Low Power, Rail-to-Rail, Output Precision JFET Amplifier AD8643-EP Low supply current: 250 μA maximum Very low input bias current: 1 pA maximum Low offset voltage: 750 μV maximum Single-supply operation: 5 V to 26 V Dual-supply operation: ±2.5 V to ±13 V Rail-to-rail output Unity-gain stable No phase reversal PIN CONFIGURATION OUT A 1 14 OUT D –IN A 2 13 –IN D AD8643-EP 12 +IN D TOP VIEW (Not to Scale) 11 V– 10 +IN C –IN B 6 9 –IN C OUT B 7 8 OUT C +IN A 3 V+ 4 +IN B 5 09590-103 FEATURES Figure 1. 14-Lead SOIC (R-14) ENHANCED PRODUCT FEATURES Supports defense and aerospace applications (AQEC standard) Military temperature range (−55°C to +125°C) Controlled manufacturing baseline 1 assembly/test site 1 fabrication site Enhanced product change notification Qualification data available on request APPLICATIONS Line-/battery-powered instruments Photodiode amplifiers Precision current sensing Precision filters Portable audio GENERAL DESCRIPTION The AD8643-EP is a low power, precision JFET input amplifier featuring extremely low input bias current and rail-to-rail output. The ability to swing nearly rail-to-rail at the input and rail-to-rail at the output enables designers to buffer CMOS digital-to-analog converters (DACs), ASICs, and other wide output swing devices in single-supply systems. The outputs remain stable with capacitive loads of more than 500 pF. The AD8643-EP is suitable for applications using multichannel boards that require low power to manage heat. Other applications include photodiodes and battery management. The AD8643-EP is fully specified over the military temperature range of −55°C to +125°C. This device is available in a 14-lead SOIC. Additional applications information is available in the AD8643 data sheet. 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 ©2011 Analog Devices, Inc. All rights reserved. AD8643-EP TABLE OF CONTENTS Features .............................................................................................. 1 Electrical Characteristics..............................................................3 Enhanced Product Features ............................................................ 1 Absolute Maximum Ratings ............................................................5 Applications....................................................................................... 1 Thermal Resistance .......................................................................5 Pin Configuration............................................................................. 1 ESD Caution...................................................................................5 General Description ......................................................................... 1 Typical Performance Characteristics ..............................................6 Revision History ............................................................................... 2 Outline Dimensions ....................................................................... 12 Specifications..................................................................................... 3 Ordering Guide .......................................................................... 