250 MHz, General Purpose Voltage Feedback Op Amps AD8047/AD8048 FEATURES Wide Bandwidth AD8047, G = +1 Small Signal 250 MHz Large Signal (2 V p-p) 130 MHz AD8048, G = +2 260 MHz 160 MHz 5.8 mA Typical Supply Current Low Distortion, (SFDR) Low Noise –66 dBc Typ @ 5 MHz –54 dBc Typ @ 20 MHz 5.2 nV/√Hz (AD8047), 3.8 nV/√Hz (AD8048) Noise Drives 50 pF Capacitive Load High Speed Slew Rate 750 V/s (AD8047), 1000 V/s (AD8048) Settling 30 ns to 0.01%, 2 V Step 3 V to 6 V Supply Operation APPLICATIONS Low Power ADC Input Driver Differential Amplifiers IF/RF Amplifiers Pulse Amplifiers Professional Video DAC Current to Voltage Conversion Baseband and Video Communications Pin Diode Receivers Active Filters/Integrators FUNCTIONAL BLOCK DIAGRAM 8-Pin Plastic PDIP (N) and SOIC (R) Packages AD8047/ AD8048 8 NC 2 7 +VS +INPUT 3 6 OUTPUT –V S 4 5 NC NC 1 –INPUT (TOP VIEW) NC = NO CONNECT The AD8047 and AD8048’s low distortion and cap load drive make the AD8047/AD8048 ideal for buffering high speed ADCs. They are suitable for 12-bit/10 MSPS or 8-bit/60 MSPS ADCs. Additionally, the balanced high impedance inputs of the voltage feedback architecture allow maximum flexibility when designing active filters. The AD8047 and AD8048 are offered in industrial (–40°C to +85°C) temperature ranges and are available in 8-lead PDIP and SOIC packages. PRODUCT DESCRIPTION The AD8047 and AD8048 are very high speed and wide bandwidth amplifiers. The AD8047 is unity gain stable. The AD8048 is stable at gains of two or greater. The AD8047 and AD8048, which utilize a voltage feedback architecture, meet the requirements of many applications that previously depended on current feedback amplifiers. A proprietary circuit has produced an amplifier that combines many of the best characteristics of both current feedback and voltage feedback amplifiers. For the power (6.6 mA max), the AD8047 and AD8048 exhibit fast and accurate pulse response (30 ns to 0.01%) as well as extremely wide small signal and large signal bandwidth and low distortion. The AD8047 achieves –54 dBc distortion at 20 MHz, 250 MHz small signal, and 130 MHz large signal bandwidths. 1V 5ns Figure 1. AD8047 Large Signal Transient Response, VO = 4 V p-p, G = +1 REV. A Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Trademarks and registered trademarks are the property of their respective companies. One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. Tel: 781/329-4700 www.analog.com Fax: 781/326-8703 © 2003 Analog Devices, Inc. All rights reserved. Powered by TCPDF (www.tcpdf.org) IMPORTANT LINKS for the AD8047_8048* Last content update 08/19/2013 04:41 pm PARAMETRIC SELECTION TABLES DESIGN TOOLS, MODELS, DRIVERS & SOFTWARE Find Similar Products By Operating Parameters High Speed Amplifiers Selection Table dBm/dBu/dBv Calculator Analog Filter Wizard 2.0 Power Dissipation vs Die Temp ADIsimOpAmp™ OpAmp Stability AD8047 SPICE Macro-Model DOCUMENTATION AN-649: Using the Analog Devices Active Filter Design Tool AN-581: Biasing and Decoupling Op Amps in Single Supply Applications AN-402: Replacing Output Clamping Op Amps with Input Clamping Amps AN-417: Fast Rail-to-Rail Operational Amplifiers Ease Design Constraints in Low Voltage High Speed Systems MT-060: Choosing Between Voltage Feedback and Current Feedback Op Amps MT-059: Compensating for the Effects of Input Capacitance on VFB and CFB Op Amps Used in Current-to-Voltage Converters MT-058: Effects of Feedback Capacitance on VFB and CFB Op Amps MT-056: High Speed Voltage Feedback Op Amps MT-053: Op Amp Distortion: HD, THD, THD + N, IMD, SFDR, MTPR MT-052: Op Amp Noise Figure: Don’t Be Mislead MT-050: Op Amp Total Output Noise Calculations for Second-Order System MT-049: Op Amp Total Output Noise Calculations for Single-Pole System MT-048: Op Amp Noise Relationships: 1/f Noise, RMS