16 V, 1 MHz, CMOS Rail-to-Rail Input/Output Operational Amplifier ADA4665-2 PIN CONFIGURATIONS Lower power at high voltage: 290 μA per amplifier typical Low input bias current: 1 pA maximum Wide bandwidth: 1.2 MHz typical Slew rate: 1 V/μs typical Offset voltage drift: 3 μV/°C typical Single-supply operation: 5 V to 16 V Dual-supply operation: ±2.5 V to ±8 V Unity gain stable OUT A 1 –IN A 2 +IN A 3 ADA4665-2 TOP VIEW (Not to Scale) V– 4 8 V+ 7 OUT B 6 –IN B 5 +IN B 07650-001 FEATURES Figure 1. 8-Lead SOIC APPLICATIONS 8 V+ –IN A 2 ADA4665-2 7 OUT B +IN A 3 TOP VIEW (Not to Scale) 6 –IN B 5 +IN B V– 4 Portable systems High density power budget systems Medical equipment Physiological measurement Precision references Multipole filters Sensors Transimpedance amplifiers Buffer/level shifting 07650-002 OUT A 1 Figure 2. 8-Lead MSOP GENERAL DESCRIPTION The ADA4665-2 is a rail-to-rail input/output dual amplifier optimized for lower power budget designs. The ADA4665-2 offers a low supply current of 400 μA maximum per amplifier at 25°C and 600 μA maximum per amplifier over the extended industrial temperature range. This feature makes the ADA4665-2 well suited for low power applications. In addition, the ADA4665-2 has a very low bias current of 1 pA maximum, low offset voltage drift of 3 μV/°C, and bandwidth of 1.2 MHz. The combination of these features, together with a wide supply voltage range from 5 V to 16 V, allows the device to be used in a wide variety of other applications, including process control, instrumentation equipment, buffering, and sensor front ends. Furthermore, its rail-to-rail input and output swing adds to its versatility. The ADA4665-2 is specified from −40°C to +125°C and is available in standard SOIC and MSOP packages. Table 1. Low Cost Rail-to-Rail Input/Output Op Amps Supply Single Dual Quad 5V AD8541 AD8542 AD8544 16 V ADA4665-2 Table 2. Other Rail-to-Rail Input/Output Op Amps Supply Single Dual Quad 5V AD8603 AD8607 AD8609 16 V AD8663 AD8667 AD8669 36 V ADA4091-2 Rev. 0 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 ©2009 Analog Devices, Inc. All rights reserved. ADA4665-2 TABLE OF CONTENTS Features .............................................................................................. 1 Thermal Resistance .......................................................................5 Applications ....................................................................................... 1 ESD Caution...................................................................................5 Pin Configurations ........................................................................... 1 Typical Performance Characteristics ..............................................6 General Description ......................................................................... 1 Applications Information .............................................................. 15 Revision History ............................................................................... 