AD8027_8028

Low Distortion, High Speed Rail-to-Rail Input/Output Amplifiers AD8027/AD8028 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. Specifications subject to change without notice. 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 owners. One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. Tel: 781.329.4700 www.analog.com Fax: 781.461.3113 © 2005 Analog Devices, Inc. All rights reserved. FEATURES High speed 190 MHz, –3 dB bandwidth (G = +1) 100 V/μs slew rate Low distortion 120 dBc @ 1 MHz SFDR 80 dBc @ 5 MHz SFDR Selectable input crossover threshold Low noise 4.3 nV/√Hz 1.6 pA/√Hz Low offset voltage: 900 μV max Low power: 6.5 mA/amplifier supply current Power-down mode No phase reversal: VIN > |VS| + 200 mV Wide supply range: 2.7 V to 12 V Small packaging: SOIC-8, SOT-23-6, MSOP-10 APPLICATIONS Filters ADC drivers Level shifting Buffering Professional video Low voltage instrumentation GENERAL DESCRIPTION The AD8027/AD80281 are high speed amplifiers with rail-to- rail input and output that operate on low supply voltages and are optimized for high performance and wide dynamic signal range. The AD8027/AD8028 have low noise (4.3 nV/√Hz, 1.6 pA/√Hz) and low distortion (120 dBc at 1 MHz). In appli- cations that use a fraction of, or the entire input dynamic range and require low distortion, the AD8027/AD8028 are ideal choices. Many rail-to-rail input amplifiers have an input stage that switches from one differential pair to another as the input signal crosses a threshold voltage, which causes distortion. The AD8027/AD8028 have a unique feature that allows the user to select the input crossover threshold voltage through the SELECT pin. This feature controls the voltage at which the complementary transistor input pairs switch. The AD8027/ AD8028 also have intrinsically low crossover distortion. CONNECTION DIAGRAMS AD8027 SOT-23-6 (RT) VOUT 1 –VS 2 +IN 3 5 6 +VS DISABLE/SELECT 4 –IN + – 03327-B-001 NC = NO CONNECT NC AD8027 SOIC-8 (R) 1 –IN 2 +IN 3 –VS 4 +VS VOUT NC 8 7 6 5 DISABLE/SELECT VOUTB –IN B +IN B 8 7 6 5 +VSVOUTA AD8028 SOIC-8 (R) 1 –IN A 2 +IN A 3 –VS 4 + – – + VOUTB 10 9 +VS DISABLE/SELECT B –IN B +IN B 8 7 6DISABLE/SELECT A VOUTA AD8028 MSOP-10 (RM) 1 –IN A 2 +IN A 3 –VS 4 5 + – + – Figure 1. Connection Diagrams (Top View) With their wide supply voltage range (2.7 V to 12 V) and wide bandwidth (190 MHz), the AD8027/AD8028 amplifiers are designed to work in a variety of applications where speed and performance are needed on low supply voltages. The high per- formance of the AD8027/AD8028 is achieved with a quiescent current of only 6.5 mA/amplifier typical. The AD8027/AD8028 have a shutdown mode that is controlled via the SELECT pin. The AD8027/AD8028 are available in SOIC-8, MSOP-10, and SOT-23-6 packages. They are rated to work over the industrial temperature range of –40°C to +125°C. OUTPUT VOLTAGE (V p-p) 0 1 2 3 4 5 6 7 8 9 1 –140 –120 –100 –80 –60 –40 –20 SF D R (d B ) 0 G = +1 FREQUENCY = 100kHz RL = 1kΩ VS = ±5V VS = +3V VS = +5V 03327-A-063 Figure 2. SFDR vs. Output Amplitude 1Protected by U.S. patent numbers 6,486,737B1; 6,518,842B1 AD8027/AD8028 Rev. C | Page 2 of 24 TABLE OF CONTENTS Specifications..................................................................................... 3 Absolute Maximum Ratings............................................................ 6 Maximum Power Dissipation ..................................................... 6 ESD Caution.................................................................................. 