Noise, and Equivalent Noise Bandwidth MT-047: Op Amp Noise MT-033: Voltage Feedback Op Amp Gain and Bandwidth MT-032: Ideal Voltage Feedback (VFB) Op Amp A Stress-Free Method for Choosing High-Speed Op Amps UG-101: Evaluation Board User Guide Choosing High-Speed Signal Processing Components for Ultrasound Systems FOR THE AD8047 AN-214: Ground Rules for High Speed Circuits EVALUATION KITS & SYMBOLS & FOOTPRINTS View the Evaluation Boards and Kits page for the AD8047 View the Evaluation Boards and Kits page for the AD8048 Symbols and Footprints for the AD8047 Symbols and Footprints for the AD8048 DESIGN COLLABORATION COMMUNITY Collaborate Online with the ADI support team and other designers about select ADI products. Follow us on Twitter: www.twitter.com/ADI_News Like us on Facebook: www.facebook.com/AnalogDevicesInc DESIGN SUPPORT Submit your support request here: Linear and Data Converters Embedded Processing and DSP Telephone our Customer Interaction Centers toll free: Americas: Europe: China: India: Russia: 1-800-262-5643 00800-266-822-82 4006-100-006 1800-419-0108 8-800-555-45-90 Quality and Reliability Lead(Pb)-Free Data SAMPLE & BUY AD8047 AD8048 View Price & Packaging Request Evaluation Board Request Samples Check Inventory & Purchase Find Local Distributors * This page was dynamically generated by Analog Devices, Inc. and inserted into this data sheet. Note: Dynamic changes to the content on this page (labeled 'Important Links') does not constitute a change to the revision number of the product data sheet. This content may be frequently modified. AD8047/AD8048–SPECIFICATIONS ELECTRICAL CHARACTERISTICS Parameter DYNAMIC PERFORMANCE Bandwidth (–3 dB) Small Signal Large Signal1 Bandwidth for 0.1 dB Flatness Slew Rate, Average +/– Rise/Fall Time Settling Time To 0.1% To 0.01% HARMONIC/NOISE PERFORMANCE Second Harmonic Distortion Third Harmonic Distortion Input Voltage Noise Input Current Noise Average Equivalent Integrated Input Noise Voltage Differential Gain Error (3.58 MHz) Differential Phase Error (3.58 MHz) (VS = 5 V, RLOAD = 100 , AV = 1 (AD8047), AV = 2 (AD8048), unless otherwise noted.) Conditions Min VOUT ≤ 0.4 V p-p VOUT = 2 V p-p VOUT = 300 mV p-p AD8047, RF = 0 Ω; AD8048, RF = 200 Ω VOUT = 4 V Step VOUT = 0.5 V Step VOUT = 4 V Step 170 100 AD8047A Typ Max 475 250 130 35 750 1.1 4.3 Unit 180 135 260 160 MHz MHz 50 1000 1.2 3.2 MHz V/µs ns ns 740 VOUT = 2 V Step VOUT = 2 V Step 13 30 13 30 ns ns 2 V p-p; 20 MHz RL = 1 kΩ 2 V p-p; 20 MHz RL = 1 kΩ f = 100 kHz f = 100 kHz –54 –64 –60 –61 5.2 1.0 –48 –60 –56 –65 3.8 1.0 dBc dBc dBc dBc nV/√Hz pA/√Hz 0.1 MHz to 10 MHz RL = 150 Ω, G = +2 RL = 150 Ω, G = +2 16 0.02 0.03 11 0.01 0.02 µV rms % Degree DC PERFORMANCE2, RL = 150 Ω Input Offset Voltage3 1 TMIN to TMAX ±5 1 Offset Voltage Drift Input Bias Current TMIN to TMAX Input Offset Current Common-Mode Rejection Ratio Open-Loop Gain AD8048A Min Typ Max 0.5 TMIN to TMAX VCM = ± 2.5 V VOUT = ± 2.5 V TMIN to TMAX 74 58 54 INPUT CHARACTERISTICS Input Resistance Input Capacitance Input Common-Mode Voltage Range OUTPUT CHARACTERISTICS Output Voltage Range, RL = 150 Ω Output Current Output Resistance Short-Circuit Current POWER SUPPLY Operating Range Quiescent Current 1 ±5 1 3.5 6.5 2 3 80 62 0.5 74 65 56 3 4 3.5 6.5 2 3 80 68 mV mV µV/°C µA µA µA µA dB dB dB 500 1.5 ± 3.4 500 1.5 ± 3.4 kΩ pF V ± 2.8 ± 3.0 50 0.2 130 ± 2.8 ± 3.0 50 0.2 130 V mA Ω mA ± 3.0 ± 5.0 ± 6.0 5.8 6.6 7.5 78 ± 3.0 ± 5.0 ± 6.0 5.9 6.6 7.5 72 78 V mA mA dB TMIN to TMAX Power Supply Rejection Ratio 3 4 72 NOTES 1 See Absolute Maximum Ratings and Theory of Operation sections. 2 Measured at AV = 50. 3 Measured with respect to the inverting input. Specifications subject to change without notice. –2– REV. A AD8047/AD8048 ABSOLUTE MAXIMUM RATINGS 1 MAXIMUM POWER DISSIPATION Supply Voltage, (+VS) – (–VS) . . . . . . . . . . . . . . . . . . . . 