2 Rail-to-Rail Input Operation .................................................... 15 Specifications..................................................................................... 3 Current Shunt Sensor ................................................................ 15 Electrical Characteristics—16 V Operation ............................. 3 Active Filters ............................................................................... 15 Electrical Characteristics—5 V Operation................................ 4 Outline Dimensions ....................................................................... 17 Absolute Maximum Ratings............................................................ 5 Ordering Guide .......................................................................... 17 REVISION HISTORY 1/09—Revision 0: Initial Version Rev. 0 | Page 2 of 20 ADA4665-2 SPECIFICATIONS ELECTRICAL CHARACTERISTICS—16 V OPERATION VSY = 16 V, VCM = VSY/2, TA = 25°C, unless otherwise noted. Table 3. Parameter INPUT CHARACTERISTICS Offset Voltage Symbol Test Conditions/Comments VOS Offset Voltage Drift Input Bias Current ∆VOS/∆T IB VCM = 16 V VCM = 0 V to 16 V −40°C ≤ TA ≤ +125°C −40°C ≤ TA ≤ +125°C Min Typ Max Unit 1 1 4 6 9 mV mV mV μV/°C pA pA pA pA V dB dB dB dB GΩ pF pF 3 0.1 −40°C ≤ TA ≤ +125°C Input Offset Current IOS Input Voltage Range Common-Mode Rejection Ratio CMRR Large Signal Voltage Gain AVO Input Resistance Input Capacitance, Differential Mode Input Capacitance, Common Mode OUTPUT CHARACTERISTICS Output Voltage High Output Voltage Low Short-Circuit Current Closed-Loop Output Impedance POWER SUPPLY Power Supply Rejection Ratio Supply Current per Amplifier DYNAMIC PERFORMANCE Slew Rate Settling Time to 0.1% Gain Bandwidth Product Phase Margin NOISE PERFORMANCE Voltage Noise Voltage Noise Density Current Noise Density 0.1 −40°C ≤ TA ≤ +125°C −40°C ≤ TA ≤ +125°C VCM = 0 V to 16 V −40°C ≤ TA ≤ +125°C RL = 10 kΩ, VO = 0.5 V to 15 V −40°C ≤ TA ≤ +125°C 0 55 50 85 75 RIN CINDM CINCM VOH VOL ISC ZOUT PSRR ISY 1 200 1 40 16 75 100 4 2 7 RL = 100 kΩ to VCM −40°C ≤ TA ≤ +125°C RL = 10 kΩ to VCM −40°C ≤ TA ≤ +125°C RL = 100 kΩ to VCM −40°C ≤ TA ≤ +125°C RL = 10 kΩ to VCM −40°C ≤ TA ≤ +125°C 15.95 15.9 15.9 15.8 15.95 4 40 7.5 15 75 150 ±30 100 f = 100 kHz, AV = 1 VSY = 5 V to 16 V −40°C ≤ TA ≤ +125°C IO = 0 mA −40°C ≤ TA ≤ +125°C 15.99 70 65 95 290 400 600 V V V V mV mV mV mV mA Ω dB dB μA μA SR tS GBP ΦM RL = 10 kΩ, CL = 50 pF, AV = 1 VIN = 1 V step, RL = 2 kΩ, CL = 50 pF RL = 10 kΩ, CL = 50 pF, AV = 1 RL = 10 kΩ, CL = 50 pF, AV = 1 1 6.5 1.2 50 V/μs μs MHz Degrees en p-p en f = 0.1 Hz to 10 Hz f = 1 kHz f = 10 kHz f = 1 kHz 3 32 27 50 μV p-p nV/√Hz nV/√Hz fA/√Hz in Rev. 0 | Page 3 of 20 ADA4665-2 ELECTRICAL CHARACTERISTICS—5 V OPERATION VSY = 5 V, VCM = VSY/2, TA = 25°C, unless otherwise noted. Table 4. Parameter INPUT CHARACTERISTICS Offset Voltage Symbol Test Conditions/Comments VOS Offset Voltage Drift Input Bias