6 Typical Performance Characteristics ............................................. 8 Theory of Operation ...................................................................... 17 Input Stage................................................................................... 17 Crossover Selection .................................................................... 17 Output Stage................................................................................ 18 DC Errors .................................................................................... 18 Wideband Operation ..................................................................... 19 Circuit Considerations .............................................................. 19 Applications..................................................................................... 21 Using the SELECT Pin............................................................... 21 Driving a 16-Bit ADC................................................................ 21 Band-Pass Filter.......................................................................... 22 Design Tools and Technical Support ....................................... 22 Outline Dimensions ....................................................................... 23 Ordering Guide .......................................................................... 24 REVISION HISTORY 3/05—Rev. B to Rev. C Updated Format..................................................................Universal Change to Figure 1 ........................................................................... 1 10/03—Rev. A to Rev. B Changes to Figure 1...........................................................................1 8/03—Rev. 0 to Rev. A Addition of AD8028........................................................... Universal Changes to GENERAL DESCRIPTION.........................................1 Changes to Figures 1, 3, 4, 8, 13, 15, 17 ......................... 1, 6, 7, 8, 9 Changes to Figures 58, 60........................................................ 18, 20 Changes to SPECIFICATIONS........................................................3 Updated OUTLINE DIMENSIONS .............................................22 Updated ORDERING GUIDE.......................................................23 3/03—Revision 0: Initial Version AD8027/AD8028 Rev. C | Page 3 of 24 SPECIFICATIONS VS = ±5 V at TA = 25°C, RL = 1 kΩ to midsupply, G = 1, unless otherwise noted. Table 1. Parameter Conditions Min Typ Max Unit DYNAMIC PERFORMANCE –3 dB Bandwidth G = 1, VO = 0.2 V p-p 138 190 MHz G = 1, VO = 2 V p-p 20 32 MHz Bandwidth for 0.1 dB Flatness G = 2, VO = 0.2 V p-p 16 MHz Slew Rate G = +1, VO = 2 V step/G = −1, VO = 2 V step 90/100 V/μs Settling Time to 0.1% G = 2, VO = 2 V step 35 ns NOISE/DISTORTION PERFORMANCE Spurious-Free Dynamic Range (SFDR) fC = 1 MHz, VO = 2 V p-p, RF = 24.9 Ω 120 dBc fC = 5 MHz, VO = 2 V p-p, RF = 24.9 Ω 80 dBc Input Voltage Noise f = 100 kHz 4.3 nV/√Hz Input Current Noise f = 100 kHz 1.6 pA/√Hz Differential Gain Error NTSC, G = 2, RL = 150 Ω 0.1 % Differential Phase Error NTSC, G = 2, RL = 150 Ω 0.2 Degrees Crosstalk, Output to Output G = 1, RL = 100 Ω, VOUT = 2 V p-p, VS = ±5 V @ 1 MHz −93 dB DC PERFORMANCE Input Offset Voltage SELECT = three-state or open, PNP active 200 800 μV SELECT = high NPN active 240 900 μV Input Offset Voltage Drift TMIN to TMAX 1.50 μV/°C Input Bias Current1 VCM = 0 V, NPN active 4 6 μA TMIN to TMAX 4 μA VCM = 0 