12.6 V Voltage Swing × Bandwidth Product AD8047 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180 V-MHz AD8048 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 250 V-MHz Internal Power Dissipation2 Plastic Package (N) . . . . . . . . . . . . . . . . . . . . . . . . . . 1.3 W Small Outline Package (R) . . . . . . . . . . . . . . . . . . . . . 0.9 W Input Voltage (Common Mode) . . . . . . . . . . . . . . . . . . . . ± VS Differential Input Voltage . . . . . . . . . . . . . . . . . . . . . . ± 1.2 V Output Short-Circuit Duration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Observe Power Derating Curves Storage Temperature Range (N, R) . . . . . . . –65°C to +125°C Operating Temperature Range (A Grade) . . . –40°C to +85°C Lead Temperature Range (Soldering 10 sec) . . . . . . . . . 300°C The maximum power that can be safely dissipated by these devices is limited by the associated rise in junction temperature. The maximum safe junction temperature for plastic encapsulated devices is determined by the glass transition temperature of the plastic, approximately 150°C. Exceeding this limit temporarily may cause a shift in parametric performance due to a change in the stresses exerted on the die by the package. Exceeding a junction temperature of 175°C for an extended period can result in device failure. While the AD8047 and AD8048 are internally short circuit protected, this may not be sufficient to guarantee that the maximum junction temperature (150°C) is not exceeded under all conditions. To ensure proper operation, it is necessary to observe the maximum power derating curves. NOTES 1 Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. This is a stress rating only; functional operation of the device at these or any other conditions above those indicated in the operational section of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. 2 Specification is for device in free air: 8-Lead PDIP Package, JA = 90°C/W; 8-Lead SOIC Package, JA = 140°C/W 2.0 MAXIMUM POWER DISSIPATION (W) 8-PIN PDIP PACKAGE METALLIZATION PHOTOS Dimensions shown in inches and (mm) Connect Substrate to –V S. AD8047 +VS TJ = +150C 1.5 1.0 8-PIN SOIC PACKAGE 0.5 0 –50 –40 –30 –20 –10 0 10 20 30 40 50 60 AMBIENT TEMPERATURE (C) 0.045 (1.14) 70 80 90 Figure 2. Plot of Maximum Power Dissipation vs. Temperature VOUT –IN ORDERING GUIDE –VS +IN 0.044 (1.13) AD8048 +VS 0.045 (1.14) VOUT Model Temperature Range Package Description Package Option* AD8047AN AD8047AR AD8047AR-REEL AD8047AR-REEL7 AD8048AN AD8048AR AD8048AR-REEL AD8048AR-REEL7 –40°C to +85°C –40°C to +85°C –40°C to +85°C –40°C to +85°C –40°C to +85°C –40°C to +85°C –40°C to +85°C –40°C to +85°C PDIP SOIC SOIC SOIC PDIP SOIC SOIC SOIC N-8 R-8 R-8 R-8 N-8 R-8 R-8 R-8 *N = PDIP, R= SOIC –IN –VS +IN 0.044 (1.13) CAUTION ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on the human body and test equipment and can discharge without detection. Although the AD8047/AD8048 features proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance degradation or loss of functionality. REV. A –3– AD8047/AD8048–Typical Performance Characteristics RF PULSE GENERATOR 10F +VS TR/TF = 500ps 0.1F PULSE GENERATOR 2 TR/TF = 500ps 3 VOUT 6 0.1F 4 RT = 49.9 2 VIN AD8047 VIN 0.1F RIN 7 3 RL = 100 4 RL = 100 10F –VS TPC 1. AD8047 Noninverting Configuration, G = +1 TPC 4. AD8047 Inverting Configuration, G = –1 5ns 1V TPC 2. AD8047 Large Signal Transient Response; VO = 4 V p-p, G = +1 100mV VOUT 6 0.1F 100 –VS 1V 7 AD8047 RT = 66.5 10F 10F +VS 5ns TPC 5. AD8047 Large Signal Transient Response; VO = 4 V p-p, G = –1, RF = RIN = 200 Ω 100mV 5ns TPC 3. AD8047 Small Signal Transient Response; VO = 400 mV p-p, G = +1 5ns TPC 6. AD8047 Small Signal Transient Response; VO = 400 mV p-p, G = –1, RF = RIN = 200 