Current ∆VOS/∆T IB VCM = 5 V VCM = 0 V to 5 V −40°C ≤ TA ≤ +125°C −40°C ≤ TA ≤ +125°C Min Typ Max Unit 1 1 4 6 9 mV mV mV μV/°C pA pA pA pA V dB dB dB dB GΩ pF pF 3 0.1 −40°C ≤ TA ≤ +125°C Input Offset Current IOS Input Voltage Range Common-Mode Rejection Ratio CMRR Large Signal Voltage Gain AVO Input Resistance Input Capacitance, Differential Mode Input Capacitance, Common Mode OUTPUT CHARACTERISTICS Output Voltage High Output Voltage Low Short-Circuit Current Closed-Loop Output Impedance POWER SUPPLY Power Supply Rejection Ratio Supply Current per Amplifier DYNAMIC PERFORMANCE Slew Rate Settling Time to 0.1% Gain Bandwidth Product Phase Margin NOISE PERFORMANCE Voltage Noise Voltage Noise Density Current Noise Density 0.1 −40°C ≤ TA ≤ +125°C −40°C ≤ TA ≤ +125°C VCM = 0 V to 5 V −40°C ≤ TA ≤ +125°C RL = 10 kΩ, VO = 0.5 V to 4.5 V −40°C ≤ TA ≤ +125°C 0 55 50 85 75 RIN CINDM CINCM VOH VOL ISC ZOUT PSRR ISY 1 100 1 10 5 75 100 1 2 7 RL = 100 kΩ to VCM −40°C ≤ TA ≤ +125°C RL = 10 kΩ to VCM −40°C ≤ TA ≤ +125°C RL = 100 kΩ to VCM −40°C ≤ TA ≤ +125°C RL = 10 kΩ to VCM −40°C ≤ TA ≤ +125°C 4.95 4.9 4.9 4.8 4.96 3 30 5 10 50 100 ±8 100 f = 100 kHz, AV = 1 VSY = 5 V to 16 V −40°C ≤ TA ≤ +125°C IO = 0 mA −40°C ≤ TA ≤ +125°C 4.99 70 65 95 270 350 600 V V V V mV mV mV mV mA Ω dB dB μA μA SR tS GBP ΦM RL = 10 kΩ, CL = 50 pF, AV = 1 VIN = 1 V step, RL = 2 kΩ, CL = 50 pF RL = 10 kΩ, CL = 50 pF, AV = 1 RL = 10 kΩ, CL = 50 pF, AV = 1 1 6.5 1.2 50 V/μs μs MHz Degrees en p-p en f = 0.1 Hz to 10 Hz f = 1 kHz f = 10 kHz f = 1 kHz 3 32 27 50 μV p-p nV/√Hz nV/√Hz fA/√Hz in Rev. 0 | Page 4 of 20 ADA4665-2 ABSOLUTE MAXIMUM RATINGS THERMAL RESISTANCE Table 5. Parameter Supply Voltage Input Voltage1 Input Current Differential Input Voltage Output Short-Circuit Duration to GND Storage Temperature Range Operating Temperature Range Junction Temperature Range Lead Temperature (Soldering, 60 sec) 1 Rating 16.5 V GND − 0.3 V to VSY + 0.3 V ±10 mA ±VSY Indefinite −65°C to +150°C −40°C to +125°C −65°C to +150°C 300°C θJA is specified for the worst-case conditions, that is, a device soldered in a circuit board for surface-mount packages. This value was measured using a 4-layer JEDEC standard printed circuit board. Table 6. Thermal Resistance Package Type 8-Lead SOIC_N (R-8) 8-Lead MSOP (RM-8) ESD CAUTION The input pins have clamp diodes to the power supply pins. 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. Rev. 0 | Page 5 of 20 θJA 158 186 θJC 43 52 Unit °C/W °C/W ADA4665-2 TYPICAL PERFORMANCE CHARACTERISTICS TA = 25°C, unless otherwise noted. 