V, PNP active −8 −11 μA TMIN to TMAX −8 μA Input Offset Current ±0.1 ±0.9 μA Open-Loop Gain VO = ±2.5 V 100 110 dB INPUT CHARACTERISTICS Input Impedance 6 MΩ Input Capacitance 2 pF Input Common-Mode Voltage Range −5.2 to +5.2 V Common-Mode Rejection Ratio VCM = ±2.5 V 90 110 dB SELECT PIN Crossover Low, Selection Input Voltage Three-state < ±20 μA −3.3 to +5 V Crossover High, Selection Input Voltage −3.9 to −3.3 V Disable Input Voltage −5 to −3.9 V Disable Switching Speed 50% of input to <10% of final VO 980 ns Enable Switching Speed 45 ns OUTPUT CHARACTERISTICS Output Overdrive Recovery Time (Rising/Falling Edge) VI = +6 V to −6 V, G = −1 40/45 ns Output Voltage Swing −VS + 0.10 +VS − 0.06, −VS + 0.06 +VS − 0.10 V Short-Circuit Output Sinking and Sourcing 120 mA Off Isolation VIN = 0.2 V p-p, f = 1 MHz, SELECT = low −49 dB Capacitive Load Drive 30% overshoot 20 pF POWER SUPPLY Operating Range 2.7 12 V Quiescent Current/Amplifier 6.5 8.5 mA Quiescent Current (Disabled) SELECT = low 370 500 μA Power Supply Rejection Ratio VS ± 1 V 90 110 dB 1 No sign or a plus sign indicates current into the pin; a minus sign indicates current out of the pin. AD8027/AD8028 Rev. C | Page 4 of 24 VS = 5 V at TA = 25°C, RL = 1 kΩ to midsupply, unless otherwise noted. Table 2. Parameter Conditions Min Typ Max Unit DYNAMIC PERFORMANCE −3 dB Bandwidth G = 1, VO = 0.2 V p-p 131 185 MHz G = 1, VO = 2 V p-p 18 28 MHz Bandwidth for 0.1 dB Flatness G = 2, VO = 0.2 V p-p 12 MHz Slew Rate G = +1, VO = 2 V step/G = −1, VO = 2 V step 85/100 V/μs Settling Time to 0.1% G = 2, VO = 2 V step 40 ns NOISE/DISTORTION PERFORMANCE Spurious-Free Dynamic Range (SFDR) fC = 1 MHz, VO = 2 V p-p, RF = 24.9 Ω 90 dBc fC = 5 MHz, VO = 2 V p-p, RF = 24.9 Ω 64 dBc Input Voltage Noise f = 100 kHz 4.3 nV/√Hz Input Current Noise f = 100 kHz 1.6 pA/√Hz Differential Gain Error NTSC, G = 2, RL = 150 Ω 0.1 % Differential Phase Error NTSC, G = 2, RL = 150 Ω 0.2 Degrees Crosstalk, Output to Output G = 1, RL = 100 Ω, VOUT = 2 V p-p, VS = ±5 V @ 1 MHz −92 dB DC PERFORMANCE Input Offset Voltage SELECT = three-state or open, PNP active 200 800 μV SELECT = high NPN active 240 900 μV Input Offset Voltage Drift TMIN to TMAX 2 μV/°C Input Bias Current1 VCM = 2.5 V, NPN active 4 6 μA TMIN to TMAX 4 μA VCM = 2.5 V, PNP active −8 −11 μA TMIN to TMAX −8 μA Input Offset Current ±0.1 ±0.9 μA Open-Loop Gain VO = 1 V to 4 V 96 105 dB INPUT CHARACTERISTICS Input Impedance 6 MΩ Input Capacitance 2 pF Input Common-Mode Voltage Range −0.2 to +5.2 V Common-Mode Rejection Ratio VCM = 0 V to 2.5 V 90 105 dB SELECT PIN Crossover Low, Selection Input Voltage Three-state < ±20 μA 1.7 to 5 V Crossover High, Selection Input Voltage 1.1 to 1.7 V Disable Input Voltage 0 to 1.1 V Disable Switching Speed 50% of input to <10% of final VO 1100 ns Enable Switching Speed 50 ns OUTPUT CHARACTERISTICS Overdrive Recovery Time (Rising/Falling Edge) VI = −1 V to +6 V, G = −1 50/50 ns Output Voltage Swing RL = 1 kΩ −VS + 0.08 +VS − 0.04, −VS + 0.04 +VS − 0.08 V Off Isolation VIN = 0.2 V p-p, f = 1 MHz, SELECT = low −49 dB Short-Circuit Current Sinking and sourcing 105 mA Capacitive Load Drive 30% overshoot 20 pF POWER SUPPLY Operating Range 2.7 12 V Quiescent Current/Amplifier 6 8.5 mA Quiescent Current (Disabled) SELECT = low 320 450 μA Power Supply Rejection Ratio VS ± 1 V 90 105 dB 1 No sign or a plus sign indicates current into the pin; a minus sign indicates current out of the pin. AD8027/AD8028 Rev. C | Page 5 of 24 VS = 3 V at TA = 25°C, RL = 1 kΩ to