejection. The plot of Figure 4 shows the simultaneous reception of signals transmitted at 1MHz and 10MHz. FULL DUPLEX DIGITAL OR ANALOG TRANSMISSION Simultaneous transmission and reception of analog or digital signals over a single coaxial cable or twisted-pair line can reduce cabling requirements. The LMH6628EP's wide bandwidth and high common-mode rejection in a differential amplifier configuration allows full duplex transmission of video, telephone, control and audio signals. 11 200886 Version 4 Revision 2 Print Date/Time: 2010/10/15 15:22:20 www.national.com LMH6628EP Enhanced Plastic (SOIC) dual op amp evaluation board as a guide for high frequency layout and as an aid in device evaluation. LMH6628EP Enhanced Plastic 20088631 20088637 FIGURE 4. FIGURE 6. POSITIVE PEAK DETECTOR The LMH6628EP's dual amplifiers can be used to implement a unity-gain peak detector circuit as shown in Figure 5. A current source, built around Q1, provides the necessary bias current for the second amplifier and prevents saturation when power is applied. The resistor, R, closes the loop while diode D2 prevents negative saturation when VIN is less than VC. A MOS-type switch (not shown) can be used to reset the capacitor's voltage. The maximum speed of detection is limited by the delay of the op amps and the diodes. The use of Schottky diodes will provide faster response. ADJUSTABLE OR BANDPASS EQUALIZER A "boost" equalizer can be made with the LMH6628EP by summing a bandpass response with the input signal, as shown in Figure 7. 20088605 FIGURE 5. The acquisition speed of this circuit is limited by the dynamic resistance of the diode when charging Chold. A plot of the circuit's performance is shown in Figure 6 with a 1MHz sinusoidal input. 20088606 FIGURE 7. The overall transfer function is shown in Eq. 5. (4) To build a boost circuit, use the design equations Eq. 6 and Eq. 7. (5) www.national.com 12 200886 Version 4 Revision 2 Print Date/Time: 2010/10/15 15:22:20 LMH6628EP Enhanced Plastic (6) Select R2 and C using Eq. 6. Use reasonable values for high frequency circuits - R2 between 10Ω and 5kΩ, C between 10pF and 2000pF. Use Eq. 7 to determine the parallel combination of Ra and Rb. Select Ra and Rb by either the 10Ω to 5kΩ criteria or by other requirements based on the impedance Vin is capable of driving. Finish the design by determining the value of K from Eq. 8. (7) Figure 8 shows an example of the response of the circuit of Figure 9, where fo is 2.3MHz. The component values are as follows: Ra=2.1kΩ, Rb = 68.5Ω, R2 = 4.22kΩ, R = 500Ω, KR = 50Ω, C = 120pF. 20088643 FIGURE 8. 13 200886 Version 4 Revision 2 Print Date/Time: 2010/10/15 15:22:20 www.national.com LMH6628EP Enhanced Plastic Physical Dimensions inches (millimeters) unless otherwise noted 8-Pin SOIC NS Package Number M08A www.national.com 14 200886 Version 4 Revision 2 Print Date/Time: 2010/10/15 15:22:20 LMH6628EP Enhanced Plastic Notes 15 200886 Version 4 Revision 2 Print Date/Time: 2010/10/15 15:22:20 www.national.com LMH6628EP Enhanced Plastic Dual Wideband, Low Noise, Voltage Feedback Op Amp Notes For more National Semiconductor product information and proven design tools, visit the following Web sites at: www.national.com Products Design Support Amplifiers www.national.com/amplifiers WEBENCH® Tools www.national.com/webench Audio www.national.com/audio App Notes www.national.com/appnotes Clock and Timing www.national.com/timing Reference Designs www.national.com/refdesigns Data Converters www.national.com/adc Samples www.national.com/samples Interface www.national.com/interface Eval Boards www.national.com/evalboards LVDS www.national.com/lvds Packaging www.national.com/packaging Power Management www.national.com/power Green Compliance www.national.com/quality/green Switching Regulators www.national.com/switchers Distributors www.national.com/contacts LDOs www.national.com/ldo Quality and Reliability www.national.com/quality LED Lighting www.national.com/led Feedback/Support www.national.com/feedback Voltage References www.national.com/vref Design Made Easy www.national.com/easy www.national.com/powerwise Applications & Markets www.national.com/solutions Mil/Aero www.national.com/milaero PowerWise® Solutions Serial Digital Interface (SDI) www.national.com/sdi Temperature Sensors www.national.com/tempsensors SolarMagic™ www.national.com/solarmagic PLL/VCO www.national.com/wireless www.national.com/training PowerWise® Design University THE CONTENTS OF THIS DOCUMENT ARE PROVIDED IN CONNECTION WITH NATIONAL SEMICONDUCTOR CORPORATION (“NATIONAL”) PRODUCTS. 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