70 70 VSY = 5V VCM = VSY/2 VSY = 16V VCM = VSY/2 60 NUMBER OF AMPLIFIERS 50 40 30 20 40 30 20 10 –5 –4 –3 –2 –1 0 1 VOS (mV) 2 3 4 5 6 0 –6 07650-006 0 –6 –5 Figure 3. Input Offset Voltage Distribution –1 0 1 VOS (mV) 2 3 4 5 6 VSY = 16V –40°C ≤ TA ≤ +125°C 9 8 7 6 5 4 3 7 6 5 4 3 2 2 1 1 0 1 2 3 4 5 6 TCVOS (µV/°C) 7 8 9 10 0 0 Figure 4. Input Offset Voltage Drift Distribution 2 3 4 5 6 TCVOS (µV/°C) 7 8 9 10 Figure 7. Input Offset Voltage Drift Distribution 5 5 VSY = 5V 4 2 2 VOS (mV) 3 1 0 1 0 –1 –1 –2 –2 –3 –3 1 2 3 4 VCM (V) 5 –4 07650-008 0 VSY = 16V 4 3 –4 1 07650-004 NUMBER OF AMPLIFIERS 8 07650-007 NUMBER OF AMPLIFIERS –2 10 VSY = 5V –40°C ≤ TA ≤ +125°C 9 VOS (mV) –3 Figure 6. Input Offset Voltage Distribution 10 0 –4 07650-003 10 50 Figure 5. Input Offset Voltage vs. Common-Mode Voltage 0 2 4 6 8 VCM (V) 10 12 14 Figure 8. Input Offset Voltage vs. Common-Mode Voltage Rev. 0 | Page 6 of 20 16 07650-005 NUMBER OF AMPLIFIERS 60 ADA4665-2 TA = 25°C, unless otherwise noted. 1k 100 1k VSY = 5V IB+ IB– 100 1 1 0.1 0.1 0.01 0.01 50 75 TEMPERATURE (°C) 100 125 0.001 25 50 Figure 9. Input Bias Current vs. Temperature 1k 75 TEMPERATURE (°C) 1k 100 VSY = 16V 100 125°C 10 105°C 125°C IB (pA) 85°C 0.1 1 85°C 0.1 25°C 0.01 0.01 0.001 0.001 1 2 3 4 5 VCM (V) 0.0001 07650-013 0 0 2 4 6 8 VCM (V) 10 12 14 16 Figure 13. Input Bias Current vs. Input Common-Mode Voltage 10k OUTPUT VOLTAGE (VOH) TO SUPPLY RAIL (mV) 10k VSY = 5V 1k 100 10 –40°C +25°C +85°C +125°C 1 0.1 0.001 0.01 0.1 1 LOAD CURRENT (mA) 10 100 07650-014 OUTPUT VOLTAGE (VOH) TO SUPPLY RAIL (mV) Figure 10. Input Bias Current vs. Input Common-Mode Voltage 25°C Figure 11. Output Voltage (VOH) to Supply Rail vs. Load Current VSY = 16V 1k 100 10 1 –40°C +25°C +85°C +125°C 0.1 0.01 0.001 0.01 0.1 1 LOAD CURRENT (mA) 10 100 Figure 14. Output Voltage (VOH) to Supply Rail vs. Load Current Rev. 0 | Page 7 of 20 07650-011 IB (pA) 105°C 1 0.0001 125 Figure 12. Input Bias Current vs. Temperature VSY = 5V 10 100 07650-010 0.001 25 07650-009 IB (pA) 10 07650-012 IB (pA) 10 VSY = 16V IB+ IB– ADA4665-2 1k 100 10 –40°C +25°C +85°C +125°C 1 0.1 0.001 0.01 0.1 1 LOAD CURRENT (mA) 10 10k 100 1k 100 10 0.1 0.001 0.1 1 LOAD CURRENT (mA) 15.99 RL = 100kΩ 100 RL = 100kΩ 15.98 4.97 4.96 4.95 RL = 10kΩ 4.94 VSY = 5V 4.93 15.97 15.96 15.95 15.94 15.93 15.91 0 25 50 TEMPERATURE (°C) 75 100 125 15.90 –50 07650-019 –25 RL = 10kΩ 15.92 Figure 16. Output Voltage (VOH) vs. Temperature VSY = 16V –25 0 25 50 TEMPERATURE (°C) 75 100 125 07650-016 OUTPUT VOLTAGE, VOH (V) 4.98 Figure 19. Output Voltage (VOH) vs. Temperature 60 60 VSY = 5V VSY = 16V 50 RL = 10kΩ 30 20 10 RL = 10kΩ 40 30 20 10 RL = 100kΩ RL = 100kΩ 0 25 50 TEMPERATURE (°C) 75 100 125 0 –50 07650-020 –25 Figure 17. Output Voltage (VOL) vs. Temperature –25 0 25 50 TEMPERATURE (°C) 75 100 Figure 20. Output Voltage (VOL) vs. Temperature Rev. 0 | Page 8 of 20 125 07650-017 OUTPUT VOLTAGE, VOL (mV) 50 40 0 –50 10 16.00 4.99 OUTPUT VOLTAGE, VOH (V) 0.01 Figure 18. Output Voltage (VOL) to Supply Rail vs. Load Current 5.00 OUTPUT VOLTAGE, VOL (mV) –40°C +25°C +85°C +125°C 1 Figure 15. Output Voltage (VOL) to Supply Rail vs. Load Current 4.92 –50 VSY = 16V 07650-015 VSY = 5V OUTPUT VOLTAGE (VOL) TO SUPPLY RAIL (mV) 10k 07650-018 OUTPUT VOLTAGE (VOL) TO SUPPLY RAIL (mV) TA = 25°C, unless otherwise noted. ADA4665-2 TA = 25°C, unless otherwise noted. 