AD9631AN

a FEATURES Wide Bandwidth AD9631, G = +1 AD9632, G = +2 Small Signal 320 MHz 250 MHz Large Signal (4 V p-p) 175 MHz 180 MHz Ultralow Distortion (SFDR), Low Noise –113 dBc Typ @ 1 MHz –95 dBc Typ @ 5 MHz –72 dBc Typ @ 20 MHz 46 dBm Third Order Intercept @ 25 MHz 7.0 nV/÷Hz Spectral Noise Density High Speed Slew Rate 1300 V/ s Settling 16 ns to 0.01%, 2 V Step 3 V to 5 V Supply Operation 17 mA Supply Current APPLICATIONS ADC Input Driver Differential Amplifiers IF/RF Amplifiers Pulse Amplifiers Professional Video DAC Current to Voltage Baseband and Video Communications Pin Diode Receivers Active Filters/Integrators/Log Amps Ultralow Distortion, Wide Bandwidth Voltage Feedback Op Amps AD9631/AD9632 PIN CONFIGURATION 8-Lead PDIP (N) and SOIC (R) Packages AD9631/ AD9632 NC 1 –INPUT +INPUT 2 3 8 NC 7 +VS 6 OUTPUT –VS 4 TOP VIEW 5 NC NC = NO CONNECT A proprietary design architecture has produced an amplifier that combines many of the best characteristics of both current feedback and voltage feedback amplifiers. The AD9631 and AD9632 exhibit exceptionally fast and accurate pulse response (16 ns to 0.01%) as well as extremely wide small signal and large signal bandwidth and ultralow distortion. The AD9631 achieves –72 dBc at 20 MHz, and 320 MHz small signal and 175 MHz large signal bandwidths. These characteristics position the AD9631/AD9632 ideally for driving flash as well as high resolution ADCs. Additionally, the balanced high impedance inputs of the voltage feedback architecture allow maximum flexibility when designing active filters. The AD9631/AD9632 are offered in the industrial (–40 C to +85 C) temperature range. They are available in PDIP and SOIC. –30 VS = 5V RL = 500 VO = 2V p-p HARMONIC DISTORTION – dBc –50 –70 GENERAL DESCRIPTION The AD9631 and AD9632 are very high speed and wide bandwidth amplifiers. They are an improved performance alternative to the AD9621 and AD9622. The AD9631 is unity gain stable. The AD9632 is stable at gains of 2 or greater. Using a voltage feedback architecture, the AD9631/AD9632’s exceptional settling time, bandwidth, and low distortion meet the requirements of many applications that previously depended on current feedback amplifiers. Its classical op amp structure works much more predictably in many designs. –90 SECOND HARMONIC –110 THIRD HARMONIC –130 10k 100k 1M FREQUENCY – Hz 10M 100M Figure 1. AD9631 Harmonic Distortion vs. Frequency, G = +1 REV. C 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. AD9631/AD9632–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 Third Order Intercept Noise Figure Input Voltage Noise Input Current Noise Average Equivalent Integrated Input