midsupply, unless otherwise noted. Table 3. Parameter Conditions Min Typ Max Unit DYNAMIC PERFORMANCE –3 dB Bandwidth G = 1, VO = 0.2 V p-p 125 180 MHz G = 1, VO = 2 V p-p 19 29 MHz Bandwidth for 0.1 dB Flatness G = 2, VO = 0.2 V p-p 10 MHz Slew Rate G = +1, VO = 2 V step/G = –1, VO = 2 V step 73/100 V/μs Settling Time to 0.1% G = 2, VO = 2 V step 48 ns NOISE/DISTORTION PERFORMANCE Spurious-Free Dynamic Range (SFDR) fC = 1 MHz, VO = 2 V p-p, RF = 24.9 Ω 85 dBc fC = 5 MHz, VO = 2 V p-p, RF = 24.9 Ω 64 dBc Input Voltage Noise f = 100 kHz 4.3 nV/√Hz Input Current Noise f = 100 kHz 1.6 pA/√Hz Differential Gain Error NTSC, G = 2, RL = 150 Ω 0.15 % Differential Phase Error NTSC, G = 2, RL = 150 Ω 0.20 Degrees Crosstalk, Output to Output G = 1, RL = 100 Ω, VOUT = 2 V p-p, VS = 3 V @ 1 MHz –89 dB DC PERFORMANCE Input Offset Voltage SELECT = three-state or open, PNP active 200 800 μV SELECT = high NPN active 240 900 μV Input Offset Voltage Drift TMIN to TMAX 2 μV/°C Input Bias Current1 VCM = 1.5 V, NPN active 4 6 μA TMIN to TMAX 4 μA VCM = 1.5 V, PNP active –8 –11 μA TMIN to TMAX –8 μA Input Offset Current ±0.1 ±0.9 μA Open-Loop Gain VO = 1 V to 2 V 90 100 dB INPUT CHARACTERISTICS Input Impedance 6 MΩ Input Capacitance 2 pF Input Common-Mode Voltage Range RL = 1 kΩ –0.2 to +3.2 V Common-Mode Rejection Ratio VCM = 0 V to 1.5 V 88 100 dB SELECT PIN Crossover Low, Selection Input Voltage Three-state < ±20 μA 1.7 to 3 V Crossover High, Selection Input Voltage 1.1 to 1.7 V Disable Input Voltage 0 to 1.1 V Disable Switching Speed 50% of input to <10% of final VO 1150 ns Enable Switching Speed 50 ns OUTPUT CHARACTERISTICS Output Overdrive Recovery Time (Rising/Falling Edge) VI = –1 V to +4 V, G = –1 55/55 ns Output Voltage Swing RL = 1 kΩ –VS + 0.07 +VS – 0.03, –VS + 0.03 +VS – 0.07 V Short-Circuit Current Sinking and sourcing 72 mA Off Isolation VIN = 0.2 V p-p, f = 1 MHz, SELECT = low –49 dB Capacitive Load Drive 30% Overshoot 20 pF POWER SUPPLY Operating Range 2.7 12 V Quiescent Current/Amplifier 6.0 8.0 mA Quiescent Current (Disabled) SELECT = low 300 420 μA Power Supply Rejection Ratio VS ± 1 V 88 100 dB 1 No sign or a plus sign indicates current into the pin; a minus sign indicates current out of the pin. AD8027/AD8028 Rev. C | Page 6 of 24 ABSOLUTE MAXIMUM RATINGS Table 4. Parameter Rating Supply Voltage 12.6 V Power Dissipation See Figure 3 Common-Mode Input Voltage ±VS ± 0.5 V Differential Input Voltage ±1.8 V Storage Temperature –65°C to +125°C Operating Temperature Range –40°C to +125°C Lead Temperature Range (Soldering 10 sec) 300°C Junction Temperature 150°C 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. MAXIMUM POWER DISSIPATION The maximum safe power dissipation in the AD8027/AD8028 package is limited by the associated rise in junction temperature (TJ) on the die. The plastic encapsulating the die locally reaches the junction temperature. At approximately 150°C, which is the glass transition temperature, the plastic changes its properties. Even temporarily exceeding this temperature limit may change the stresses that the package exerts on the die, permanently shifting the parametric performance of the AD8027/AD8028. Exceeding a junction temperature of 175°C for an extended period of time can result in changes in the silicon devices, potentially causing failure. The still-air thermal properties of the package and PCB (θJA), ambient temperature (TA), and the total power dissipated in the package (PD) determine the junction temperature of the die. The