135 45 20 GAIN 0 0 OPEN-LOOP GAIN (dB) 90 PHASE (Degrees) PHASE –40 1k 10k 100k FREQUENCY (Hz) –90 10M 1M PHASE 40 20 45 GAIN 0 –40 1k 40 30 CLOSED-LOOP GAIN (dB) AV = 10 20 10 0 AV = 1 –10 –20 0 100M AV = 1 –20 –40 10M AV = 10 –10 –40 10k 100k 1M FREQUENCY (Hz) –50 100 Figure 22. Closed-Loop Gain vs. Frequency 1k VSY = 5V 100 10k 100k 1M FREQUENCY (Hz) 10M 100M VSY = 16V 100 AV = 100 ZOUT (Ω) 10 AV = 10 10 1 AV = 100 AV = 10 AV = 1 0.01 10 AV = 1 0.1 100 1k 10k 100k FREQUENCY (Hz) 1M 10M 0.01 10 Figure 23. Output Impedance vs. Frequency 100 1k 10k 100k FREQUENCY (Hz) 1M Figure 26. Output Impedance vs. Frequency Rev. 0 | Page 9 of 20 10M 07650-023 0.1 07650-026 ZOUT (Ω) 1k Figure 25. Closed-Loop Gain vs. Frequency 1k 1 VSY = 16V RL = 10kΩ AV = 100 10 –30 1k –90 10M 1M 20 –30 –50 100 100k FREQUENCY (Hz) 50 VSY = 5V RL = 10kΩ 07650-025 CLOSED-LOOP GAIN (dB) 30 10k Figure 24. Open-Loop Gain and Phase vs. Frequency 50 AV = 100 0 –45 Figure 21. Open-Loop Gain and Phase vs. Frequency 40 90 –20 –45 –20 135 07650-022 40 VSY = 16V RL = 10kΩ CL = 50pF 60 07650-024 OPEN-LOOP GAIN (dB) 60 180 80 PHASE (Degrees) VSY = 5V RL = 10kΩ CL = 50pF 07650-021 180 80 ADA4665-2 TA = 25°C, unless otherwise noted. 100 100 VSY = 16V 90 80 80 70 70 60 60 50 50 40 100 1k 10k FREQUENCY (Hz) 100k 1M 40 100 Figure 27. CMRR vs. Frequency 1k 10k FREQUENCY (Hz) 100k Figure 30. CMRR vs. Frequency 120 120 VSY = 16V 100 100 80 80 PSRR (dB) 60 40 40 20 PSRR+ PSRR– –20 100 1k PSRR+ PSRR– 0 10k 100k FREQUENCY (Hz) 1M 10M –20 100 07650-031 0 Figure 28. PSRR vs. Frequency 70 10M VSY = 16V VIN = 100mV p-p RL = 10kΩ 60 OVERSHOOT (%) OS+ 50 40 OS– 50 OS+ 40 20 10 10 1k 0 10 07650-032 100 CAPACITANCE (pF) OS– 30 20 0 10 1M 80 VSY = 5V VIN = 100mV p-p RL = 10kΩ 60 30 10k 100k FREQUENCY (Hz) Figure 31. PSRR vs. Frequency 80 70 1k 07650-028 20 60 100 CAPACITANCE (pF) Figure 32. Small Signal Overshoot vs. Load Capacitance Figure 29. Small Signal Overshoot vs. Load Capacitance Rev. 0 | Page 10 of 20 1k 07650-029 PSRR (dB) VSY = 5V OVERSHOOT (%) 1M 07650-027 CMRR (dB) 90 07650-030 CMRR (dB) VSY = 5V ADA4665-2 TA = 25°C, unless otherwise noted. VSY = 5V RL = 2kΩ CL = 10pF TIME (100µs/DIV) 07650-033 07650-036 VOLTAGE (5V/DIV) VOLTAGE (1V/DIV) VSY = 16V RL = 2kΩ CL = 10pF TIME (100µs/DIV) Figure 33. Large Signal Transient Response Figure 36. Large Signal Transient Response VSY = 5V RL = 2kΩ CL = 10pF TIME (100µs/DIV) TIME (100µs/DIV) VSY = ±2.5V 0 INPUT –50 –100 2 1 OUTPUT 0 –1 VSY = ±8V 0 INPUT –50 –100 10 5 OUTPUT 0 07650-038 3 50 Figure 35. Positive Overload Recovery –5 TIME (20µs/DIV) Figure 38. Positive Overload Recovery Rev. 0 | Page 11 of 20 OUTPUT VOLTAGE (V) 50 07650-035 INPUT VOLTAGE (mV) Figure 37. Small Signal Transient Response OUTPUT VOLTAGE (V) INPUT VOLTAGE (mV) Figure 34. Small Signal Transient Response TIME (20µs/DIV) 07650-034 07650-037 VOLTAGE (50mV/DIV) VOLTAGE (50mV/DIV) VSY = 16V RL = 2kΩ CL = 10pF ADA4665-2 INPUT VOLTAGE (mV) 150 VSY = ±2.5V 100 50 INPUT 0 150 VSY = ±8V 100 50 INPUT 0 –3 TIME (20µs/DIV) –5 –10 