Noise Voltage Differential Gain Error (3.58 MHz) Differential Phase Error (3.58 MHz) Phase Nonlinearity DC PERFORMANCE2, RL = 150 W Input Offset Voltage3 TMIN–TMAX Offset Voltage Drift Input Bias Current TMIN–TMAX Input Offset Current Common-Mode Rejection Ratio Open-Loop Gain INPUT CHARACTERISTICS Input Resistance Input Capacitance Input Common-Mode Voltage Range OUTPUT CHARACTERISTICS Output Voltage Range, RL = 150 W Output Current Output Resistance Short Circuit Current POWER SUPPLY Operating Range Quiescent Current Power Supply Rejection Ratio TMIN–TMAX TMIN–TMAX TMIN–TMAX VCM = ± 2.5 V VOUT = ± 2.5 V TMIN–TMAX 70 46 40 0.1 90 52 ( VS = 5 V; RLOAD = 100 ; AV = 1 (AD9631); AV = 2 (AD9632), unless otherwise noted.) AD9631A Min Typ Max AD9632A Min Typ Max Unit Conditions VOUT 0.4 V p-p VOUT = 4 V p-p VOUT = 300 mV p-p AD9631, RF = 140 W; AD9632, RF = 425 W VOUT = 4 V Step VOUT = 0.5 V Step VOUT = 4 V Step VOUT = 2 V Step VOUT = 2 V Step 2 V p-p; 20 MHz, RL = 100 W RL = 500 W 2 V p-p; 20 MHz, RL = 100 W RL = 500 W 25 MHz RS = 50 W 1 MHz to 200 MHz 1 MHz to 200 MHz 0.1 MHz to 200 MHz RL = 150 W RL = 150 W DC to 100 MHz 220 150 320 175 130 180 155 250 180 130 MHz MHz MHz V/ms ns ns ns ns –47 –65 –67 –74 dBc dBc dBc dBc dBm dB nV/÷Hz pA/÷Hz mV rms % Degree Degree mV mV mV/ C mA mA mA mA dB dB dB kW pF V V mA W mA V mA mA dB 1000 1300 1.2 2.5 11 16 –64 –72 –76 –81 46 18 7.0 2.5 100 0.03 0.02 1.1 3 ± 10 2 –57 –65 –69 –74 1200 1500 1.4 2.1 11 16 –54 –72 –74 –81 41 14 4.3 2.0 0.06 0.04 60 0.02 0.04 0.02 0.04 1.1 2 5 8 10 13 7 10 3 5 70 46 40 ± 10 2 7 10 0.1 3 5 90 52 500 1.2 ± 3.4 ± 3.2 ± 3.9 70 0.3 240 ± 3.0 ± 5.0 ± 6.0 17 18 21 50 60 500 1.2 ± 3.4 ± 3.2 ± 3.9 70 0.3 240 ± 3.0 ± 5.0 ± 6.0 16 17 20 56 66 NOTES 1 See Absolute Maximum Ratings and Theory of Operation sections of this data sheet. 2 Measured at AV = 50. 3 Measured with respect to the inverting input. Specifications subject to change without notice. –2– R EV. C AD9631/AD9632 ABSOLUTE MAXIMUM RATINGS 1 MAXIMUM POWER DISSIPATION Supply Voltage (+VS to –VS) . . . . . . . . . . . . . . . . . . . . . 12.6 V Voltage Swing ¥ Bandwidth Product . . . . . . . . . . . 550 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 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: qJA = 90∞C/W 8-Lead SOIC Package: qJA = 140∞C/W 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 AD9631 and AD9632 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. 