Ω –4– REV. A AD8047/AD8048 RF PULSE GENERATOR 10F +VS TR/TF = 500ps PULSE GENERATOR 2 2 VIN VOUT 6 3 4 RL = 100 RL = 100 –VS TPC 7. AD8048 Noninverting Configuration, G = +2 TPC 10. AD8048 Inverting Configuration, G= –1 1V 5ns TPC 8. AD8048 Large Signal Transient Response; VO = 4 V p-p, G = +2, RF = RIN = 200 Ω 5ns TPC 11. AD8048 Large Signal Transient Response; VO = 4 V p-p, G = –1, RF = RIN = 200 Ω 100mV 5ns TPC 9. AD8048 Small Signal Transient Response; VO = 400 mV p-p, G = +2, RF = RIN = 200 Ω REV. A 4 10F –VS 100mV VOUT 6 0.1F RS = 100 10F 1V 7 AD8048 RT = 66.5 0.1F RT = 49.9 10F 0.1F RIN 7 AD8048 3 +VS TR/TF = 500ps 0.1F RIN VIN RF 5ns TPC 12. AD8048 Small Signal Transient Response; VO = 400 mV p-p, G = –1, RF = RIN = 200 Ω –5– AD8047/AD8048 1 1 0 0 –1 –1 RL = 100 RF = 0 FOR DIP RF = 66.5 FOR SOIC VOUT = 300mV p-p –3 –2 OUTPUT (dBm) OUTPUT (dBm) –2 –4 –5 –3 –4 –5 –6 –6 –7 –7 –8 –8 –9 1M 10M 100M RL = 100 RF = 0 FOR DIP RF = 66.5 FOR SOIC VOUT = 2V p-p –9 1M 1G 10M FREQUENCY (Hz) TPC 13. AD8047 Small Signal Frequency Response, G = +1 1 0 0 RL = 100 RF = 0 FOR DIP RF = 66.5 FOR SOIC VOUT = 300mV p-p –1 –2 OUTPUT (dBm) OUTPUT (dBm) –0.2 –0.3 –0.4 –0.5 –4 –5 –6 –0.7 –7 –0.8 –8 10M 100M RL = 100 RF = RF = 200 VOUT = 300mV p-p –3 –0.6 –0.9 1M –9 1M 1G 10M FREQUENCY (Hz) 100 60 80 PHASE MARGIN 20 30 GAIN 0 –20 10 –40 0 RL = 100 –40 1k 10k 100k 1M 10M 100M –70 SECOND HARMONIC –80 THIRD HARMONIC –100 –80 –30 –60 –90 –60 –20 RL = 1k VOUT = 2V p-p –50 OUTPUT (dBm) 40 PHASE MARGIN (Degrees) GAIN (dB) –20 –30 60 40 –10 1G TPC 17. AD8047 Small Signal Frequency Response, G = –1 70 20 100M FREQUENCY (Hz) TPC 14. AD8047 0.1 dB Flatness, G = +1 50 1G TPC 16. AD8047 Large Signal Frequency Response, G = +1 0.1 –0.1 100M FREQUENCY (Hz) –110 –100 1G –120 10k FREQUENCY (Hz) 100k 1M 10M 100M FREQUENCY (Hz) TPC 15. AD8047 Open-Loop Gain and Phase Margin vs. Frequency TPC 18. AD8047 Harmonic Distortion vs. Frequency, G = +1 –6– REV. A AD8047/AD8048 0.5 –20 RL = 100 VOUT = 2V p-p –40 0.3 –50 0.2 –60 –70 RL = 100 RF = 0 VOUT = 2V STEP 0.4 ERROR (%) HARMONIC DISTORTION (dBc) –30 SECOND HARMONIC –80 0.1 0.0 –0.1 –0.2 –90 THIRD HARMONIC –0.3 –100 –110 –0.4 –120 10k –0.5 100k 10M 1M 100M 0 5 10 FREQUENCY (Hz) –25 0.15 0.10 –40 ERROR (%) HARMONIC DISTORTION (dBc) 45 RL = 100 RF = 0 VOUT = 2V STEP 0.20 –35 –45 THIRD HARMONIC –50 0.05 0.00 –0.05 –0.10 –55 –0.15 SECOND HARMONIC –0.20 –65 1.5 2.5 3.5 4.5 5.5 –0.25 6.5 0 2 4 OUTPUT SWING (V p-p) TPC 20. AD8047 Harmonic Distortion vs. Output Swing, G = +1 6 10 12 8 SETTLING TIME (s) 14 16 18 TPC 23. AD8047 Long-Term Settling Time, G = +1 0.04 17 0.02 15 INPUT NOISE VOLTAGE (nV/√Hz) DIFF GAIN (%) 40 0.25 f = 200MHz RL = 1k RF = 0 FOR SOIC –60 0.00 –0.02 –0.04 1st DIFF PHASE (Degrees) 35 TPC 22. AD8047 Short-Term Settling Time, G = +1 TPC 19. AD8047 Harmonic Distortion vs. Frequency, G = +1 –30 15 25 30 20 SETTLING TIME (ns) 2nd 3rd 4th 5th 6th 7th 8th 9th 10th 11th 0.04 0.02 0.00 13 11 9 7 5 –0.02 –0.04 1st 2nd 3rd 4th 5th 6th 7th 8th 9th 3 10th 11th 10 100 1k 10k FREQUENCY (Hz) TPC 21. AD8047 Differential Gain and Phase Error, G = +2, RL = 150 Ω, RF = 200 Ω, RIN = 200 Ω REV. A TPC 24. AD8047 Noise vs. Frequency –7– 100k AD8047/AD8048 7 7 6 6 RL = 100 RF = RIN = 200 VOUT = 300mV p-p OUTPUT (dBm) 4 5 OUTPUT (dBm) 5 3 2 1 4 3 2 1 0 0 –1 –1 –2 –2 –3 –3 1M 10M 100M FREQUENCY (Hz) 1M 1G 10M 1G TPC 28. AD8048 Large Signal Frequency Response, G = +2 6.5 1 6.4 0 RL = 100 RF = RIN = 200 VOUT = 300mV p-p 6.3 –1 OUTPUT (dBm) 6.2 6.1 6.0 5.9 –2 –4 –5 –6 5.7 –7 5.6 –8 1M 10M 100M RL = 100 RF = RIN = 200 VOUT = 300mV p-p –3 5.8 5.5 –9 1M 1G 10M FREQUENCY (Hz) TPC 26. AD8048 0.1 dB Flatness, G = +2 100 –20 80 80 –30 70 60 HARMONIC DISTORTION (dBc) 90 40 50 20 40 0 –20 RL = 100 20 –40 PHASE (Degrees) 60 30 –60 10 –80 0 –10 –100 –20 –120 1G 1k 10k 100k 1M 