TIME (20µs/DIV) Figure 39. Negative Overload Recovery Figure 42. Negative Overload Recovery VSY = 16V RL = 2kΩ CL = 50pF OUTPUT +5mV 0 –5mV INPUT OUTPUT TIME (2µs/DIV) +5mV ERROR BAND 0 –5mV TIME (2µs/DIV) Figure 40. Negative Settling Time to 0.1% Figure 43. Negative Settling Time to 0.1% INPUT INPUT +5mV TIME (2µs/DIV) 07650-044 0 –5mV VSY = 16V RL = 2kΩ CL = 50pF OUTPUT ERROR BAND 0 –5mV TIME (2µs/DIV) Figure 41. Positive Settling Time to 0.1% Figure 44. Positive Settling Time to 0.1% Rev. 0 | Page 12 of 20 +5mV 07650-041 OUTPUT VOLTAGE (500mV/DIV) VSY = 5V RL = 2kΩ CL = 50pF ERROR BAND 07650-040 VOLTAGE (500mV/DIV) INPUT 07650-043 VOLTAGE (500mV/DIV) VSY = 5V RL = 2kΩ CL = 50pF ERROR BAND 0 OUTPUT VOLTAGE (V) –2 OUTPUT 07650-039 –1 07650-042 0 OUTPUT VOLTAGE (V) OUTPUT VOLTAGE (500mV/DIV) INPUT VOLTAGE (mV) TA = 25°C, unless otherwise noted. ADA4665-2 TA = 25°C, unless otherwise noted. 100 100 1k 10k 100k FREQUENCY (Hz) 10 100 07650-048 10 100 1k 10k 100k FREQUENCY (Hz) Figure 45. Voltage Noise Density vs. Frequency Figure 48. Voltage Noise Density vs. Frequency VSY = 5V TIME (2s/DIV) 07650-046 07650-049 INPUT VOLTAGE NOISE (1µV/DIV) INPUT VOLTAGE NOISE (1µV/DIV) VSY = 16V TIME (2s/DIV) Figure 46. 0.1 Hz to 10 Hz Noise Figure 49. 0.1 Hz to 10 Hz Noise 900 900 +125°C 700 +85°C 600 +25°C 500 –40°C 800 SUPPLY CURRENT (µA) 800 400 300 700 VSY = 16V 600 VSY = 5V 500 200 400 0 0 2 4 6 8 10 SUPPLY VOLTAGE (V) 12 14 16 300 –50 Figure 47. Supply Current vs. Supply Voltage –25 0 25 50 TEMPERATURE (°C) 75 100 Figure 50. Supply Current vs. Temperature Rev. 0 | Page 13 of 20 125 07650-050 100 07650-047 SUPPLY CURRENT (µA) 07650-045 VOLTAGE NOISE DENSITY (nV/ Hz) VSY = 16V VOLTAGE NOISE DENSITY (nV/ Hz) VSY = 5V ADA4665-2 TA = 25°C, unless otherwise noted. 0 1kΩ CHANNEL SEPARATION (dB) –20 –40 –60 –80 –100 –120 VIN = 1V p-p VIN = 4V p-p 1k 10k –40 –60 –80 –100 –120 100k VIN = 1V p-p VIN = 5V p-p VIN = 15V p-p –160 100 1k 10k Figure 53. Channel Separation vs. Frequency 1 VSY = 5V RL = 10kΩ AV = 1 THD + NOISE (%) 0.1 0.01 VSY = 16V RL = 10kΩ AV = 1 0.1 0.01 VIN = 1V p-p VIN = 5V p-p VIN = 15V p-p VIN = 1V p-p VIN = 4V p-p 100 1k FREQUENCY (Hz) 10k 100k 0.001 10 07650-054 0.001 10 100k FREQUENCY (Hz) Figure 51. Channel Separation vs. Frequency THD + NOISE (%) 1kΩ –140 FREQUENCY (Hz) 1 100kΩ 100 1k FREQUENCY (Hz) 10k Figure 54. THD + Noise vs. Frequency Figure 52. THD + Noise vs. Frequency Rev. 0 | Page 14 of 20 100k 07650-052 –140 –160 100 VSY = 16V RL = 10kΩ AV = –100 100kΩ 07650-053 CHANNEL SEPARATION (dB) VSY = 5V RL = 10kΩ –20 AV = –100 07650-051 0 ADA4665-2 APPLICATIONS INFORMATION I RAIL-TO-RAIL INPUT OPERATION 16V SUPPLY The ADA4665-2 is a unity-gain stable CMOS operational amplifier designed with rail-to-rail input/output swing capability to optimize performance. The rail-to-rail input feature is vital to maintain the wide dynamic input voltage range and to maximize signal swing to both supply rails. For example, the rail-to-rail input feature