junction temperature can be calculated as ( )JADAJ θPTT ×+= The power dissipated in the package (PD) is the sum of the quiescent power dissipation and the power dissipated in the package due to the load drive for all outputs. The quiescent power is the voltage between the supply pins (VS) times the quiescent current (IS). Assuming the load (RL) is referenced to midsupply, then the total drive power is VS/2 × IOUT, some of which is dissipated in the package and some in the load (VOUT × IOUT). The difference between the total drive power and the load power is the drive power dissipated in the package. PD = Quiescent Power + (Total Drive Power − Load Power) ( ) L OUT L OUTS SSD R V R VV IVP 2 – 2 ⎟⎟⎠ ⎞ ⎜⎜⎝ ⎛ ×+×= RMS output voltages should be considered. If RL is referenced to VS−, as in single-supply operation, then the total drive power is VS × IOUT. If the rms signal levels are indeterminate, then consider the worst case, when VOUT = VS/4 for RL to midsupply. ( ) ( ) L S SSD R V IVP 24/+×= In single-supply operation with RL referenced to VS–, worst case is VOUT = VS/2. Airflow increases heat dissipation, effectively reducing θJA. Also, more metal directly in contact with the package leads from metal traces, through holes, ground, and power planes reduces the θJA. Care must be taken to minimize parasitic capacitances at the input leads of high speed op amps, as discussed in the PCB Layout section. ESD 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 this product 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 degrada- tion or loss of functionality. AD8027/AD8028 Rev. C | Page 7 of 24 Figure 3 shows the maximum safe power dissipation in the package vs. the ambient temperature for the SOIC-8 (125°C/W), SOT-23-6 (170°C/W), and MSOP-10 (130°C/W) packages on a JEDEC standard 4-layer board. Output Short Circuit Shorting the output to ground or drawing excessive current from the AD8027/AD8028 can likely cause catastrophic failure. AMBIENT TEMPERATURE (°C) M A XI M U M P O W ER D IS SI PA TI O N (W ) –55 –35 –15 5 25 45 65 85 105 125 0 0.5 1.0 1.5 2.0 SOT-23-6 SOIC-8 MSOP-10 03327-A-002 Figure 3. Maximum Power Dissipation vs. Ambient Temperature AD8027/AD8028 Rev. C | Page 8 of 24 TYPICAL PERFORMANCE CHARACTERISTICS Default conditions: VS = 5 V at TA = 25°C, RL = 1 kΩ, unless otherwise noted. FREQUENCY (MHz) 0.1 1 10 100 1000 –10 –9 –8 –7 –6 –5 –4 –3 –2 –1 0 1 2 N O R M A LI ZE D C LO SE D -L O O P G A IN (d B ) VOUT = 200mV p-p 03327-A-003 AD8027 G = +1 AD8028 G = +1 G = +10 G = –1 G = +2 Figure 4. Small Signal Frequency Response for Various Gains FREQUENCY (MHz) 0.1 1 10 100 1000 –10 –9 –8 –7 –6 –5 –4 –3 –2 –1 0 1 2 C LO SE D - L O O P G A IN (d B ) G = +1 VOUT = 200mV p-p VS = +5V VS = ±5V VS = +3VVS = +3V RF = 24.9Ω 03327-A-004 Figure 5. AD8027 Small Signal Frequency Response for Various Supplies 100 FREQUENCY (MHz) 0.1 1 10 1000 –10 –9 –8 –7 –6 –5 –4 –3 –2 –1 0 1 2 C LO SE D -L O O P G A IN (d B ) G = +1 VOUT = 2V p-p VS = +5V VS = ±5V VS = +3V 03327-A-005 Figure 6. Large Signal Frequency Response for Various Supplies FREQUENCY (MHz) 0.1 1 10 100 1000 –4 –3 –2 –1 0 1 2 3 4 5 6 7 8 C LO SE D -L O O P G A IN (d B ) G = +2 VOUT = 200mV p-p VS = +5V VS = ±5V VS = +3V 03327-A-006 Figure 7. Small Signal Frequency Response for Various Supplies FREQUENCY (MHz) 0.1 1 10 100 1000 –10 –9 –8 –7 –6 –5 –4 –3 –2 –1 0 1 2 C LO SE D -L O O P G A IN (d B ) G = +1 VOUT = 200mV p-p 03327-A-007 VS = ±5V VS = +5V VS = +3V Figure 8. AD8028 Small Signal Frequency Response for