10M FREQUENCY (Hz) 100M 100M FREQUENCY (Hz) 1G TPC 29. AD8048 Small Signal Frequency Response, G = –1 PHASE GAIN (dB) 100M FREQUENCY (Hz) TPC 25. AD8048 Small Signal Frequency Response, G = +2 OUTPUT (dBm) RL = 100 RF = RIN = 200 VOUT = 2V p-p –40 RL = 1k VOUT = 2V p-p –50 –60 –70 SECOND HARMONIC –80 –90 THIRD HARMONIC –100 –110 –120 10k 100k 1M FREQUENCY (Hz) 10M 100M TPC 30. AD8048 Harmonic Distortion vs. Frequency, G = +2 TPC 27. AD8048 Open-Loop Gain and Phase Margin vs. Frequency –8– REV. A AD8047/AD8048 0.5 –20 RL = 100 VOUT = 2V p-p 0.4 –40 0.3 –50 0.2 –60 0.1 –70 ERROR (%) HARMONIC DISTORTION (dBc) –30 SECOND HARMONIC –80 0.0 –0.1 THIRD HARMONIC –90 –0.2 –100 –0.3 –110 –0.4 –0.5 –120 10k 100k 10M 1M FREQUENCY (Hz) 100M 0 5 10 25 30 35 40 0.20 f = 20MHz RL = 1k RF = 200 –25 –30 RL = 100 RF = 200 VOUT = 2V STEP 0.15 THIRD HARMONIC 0.10 ERROR (%) –35 –40 –45 0.05 0.0 –0.05 –50 SECOND HARMONIC –0.10 –55 –0.15 –60 –0.20 –65 –70 1.5 2.5 3.5 4.5 5.5 –0.25 6.5 0 2 4 OUTPUT SWING (V p-p) TPC 32. AD8048 Harmonic Distortion vs. Output Swing, G = +2 6 10 12 8 SETTLING TIME (s) 14 16 18 TPC 35. AD8048 Long-Term Settling Time 2 V Step, G = +2 17 0.04 0.02 INPUT NOISE VOLTAGE (nV/√Hz) 15 0.00 –0.02 –0.04 1st 2nd 3rd 4th 5th 6th 7th 8th 9th 10th 11th 0.04 0.02 0.00 13 11 9 7 5 –0.02 3 –0.04 1st 2nd 3rd 4th 5th 6th 7th 8th 9th 10th 11th 10 100 1k 10k FREQUENCY (Hz) TPC 33. AD8048 Differential Gain and Phase Error, G = +2, RL = 150 Ω, RF = 200 Ω, RIN = 200 Ω REV. A 45 0.25 –20 DIFF GAIN (%) 20 TPC 34. AD8048 Short-Term Settling Time, G = +2 –15 DIFF PHASE (Degrees) 15 SETTLING TIME (ns) TPC 31. AD8048 Harmonic Distortion vs. Frequency, G = +2 HARMONIC DISTORTION (dBc) RL = 100 RF = 200 VOUT = 2V STEP TPC 36. AD8048 Noise vs. Frequency –9– 100k AD8047/AD8048 100 100 VCM = 1V RL = 100 80 80 70 70 60 60 50 50 40 40 30 30 20 100k 1M 10M 100M VCM = 1V RL = 100 90 CMRR (dB) CMRR (dB) 90 20 100k 1G 1M FREQUENCY (Hz) 100M 1G TPC 40. AD8048 CMRR vs. Frequency 100 100 10 10 ROUT () ROUT () TPC 37. AD8047 CMRR vs. Frequency 10M FREQUENCY (Hz) 1 0.1 1 0.1 0.01 10k 100k 1M 10M 100M 0.01 10k 1G 100k 1M 10M 100M 1G FREQUENCY (Hz) FREQUENCY (Hz) TPC 38. AD8047 Output Resistance vs. Frequency, G = +1 TPC 41. AD8048 Output Resistance vs. Frequency, G = +2 90 90 80 80 –PSRR +PSRR 70 +PSRR –PSRR 60 PSRR (dB) PSRR (dB) 60 70 50 40 50 40 30 30 20 20 10 10 0 10k 100k 1M 10M 100M 0 1G 3k FREQUENCY (Hz) 10k 100k 1M 100M 500M FREQUENCY (Hz) TPC 39. AD8047 PSRR vs. Frequency TPC 42. AD8048 PSRR vs. Frequency, G = +2 –10– REV. A AD8047/AD8048 4.1 83.0 3.9 RL = 1k +VOUT 82.0 AD8047 3.7 OUTPUT SWING (V) –VOUT 81.0 CMRR (–dB) 3.5 3.3 +VOUT RL = 150 3.1 –VOUT 80.0 AD8048 79.0 2.9 78.0 2.7 +VOUT 2.5 2.3 –60 –40 –20 77.0 RL = 50 –VOUT 0 20 40 60 80 100 JUNCTION TEMPERATURE (C) 120 76.0 –60 140 –40 –20 0 20 40 60 80 100 120 140 JUNCTION TEMPERATURE (C) TPC 43. AD8047/AD8048 Output Swing vs. Temperature TPC 46. AD8047/AD8048 CMRR vs. Temperature 2600 8.0 2400 7.5 AD8048 SUPPLY CURRENT (mA) OPEN-LOOP GAIN (V/V) AD8048 2200 2000 1800 1600 1400 6V 6.5 AD8048 6.0 5V 5.0 –40 –20 0 20 40 60 80 100 120 4.5 –60 140 –40 –20 JUNCTION TEMPERATURE (C) 92 800 PSRR (–dB) INPUT OFFSET VOLTAGE (V) 900 +PSRR 88 AD8048 86 84 –PSRR AD8048 +PSRR AD8047 82 80 78 –PSRR –20 0 20 40 60 80 100 120 700 60 80 100 120 140 AD8048 600 AD8047 500 400 300 100 –60 140 JUNCTION TEMPERATURE (C) TPC 45. AD8047/AD8048 PSRR vs. Temperature REV. A 40 200 AD8047 –40 20 TPC 47. AD8047/AD8048 Supply Current vs. Temperature 94 90 0 JUNCTION TEMPERATURE (C) TPC 44. AD8047/AD8048 Open-Loop Gain vs. Temperature 76 –60 AD8047 5V 5.5 AD8047 1200 1000 –60 AD8047 6V 7.0 –40 –20 0 20 40 60 80 100 JUNCTION TEMPERATURE (C) 120 140 TPC 48. AD8047/AD8048 Input Offset Voltage vs. Temperature –11– AD8047/AD8048 For general voltage gain applications, the amplifier