is extremely useful in buffer applications where the input voltage must cover both the supply rails. RS 0.1Ω I R2 1MΩ VOUT* RL R1 10kΩ 16V 1/2 ADA4665-2 The input stage has two input differential pairs, nMOS and pMOS. When the input common-mode voltage is at the low end of the input voltage range, the pMOS input differential pair is active and amplifies the input signal. As the input commonmode voltage is slowly increased, the pMOS differential pair gradually turns off while the nMOS input differential pair turns on. This transition is inherent to all rail-to-rail input amplifiers that use the dual differential pairs topology. For the ADA4665-2, this transition occurs approximately 1 V away from the positive rail and results in a change in offset voltage due to the different offset voltages of the differential pairs (see Figure 5 and Figure 8). R3 10kΩ 07650-055 R4 1MΩ *VOUT = AMPLIFIER GAIN × VOLTAGE ACROSS RS = 100 × RS × I = 10 × I Figure 55. Low-Side Current Sensing Circuit RS 0.1Ω I 16V SUPPLY RL I R4 1MΩ R3 10kΩ 16V VOUT* CURRENT SHUNT SENSOR 1/2 ADA4665-2 Figure 55 shows a low-side current sensing circuit, and Figure 56 shows a high-side current sensing circuit using the ADA4665-2. A typical shunt resistor of 0.1 Ω is used. In these circuits, the difference amplifier amplifies the voltage drop across the shunt resistor by a factor of 100. For true difference amplification, matching of the resistor ratio is very important, where R1/R2 = R3/R4. The rail-to-rail feature of the ADA4665-2 allows the output of the op amp to almost reach 16 V (the power supply of the op amp). This allows the current shunt sensor to sense up to approximately 1.6 A of current. R2 1MΩ R1 10kΩ *VOUT = AMPLIFIER GAIN × VOLTAGE ACROSS RS = 100 × RS × I = 10 × I 07650-056 Many applications require the sensing of signals near the positive or the negative rails. Current shunt sensors are one such application and are mostly used for feedback control systems. They are also used in a variety of other applications, including power metering, battery fuel gauging, and feedback controls in electrical power steering. In such applications, it is desirable to use a shunt with very low resistance to minimize the series voltage drop. This not only minimizes wasted power, but also allows the measurement of high currents while saving power. The ADA4665-2 provides a low cost solution for implementing current shunt sensors. Figure 56. High-Side Current Sensing Circuit ACTIVE FILTERS The ADA4665-2 is well suited for active filter designs. An active filter requires an op amp with a unity-gain bandwidth at least 100 times greater than the product of the corner frequency, fc, and the quality factor, Q. An example of an active filter is the Sallen-Key, one of the most widely used filter topologies. This topology gives the user the flexibility of implementing either a low-pass or a high-pass filter by simply interchanging the resistors and capacitors. To achieve the desired performance, 