2.0 TJ = +150 C MAXIMUM POWER DISSIPATION – W 8-LEAD PDIP PACKAGE 1.5 METALLIZATION PHOTO Dimensions shown in inches and (millimeters) Connect Substrate to –V S –IN 2 +VS 7 1.0 8-LEAD SOIC PACKAGE 0.5 0 –50 –40 –30 –20 –10 0.046 (1.17) 0 10 20 30 40 50 60 70 80 90 AMBIENT TEMPERATURE – C 6 OUT Figure 2. Maximum Power Dissipation vs. Temperature ORDERING GUIDE 3 +IN –IN 2 4 –VS 0.050 (1.27) AD9631 +VS 7 Model AD9631AN AD9631AR AD9631AR-REEL AD9631AR-REEL7 AD9631CHIPS AD9632AN AD9632AR AD9632AR-REEL AD9632AR-REEL7 Temperature Range –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 Package Package Description Option PDIP SOIC SOIC SOIC Die PDIP SOIC SOIC SOIC N-8 R-8 R-8 R-8 N-8 R-8 R-8 R-8 0.046 (1.17) 6 OUT 3 +IN 4 –VS AD9632 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 AD9631/AD9632 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. R EV. C –3– AD9631/AD9632–Typical Performance Characteristics RF +VS 10 F 0.1 F PULSE GENERATOR TR /TF = 350ps VIN RT 49.9 PULSE GENERATOR TR /TF = 350ps VIN 267 RT 49.9 RF +VS 10 F 0.1 F AD9631 130 0.1 F 10 F –VS VOUT RL = 100 AD9631 0.1 F VOUT RL = 100 100 10 F –VS TPC 1. AD9631 Noninverting Configuration, G = +1 TPC 4. AD9631 Inverting Configuration, G = –1 1V 5ns 1V 5ns TPC 2. AD9631 Large Signal Transient Response; VO = 4 V p-p, G = +1, RF = 250 W TPC 5. AD9631 Large Signal Transient Response; VO = 4 V p-p, G = –1, RF = RIN = 267 W 100mV 5ns 100mV 5ns TPC 3. AD9631 Small Signal Transient Response; VO = 400 mV p-p, G = +1, RF = 140 W TPC 6. AD9631 Small Signal Transient Response; VO = 400 mV p-p, G = –1, RF = RIN = 267 W –4– R EV. C AD9631/AD9632 RF PULSE GENERATOR TR /TF = 350ps RIN +VS 10 F 0.1 F PULSE GENERATOR TR /TF = 350ps VIN R IN RF +VS 10 F 0.1 F AD9632 130 VIN RT 49.9 0.1 F 10 F –VS VOUT RL = 100 RT 49.9 AD9632 0.1 F VOUT RL = 100 100 10 F –VS TPC 7. AD9632 Noninverting Configuration, G = +2 TPC 10. AD9632 Inverting Configuration, G = –1 1V 5ns 1V 5ns TPC 8. AD9632 Large Signal Transient Response; VO = 4 V p-p, G = +2, RF = RIN = 422 W TPC 11. AD9632 Large Signal Transient Response; VO = 4 V p-p, G = –1, RF = RIN = 422 W, RT = 56.2 W 100mV 5ns 100mV 5ns TPC 9. AD9632 Small Signal Transient Response; VO = 400 mV p-p, G = +2, RF = RIN = 274 W TPC 12. AD9632 Small Signal Transient Response; VO = 400 mV p-p, G = –1, RF = RIN = 267 W, RT = 61.9 W R EV. C –5– AD9631/AD9632 1 0 –1 –2 GAIN – dB RF 150 VS = 5V RL = 100 VO = 300mV p-p RF 200 450 VS = 5V RL = 100 GAIN = +1 RF –3dB BANDWIDTH – MHz RF 50 RF 100 400 AD9631 130 RL –3 –4 –5 –6 –7 –8 –9 1M N PACKAGE 350 300 R PACKAGE 250 10M 100M FREQUENCY – Hz 1G 20 40 60 80 100 120 140 160 180 200 VALUE OF FEEDBACK RESISTOR ( RF) – 220 240 TPC 13. AD9631 Small Signal Frequency Response, G = +1 TPC 16. AD9631 Small Signal –3 dB Bandwidth vs. RF 0.1 0 –0.1 –0.2 VS = 5V RL = 100 G = +1 VO = 300mV p-p RF 150 RF 140 OUTPUT – dB 1 0 –1 –2 –3 –4 –5 –6 –7 –8 10M FREQUENCY – Hz 100M 500M –9 1M VS = 5V RL = 100 VO = 4V p-p RF 250 RF = 50 GAIN – dB –0.3 –0.4 –0.5 –0.6 –0.7 –0.8 –0.9 1M RF 100 RF 120 TO 250 BY 50 10M FREQUENCY – Hz 100M 500M TPC 14. AD9631 0.1 dB Flatness, N Package (for R Package Add 20 W to RF) TPC 17. AD9631 Large Signal Frequency Response, G = +1 90 80 70 PHASE 60 50 100 80 60 40 20 0 –20 GAIN –40 –60 –80 –100 –120 1G 1 0 PHASE MARGIN – Degrees –1 –2 VS = 5V RL = 100 VO = 300mV p-p RF 267 GAIN – dB 40 30 20 10 0 –10 –20 10k 100k 1M 10M FREQUENCY – Hz 100M GAIN – dB –3 –4 –5 –6 –7 –8 –9 1M 10M 100M FREQUENCY – Hz 1G TPC 15. AD9631 Open-Loop Gain and Phase Margin vs. Frequency, RL = 100 W TPC 18. AD9631 Small Signal Frequency Response, G = –1 –6– R EV. C AD9631/AD9632 –30 VS = 5V RL = 500 G = +1 VO = 2V p-p DIFF GAIN – % 0.10 0.05 0.00 –0.05 –0.10 1ST 2ND 3RD 4TH 5TH 6TH 7TH 8TH 9TH 10TH 11TH DIFF PHASE – Degrees HARMONIC DISTORTION – dBc –50 –70 –90 SECOND HARMONIC –110 THIRD HARMONIC 0.10 0.05 0.00 –0.05 –0.10 1ST 2ND 3RD 4TH 5TH 6TH 7TH 8TH 9TH 10TH 11TH –130 10k 100k 1M FREQUENCY – Hz 10M 100M TPC 19. AD9631 Harmonic Distortion vs. Frequency, RL = 500 W TPC 22. AD9631 Differential Gain and Phase Error, G = +2, RL = 150 W –30 VS = 5V RL = 100 G = +1 VO = 2V p-p 0.3 HARMONIC DISTORTION – dBc –50 0.2 0.1 SECOND HARMONIC –90 ERROR – % THIRD HARMONIC 10M 100M –70 0.0 –0.1 –110 –0.2 –130 10k –0.3 100k 1M FREQUENCY – Hz 0 10 20 30 40 50 SETTLING TIME – ns 60 70 80 TPC 20. AD9631 Harmonic Distortion vs. Frequency, RL = 100 W TPC 23. AD9631 Short-Term Settling Time, 2 V Step, RL = 100 W 60 55 0.3 0.2 50 INTERCEPT – dBm 40 35 30 ERROR – % 20 50 60 70 80 90 100 30 40 FREQUENCY – MHz 45 0.1 0.0 –0.1 25 20 10 –0.2 0 1 2 3 4 5 6 7 SETTLING TIME – s 8 9 10 TPC 21. AD9631 Third Order Intercept vs. Frequency TPC 24. AD9631 Long-Term Settling Time, 2 V Step, RL = 100 W R EV. C –7– AD9631/AD9632 7 6 5 4 GAIN – dB RF 325 VS = 5V RL = 100 VO = 300mV p-p RF 125 RF 425 RF 225 –3dB BANDWIDTH – MHz 350 VS = 5V RL = 100 GAIN = +2 N PACKAGE 300 3 2 1 0 –1 –2 –3 1M 10M 100M FREQUENCY – Hz 250 RIN 200 100 150 49.9 RF R PACKAGE AD9632 RL 1G 100 150 200 250 300 350 400 VALUE OF RF, RIN – 450 500 550 TPC 25. AD9632 Small Signal Frequency Response, G = +2 TPC 28. AD9632 Small Signal –3 dB Bandwidth vs. RF, RIN 0.1 0 –0.1 –0.2 OUTPUT – dB 7 6 RF 525 VS = 5V RL = 100 VO = 4V p-p OUTPUT – dB VS = 5V RL = 100 G = +2 VO = 300mV p-p RF 275 5 4 3 2 1 0 –1 –2 –3 1M RF 325 RF 375 RF 425 RF = 125 –0.3 –0.4 –0.5 –0.6 –0.7 –0.8 –0.9 1M TO 525 BY 100 10M FREQUENCY – Hz 100M 10M FREQUENCY – Hz 100M 500M TPC 26. AD9632 0.1 dB Flatness, N Package (for R Package Add 20 W to RF) TPC 29. AD9632 Large Signal Frequency Response, G = +2 65 60 55 50 45 40 35 30 25 20 15 10 5 0 –5 –10 –15 10k GAIN –100 –150 100 50 0 –50 PHASE – Degrees 1 0 –1 VS = 5V RL = 100 VO = 300mV p-p PHASE –2 GAIN – dB AOL – dB –3 –4 –5 –6 –7 RF, RIN 267 –200 –250 1G –8 –9 1M 100k 1M 10M FREQUENCY – Hz 100M 10M 100M FREQUENCY – Hz 1G TPC 27. AD9632 Open-Loop Gain and Phase Margin vs. Frequency, RL = 100 W TPC 30. AD9632 Small Signal Frequency Response, G = –1 –8– R EV. C AD9631/AD9632 –30 DIFF GAIN – % 0.04 VS = 5V RL = 500 G = +2 VO = 2V p-p 0.02 0.00 –0.02 –0.04 1ST 2ND 3RD 4TH 5TH 6TH 7TH 8TH 9TH 10TH 11TH HARMONIC DISTORTION – dBc –50 –70 DIFF PHASE – Degrees –90 SECOND HARMONIC THIRD HARMONIC 0.04 0.02 0.00 –0.02 –0.04 1ST 2ND 3RD 4TH 5TH 6TH 7TH 8TH 9TH 10TH 11TH –110 –130 10k 100k 1M FREQUENCY – Hz 10M 100M TPC 31. AD9632 Harmonic Distortion vs. Frequency, RL = 500 W TPC 34. AD9632 Differential Gain and Phase Error G = +2, RL = 150 W –30 VS = 5V RL = 100 G = +2 VO = 2V p-p SECOND HARMONIC 0.2 HARMONIC DISTORTION – dBc –50 0.1 ERROR – % THIRD HARMONIC –70 0.0 –90 –0.1 –110 –0.2 –130 10k –0.3 100k 1M FREQUENCY – Hz 10M 100M 0 10 20 30 40 50 SETTLING TIME – ns 60 70 80 TPC 32. AD9632 Harmonic Distortion vs. Frequency, RL = 100 W TPC 35. AD9632 Short-Term Settling Time, 2 V Step, RL = 100 W 50 45 0.3 0.2 40 INTERCEPT – dBm 30 25 20 ERROR – % 20 50 60 70 80 90 100 30 40 FREQUENCY – MHz 35 0.1 0.0 –0.1 15 10 10 –0.2 0 1 2 3 4 5 6 7 SETTLING TIME – s 8 9 10 TPC 33. AD9632 Third Order Intercept vs. Frequency TPC 36. AD9632 Long-Term Settling Time, 2 V Step, RL = 100 W R EV. C –9– AD9631/AD9632 24 21 INPUT NOISE VOLTAGE – nV/ Hz 17 VS = 5V INPUT NOISE VOLTAGE – nV/ Hz 15 VS = 5V 18 15 12 13 11 9 9 7 6 3 10 5 3 10 100 1k FREQUENCY – Hz 10k 100k 100 1k FREQUENCY – Hz 10k 100k TPC 37. AD9631 Noise vs. Frequency TPC 40. AD9632 Noise vs. Frequency 80 75 70 65 60 55 50 45 40 35 30 25 20 15 10 5 0 10k –PSRR +PSRR 80 75 70 65 60 55 50 45 40 35 30 25 20 15 10 5 0 10k –PSRR +PSRR PSRR – dB 100k 1M 10M FREQUENCY – Hz 100M 1G PSRR – dB 100k 1M 10M FREQUENCY – Hz 100M 1G TPC 38. AD9631 PSRR vs. Frequency TPC 41. AD9632 PSRR vs. Frequency 100 90 80 70 60 50 40 30 20 100k VS = 5V VCM = 1V RL = 100 100 90 80 70 60 50 40 30 20 100k VS = 5V VCM = 1V RL = 100 CMRR – dB 1M 10M FREQUENCY – Hz 100M 1G CMRR – dB 1M 10M FREQUENCY – Hz 100M 1G TPC 39. AD9631 CMRR vs. Frequency TPC 42. AD9632 CMRR vs. Frequency –10– R EV. C AD9631/AD9632 1000 VS = 5V GAIN = +1 100 1350 1250 1150 +AOL 1050 950 850 750 650 550 450 AD9631 +AOL –AOL –AOL AD9632 10 1 0.1 OPEN-LOOP GAIN – V/V 100k 1M FREQUENCY – Hz 10M 100M ROUT – 0.01 10k 350 –60 –40 –20 0 20 40 60 80 100 JUNCTION TEMPERATURE – C 120 140 TPC 43. AD9631 Output