bandwidth can be closely estimated as ωO f 3 dB ≅ R 2π 1+ F RG THEORY OF OPERATION General The AD8047 and AD8048 are wide bandwidth, voltage feedback amplifiers. Since their open-loop frequency response follows the conventional 6 dB/octave roll-off, their gain bandwidth product is basically constant. Increasing their closed-loop gain results in a corresponding decrease in small signal bandwidth. This can be observed by noting the bandwidth specification between the AD8047 (gain of 1) and AD8048 (gain of 2). This estimation loses accuracy for gains of +2/–1 or lower due to the amplifier’s damping factor. For these low gain cases, the bandwidth will actually extend beyond the calculated value (see Closed-Loop BW plots, TPCs 13 and 25). Feedback Resistor Choice The value of the feedback resistor is critical for optimum performance on the AD8047 and AD8048. For maximum flatness at a gain of 2, RF and RG should be set to 200 Ω for the AD8048. When the AD8047 is configured as a unity gain follower, RF should be set to 0 Ω (no feedback resistor should be used) for the plastic DIP and 66.5 Ω for the SOIC. G = 1+ where NG is the Noise Gain (1 + RF/RG) of the circuit. For most voltage gain applications, this should be the case. RF 10F +VS RF As a general rule, capacitor CF will not be required if NG (RF RG ) × CI ≤ 4 ωO RG VIN 7 3 RTERM 2 CF 0.1F AD8047/ AD8048 VOUT 6 0.1F 4 II RG –VS CI AD8047 VOUT 10F RF Figure 5. Transimpedance Configuration Figure 3. Noninverting Operation Pulse Response G= – RF 7 3 RG RG VIN 0.1F AD8047/ AD8048 2 RTERM 4 –VS Unlike a traditional voltage feedback amplifier, where the slew speed is dictated by its front end dc quiescent current and gain bandwidth product, the AD8047 and AD8048 provide on demand current that increases proportionally to the input step signal amplitude. This results in slew rates (1000 V/µs) comparable to wideband current feedback designs. This, combined with relatively low input noise current (1.0 pA/√Hz), gives the AD8047 and AD8048 the best attributes of both voltage and current feedback amplifiers. 10F +VS VOUT 6 0.1F 10F RF Large Signal Performance Figure 4. Inverting Operation When the AD8047 is used in the transimpedance (I to V) mode, such as in photodiode detection, the values of RF and diode capacitance (CI) are usually known. Generally, the value of RF selected will be in the kΩ range, and a shunt capacitor (CF) across RF will be required to maintain good amplifier stability. The value of CF required to maintain optimal flatness (<1 dB peaking) and settling time can be estimated as [ 2 CF ≅ (2 ωO CI RF – 1)/ωO RF 2 ] 1/2 where O is equal to the unity gain bandwidth product of the amplifier in rad/sec, and CI is the equivalent total input capacitance at the inverting input. Typically, O = 800 × 106 rad/sec (see Open-Loop Frequency Response curve, TPC 15). As an example, choosing RF = 10 kΩ and CI = 5 pF requires CF to be 1.1 pF (Note: CI includes both source and parasitic circuit capacitance). The bandwidth of the amplifier can be estimated using the CF calculated as f 3 dB 1.6 ≅ 2πR F CF The outstanding large signal operation of the AD8047 and AD8048 is due to a unique, proprietary design architecture. In order to maintain this level of performance, the maximum 180 V-MHz product must be observed (e.g., @ 100 MHz, VO ≤ 1.8 V p-p) on the AD8047 and the 250 V-MHz product must be observed on the AD8048. Power Supply Bypassing Adequate power supply bypassing can be critical when optimizing the performance of a high frequency circuit. Inductance in the power supply leads can form resonant circuits that produce peaking in the amplifier’s response. In addition, if large current transients must be delivered to the load, then bypass capacitors (typically greater than 1 µF) will be required to provide the best settling