1% or better component tolerances are usually required. Figure 57 shows a two-pole low-pass filter. It is configured as a unity-gain filter with cutoff frequency at 10 kHz. Resistor and capacitor values are chosen to give a quality factor, Q, of 1/√2 for a Butterworth filter, which has maximally flat pass-band frequency response. Figure 58 shows the frequency response of the low-pass Sallen-Key filter. The response falls off at a rate of 40 dB per decade after the cutoff frequency of 10 kHz. Rev. 0 | Page 15 of 20 ADA4665-2 C1 1nF VIN Figure 59 shows a two-pole high-pass filter, with cutoff frequency at 10 kHz and quality factor, Q, of 1/√2. +VSY R2 22.5kΩ C1 0.5nF R1 22.5kΩ VIN 1/2 VOUT ADA4665-2 –VSY C2 0.5nF 07650-057 C2 0.5nF R2 45kΩ Figure 57. Two-Pole Low-Pass Filter fc = 1/2 VOUT ADA4665-2 –VSY When R1 = R2 and C1 = 2C2, the values of Q and the cutoff frequency are calculated as follows: Q= +VSY 07650-059 R1 22.5kΩ Figure 59. Two-Pole High-Pass Filter When R2 = 2R1 and C1 = C2, the values of Q and the cutoff frequency are calculated as follows: R1 R2 C1 C2 C2(R1 + R2) 1 2π R1 R2 C1 C2 Q= fc = 10 R1 R2 C1 C2 R1(C1 + C2) 1 2π R1 R2 C1 C2 0 10 0 –10 –20 –20 –30 –40 GAIN (dB) –30 –40 –50 –60 –70 –90 1k 10k FREQUENCY (Hz) 100k 1M –100 –110 Figure 58. Low-Pass Filter: Gain vs. Frequency –120 10 100 1k 10k FREQUENCY (Hz) 100k Figure 60. High-Pass Filter: Gain vs. Frequency Rev. 0 | Page 16 of 20 1M 07650-060 –60 100 –50 –80 07650-058 GAIN (dB) –10 ADA4665-2 OUTLINE DIMENSIONS 5.00 (0.1968) 4.80 (0.1890) 5 1 4 1.27 (0.0500) BSC 0.25 (0.0098) 0.10 (0.0040) 6.20 (0.2441) 5.80 (0.2284) 1.75 (0.0688) 1.35 (0.0532) 0.51 (0.0201) 0.31 (0.0122) COPLANARITY 0.10 SEATING PLANE 0.50 (0.0196) 0.25 (0.0099) 45° 8° 0° 0.25 (0.0098) 0.17 (0.0067) 1.27 (0.0500) 0.40 (0.0157) COMPLIANT TO JEDEC STANDARDS MS-012-A A 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. 012407-A 8 4.00 (0.1574) 3.80 (0.1497) Figure 61. 8-Lead Standard Small Outline Package [SOIC_N] Narrow Body (R-8) Dimensions shown in millimeters and (inches) 3.20 3.00 2.80 8 3.20 3.00 2.80 5 1 5.15 4.90 4.65 4 PIN 1 0.65 BSC 0.95 0.85 0.75 1.10 MAX 0.15 0.00 0.38 0.22 0.23 0.08 COPLANARITY 0.10 0.80 0.60 0.40 8° 0° SEATING PLANE COMPLIANT TO JEDEC STANDARDS MO-187-AA Figure 62. 8-Lead Mini Small Outline Package [MSOP] (RM-8) Dimensions shown in millimeters ORDERING GUIDE Model ADA4665-2ARZ 1 ADA4665-2ARZ-RL1 ADA4665-2ARZ-R71 ADA4665-2ARMZ1 ADA4665-2ARMZ-R71 ADA4665-2ARMZ-RL1 1 Temperature Range −40°C to +125°C −40°C to +125°C −40°C to +125°C −40°C to +125°C −40°C to +125°C −40°C to +125°C Package Description 8-Lead SOIC_N 8-Lead SOIC_N 8-Lead SOIC_N 8-Lead MSOP 8-Lead MSOP 8-Lead MSOP Z = RoHS Compliant Part. Rev. 0 | Page 17 of 20 Package Option R-8 R-8 R-8 RM-8 RM-8 RM-8 Branding A26 A26 A26 ADA4665-2 NOTES Rev. 0 | Page 18 of 20 ADA4665-2 NOTES Rev. 0 | Page 19 of 20 ADA4665-2 NOTES ©2009 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. D07650-0-1/09(0) Rev. 0 | Page 20 of 20