Resistance vs. Frequency TPC 46. Open-Loop Gain vs. Temperature 1000 VS = 5V GAIN = +1 100 76 74 72 70 –PSRR AD9632 PSRR – dB 10 68 66 +PSRR AD9632 –PSRR AD9631 ROUT – 1 64 62 0.1 60 +PSRR 58 AD9631 –40 –20 0 20 40 60 80 100 JUNCTION TEMPERATURE – C 120 140 0.01 10k 100k 1M FREQUENCY – Hz 10M 100M 56 –60 TPC 44. AD9632 Output Resistance vs. Frequency TPC 47. PSRR vs. Temperature 4.1 VS = 4.0 3.9 5V +VOUT –VOUT RL = 150 98 96 OUTPUT SWING – V 3.7 3.6 3.5 3.4 3.3 –60 +VOUT –VOUT RL = 50 CMRR – dB 3.8 94 92 90 88 +CMRR –CMRR –40 –20 20 40 60 80 100 0 JUNCTION TEMPERATURE – C 120 140 86 –60 –40 –20 20 40 60 80 100 0 JUNCTION TEMPERATURE – C 120 140 TPC 45. AD9631/AD9632 Output Swing vs. Temperature TPC 48. AD9631/AD9632 CMRR vs. Temperature R EV. C –11– AD9631/AD9632 21 6V 20 AD9631 240 250 AD9631 SHORT CIRCUIT CURRENT – mA SINK 230 220 AD9632 210 SOURCE SUPPLY CURRENT – mA 19 6V 18 5V 17 5V 16 15 AD9632 AD9631 AD9632 SINK 200 190 SOURCE 14 –60 –40 –20 20 40 60 80 100 0 JUNCTION TEMPERATURE – C 120 140 180 –60 –40 –20 20 40 60 80 100 0 JUNCTION TEMPERATURE – C 120 140 TPC 49. Supply Current vs. Temperature TPC 52. Short Circuit Current vs. Temperature –1.0 –1.5 INPUT OFFSET VOLTAGE – mV 2.0 1.5 INPUT BIAS CURRENT – A AD9632 –2.0 –2.5 –3.0 VS = –3.5 –4.0 –4.5 –5.0 –60 AD9631 VS = VS = –40 –20 0 20 40 60 80 100 JUNCTION TEMPERATURE – C 120 5V 6V 6V VS = 5V 1.0 0.5 0.0 –0.5 +IB –IB AD9631 AD9632 –IB –1.0 –1.5 –2.0 –60 +IB 140 –40 –20 0 20 40 60 80 100 JUNCTION TEMPERATURE – C 120 140 TPC 50. Input Offset Voltage vs. Temperature TPC 53. Input Bias Current vs. Temperature 220 200 180 160 140 3 WAFER LOTS COUNT = 1373 CUMULATIVE 100 90 80 70 180 160 140 120 3 WAFER LOTS COUNT = 573 CUMULATIVE 100 90 80 70 PERCENT COUNT 120 50 100 80 60 40 20 0 –7 –6 –5 –4 2 3 –3 –2 –1 0 1 INPUT OFFSET VOLTAGE – mV 4 5 6 7 FREQ. DIST 40 30 20 10 0 COUNT 100 50 80 40 60 FREQ. DIST 40 20 0 –7 30 20 10 0 –6 –5 –4 –3 –2 –1 0 1 2 3 INPUT OFFSET VOLTAGE – mV 4 5 6 7 TPC 51. AD9631 Input Offset Voltage Distribution TPC 54. AD9632 Input Offset Voltage Distribution –12– R EV. C PERCENT 60 60 AD9631/AD9632 THEORY OF OPERATION General The AD9631 and AD9632 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 AD9631 (gain of +1) and AD9632 (gain of +2). The AD9631/ AD9632 typically maintain 65 degrees of phase margin. This high margin minimizes the effects of signal and noise peaking. Feedback Resistor Choice When the AD9631 is used in the transimpedance (I to V) mode, such as in photodiode detection, the value of RF and diode capacitance (CI) are usually known. Generally, the value of RF selected will be in the kW 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 (