time and lowest distortion. A parallel combination of at least 4.7 µF, and between 0.1 µF and 0.01 µF, is recommended. Some brands of electrolytic capacitors will require a small series damping resistor ≈4.7 Ω for optimum results. Driving Capacitive Loads The AD8047/AD8048 have excellent cap load drive capability for high speed op amps, as shown in Figures 7 and 9. However, when driving cap loads greater than 25 pF, the best frequency response is obtained by the addition of a small series resistance. –12– REV. A AD8047/AD8048 It is worth noting that the frequency response of the circuit when driving large capacitive loads will be dominated by the passive roll-off of RSERIES and CL. margin (65°), low noise current (1.0 pA/√Hz), and slew rate (1000 V/µs) give higher performance capabilities to these applications over previous voltage feedback designs. With a settling time of 30 ns to 0.01% and 13 ns to 0.1%, the devices are an excellent choice for DAC I/V conversion. The same characteristics along with low harmonic distortion make them a good choice for ADC buffering/amplification. With superb linearity at relatively high signal frequencies, the AD8047 and AD8048 are ideal drivers for ADCs up to 12 bits. RF AD8047 RSERIES RL 1k CL Operation as a Video Line Driver The AD8047 and AD8048 have been designed to offer outstanding performance as video line drivers. The important specifications of differential gain (0.01%) and differential phase (0.02°) meet the most exacting HDTV demands for driving video loads. Figure 6. Driving Capacitive Loads 200 200 10F +VS 0.1F 7 2 3 VIN 500mV 5ns 75 AD8047/ AD8048 75 CABLE 75 CABLE 6 0.1F 75 4 75 VOUT 10F –VS Figure 7. AD8047 Large Signal Transient Response; VO = 2 V p-p, G = +1, RF = 0 Ω, RSERIES = 0 Ω, CL = 27 pF Figure 10. Video Line Driver Active Filters RF RIN AD8048 The wide bandwidth and low distortion of the AD8047 and AD8048 are ideal for the realization of higher bandwidth active filters. These characteristics, while being more common in many current feedback op amps, are offered in the AD8047 and AD8048 in a voltage feedback configuration. Many active filter configurations are not realizable with current feedback amplifiers. RSERIES RL 1k CL A multiple feedback active filter requires a voltage feedback amplifier and is more demanding of op amp performance than other active filter configurations such as the Sallen-Key. In general, the amplifier should have a bandwidth that is at least 10 times the bandwidth of the filter if problems due to phase shift of the amplifier are to be avoided. Figure 8. Driving Capacitive Loads Figure 11 is an example of a 20 MHz low-pass multiple feedback active filter using an AD8048. C1 50pF R4 154 500mV VIN 5ns R1 154 R3 78.7 C2 100pF Figure 9. AD8048 Large Signal Transient Response; VO = 2 V p-p, G = +2, RF = RIN = 200 Ω, RSERIES = 0 Ω, CL = 27 pF 0.1F 1 7 2 AD8048 3 6 5 0.1F 4 100 10F –5V Figure 11. Active Filter Circuit APPLICATIONS The AD8047 and AD8048 are voltage feedback amplifiers well suited for such applications as photodetectors, active filters, and log amplifiers. The devices’ wide bandwidth (260 MHz), phase REV. A 10F +5V –13– VOUT AD8047/AD8048 Choose Layout Considerations FO = Cutoff Frequency = 20 MHz ␣ = Damping Ratio = 1/Q = 2 The specified high speed performance of the AD8047 and AD8048 requires careful attention to board layout and component selection. Proper RF design techniques and low-pass parasitic component selection are mandatory. H = Absolute Value of Circuit Gain = –R4 = 1 R1 Then, The PCB should have a ground plane covering all unused portions of the component side of the board to provide a low impedance path. The ground plane should be removed from the area near the input pins to reduce stray capacitance. k = 2 π FO C1 4 C1(H +1) α2 α R1 = 2 HK C2 = R3 = Chip capacitors should be used for the supply bypassing (see Figure 12). One end should be connected to the ground plane and the other within 1/8 inch of each power pin. An additional large (0.47 µF to 10 µF) tantalum electrolytic capacitor should be connected in parallel, though not necessarily so close, to the supply current for fast, large signal changes at the output. α 2 K (H +1) R4 = H(R1) The feedback resistor should be located close to the inverting input pin in order to keep the stray capacitance at this node to a minimum. Capacitance variations of less than 1 pF at the inverting input will significantly affect high speed performance. A/D Converter Driver As A/D converters move toward higher speeds with higher resolutions, there becomes a need for high performance drivers that will not degrade the analog signal to the converter. It is desirable from a system’s standpoint that the A/D be the element in the signal chain that ultimately limits overall distortion. This places new demands on the amplifiers used to drive fast, high resolution A/Ds. Stripline design techniques should be used for long signal traces (greater than about 1 inch). These should be designed with a characteristic impedance of 50 Ω or 75 Ω and be properly terminated at each end. With high bandwidth, low distortion, and fast settling time, the AD8047 and AD8048 make high performance A/D drivers for advanced converters. Figure 12 is an example of an AD8047 used as an input driver for an AD872A, a 12-bit, 10 MSPS A/D converter. +5V DIGITAL +5V ANALOG 10 7 DVDD 4 0.1F +5V ANALOG 5 6 DGND +5V DIGITAL AVDD 22 DRVDD AGND 23 DRGND 10F AD872A 0.1F AD8047 ANALOG IN 3 1 6 MSB BIT2 BIT3 BIT4 BIT5 BIT6 BIT7 BIT8 BIT9 BIT10 BIT11 BIT12 VINA 0.1F 4 2 10F VINB 27 –5V ANALOG REF GND 0.1F 28 REF IN 26 1F 19 18 17 16 15 14 13 12 11 10 9 8 AGND REF OUT AVSS 20 OTR 7 0.1F CLOCK INPUT 21 CLK 2 0.1F 49.9 DIGITAL OUTPUT 24 AVSS 3 0.1F 25 0.1F –5V ANALOG Figure 12. AD8047 Used as Driver for an AD872A, a 12-Bit, 10 MSPS A/D Converter –14– REV. A AD8047/AD8048 OUTLINE DIMENSIONS 8-Lead Plastic Dual In-Line Package [PDIP] (N-8) Dimensions shown in inches and (millimeters) 0.375 (9.53) 0.365 (9.27) 0.355 (9.02) 8 5 1 4 0.295 (7.49) 0.285 (7.24) 0.275 (6.98) 0.325 (8.26) 0.310 (7.87) 0.300 (7.62) 0.100 (2.54) BSC 0.015 (0.38) MIN 0.180 (4.57) MAX 0.150 (3.81) 0.130 (3.30) 0.110 (2.79) 0.022 (0.56) 0.018 (0.46) 0.014 (0.36) 0.150 (3.81) 0.135 (3.43) 0.120 (3.05) 0.015 (0.38) 0.010 (0.25) 0.008 (0.20) SEATING PLANE 0.060 (1.52) 0.050 (1.27) 0.045 (1.14) COMPLIANT TO JEDEC STANDARDS MO-095AA CONTROLLING DIMENSIONS ARE IN INCHES; MILLIMETER DIMENSIONS (IN PARENTHESES) ARE ROUNDED-OFF INCH EQUIVALENTS FOR REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN 8-Lead Standard Small Outline Package [SOIC] (R-8) Dimensions shown in millimeters and (inches) 5.00 (0.1968) 4.80 (0.1890) 4.00 (0.1574) 3.80 (0.1497) 8 5 1 4 1.27 (0.0500) BSC 0.25 (0.0098) 0.10 (0.0040) COPLANARITY SEATING 0.10 PLANE 6.20 (0.2440) 5.80 (0.2284) 1.75 (0.0688) 1.35 (0.0532) 0.51 (0.0201) 0.31 (0.0122) 0.50 (0.0196) 45 0.25 (0.0099) 8 0.25 (0.0098) 0 1.27 (0.0500) 0.40 (0.0157) 0.17 (0.0067) COMPLIANT TO JEDEC STANDARDS MS-012AA CONTROLLING DIMENSIONS ARE IN MILLIMETERS; INCH DIMENSIONS (IN PARENTHESES) ARE ROUNDED-OFF MILLIMETER EQUIVALENTS FOR REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN REV. A –15– AD8047/AD8048 Revision History Location Page 7/03—Data Sheet changed from REV. 0 to REV. A. Deleted Evaluation Board Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Universal Updated ORDERING GUIDE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Updated OUTLINE DIMENSIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 –16– REV. A C01061–0–7/03(A) Renumbered Figures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Universal