12 REVISION HISTORY 1/11—Revision 0: Initial Version Rev. 0 | Page 2 of 12 AD8643-EP SPECIFICATIONS ELECTRICAL CHARACTERISTICS VS = 5.0 V, VCM = 2.5 V, TA = 25°C, unless otherwise noted. Table 1. Parameter INPUT CHARACTERISTICS Offset Voltage Symbol Test Conditions/Comments Min VOS Typ Max Unit 50 1000 1.8 1.9 1 180 0.5 60 3 93 140 2.5 μV mV mV pA pA pA pA V dB V/mV μV/°C 0.01 ±6 V V V V mA −55°C < TA < +85°C +85°C < TA < +125°C, VCM = 1.5 V Input Bias Current IB 0.25 −55°C < TA < +125°C Input Offset Current IOS −55°C < TA < +125°C Input Voltage Range Common-Mode Rejection Ratio Large Signal Voltage Gain Offset Voltage Drift OUTPUT CHARACTERISTICS Output Voltage High CMRR AVO ΔVOS/ΔT VCM = 0 V to 2.5 V RL = 10 kΩ, VO = 0.5 to 4.5 V −55°C < TA < +125°C VOH IL = 1 mA, −55°C to +125°C Output Voltage Low 0 74 80 4.95 4.94 VOL IL = 1 mA, −55°C to +125°C Output Current POWER SUPPLY Power Supply Rejection Ratio Supply Current/Amplifier IOUT PSRR ISY VS = 5 V to 26 V 90 107 195 −55°C < TA < +125°C DYNAMIC PERFORMANCE Slew Rate Gain Bandwidth Product Phase Margin NOISE PERFORMANCE Voltage Noise Voltage Noise Density Current Noise Density SR GBP Øm eN p-p eN iN f = 0.1 Hz to 10 Hz f = 1 kHz f = 1 kHz Rev. 0 | Page 3 of 12 0.05 0.05 250 270 dB μA μA 2 2.5 50 V/μs MHz Degrees 4.0 28.5 0.5 μV p-p nV/√Hz fA/√Hz AD8643-EP VS= ±13 V, VCM = 0 V, TA = 25°C, unless otherwise noted. Table 2. Parameter INPUT CHARACTERISTICS Offset Voltage Symbol Test Conditions/Comments Min VOS Typ Max Unit 70 1000 1.8 1 260 0.5 65 +10 107 290 2.5 μV mV pA pA pA pA V dB V/mV μV/°C ±12 V V V V mA −55° < TA < +125°C Input Bias Current IB 0.25 –55°C < TA < +125°C Input Offset Current IOS −55°C < TA < +125°C Input Voltage Range Common-Mode Rejection Ratio Large Signal Voltage Gain Offset Voltage Drift OUTPUT CHARACTERISTICS Output Voltage High CMRR AVO ΔVOS/ΔT VCM = −13 V to +10 V RL = 10 kΩ, VO = –11 V to +11 V −55°C < TA < +125°C VOH IL = 1 mA, −55°C to +125°C Output Voltage Low −13 90 215 12.95 12.94 VOL −12.95 −12.94 IL = 1 mA, −55°C to +125°C Output Current POWER SUPPLY Power Supply Rejection Ratio Supply Current/Amplifier IOUT PSRR ISY VS = ±2.5 V to ±13 V 90 107 200 −55°C < TA < +125°C DYNAMIC PERFORMANCE Slew Rate Gain Bandwidth Product Phase Margin NOISE PERFORMANCE Voltage Noise Voltage Noise Density Current Noise Density SR GBP Øm eN p-p eN iN f = 0.1 Hz to 10 Hz f = 1 kHz f = 1 kHz Rev. 0 | Page 4 of 12 290 330 dB μA μA 3 3.5 60 V/μs MHz Degrees 4.2 27.5 0.5 μV p-p nV/√Hz fA/√Hz AD8643-EP ABSOLUTE MAXIMUM RATINGS Absolute maximum ratings apply at 25°C, unless otherwise noted. THERMAL RESISTANCE Table 3. θJA is specified for the worst-case conditions, that is, a device soldered in a circuit board for surface-mount packages. Parameter Supply Voltage Input Voltage Differential Input Voltage Output Short-Circuit Duration Storage Temperature Range Operating Temperature Range Junction Temperature Range Lead Temperature (Soldering, 60 sec) Rating 27.3 V V− to V+ ±Supply Voltage Indefinite −65°C to +150°C −55°C to +125°C −65°C to +150°C 300°C Table 4. Thermal Resistance Package Type 14-Lead SOIC (R) ESD CAUTION 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 12 θJA 120 θJC 36 Unit °C/W AD8643-EP TYPICAL PERFORMANCE CHARACTERISTICS 80 20 VSY = ±13V VSY = 5V VCM = 1.5V 18 70 16 NUMBER OF AMPLIFIERS FREQUENCY 60 50 40 30 20 14 12 10 8 6 09590-005 9.5 10.0 9.0 8.5 8.0 7.5 7.0 6.5 6.0 5.5 5.0 4.5 4.0 3.5 3.0 TCVOS (μV/°C) Figure 2. Input Offset Voltage Figure 5. Offset Voltage Drift 16 4.5 VSY = ±13V VSY = ±13V TA = 25°C 4.0 14 3.5 12 3.0 INPUT BIAS (pA) NUMBER OF AMPLIFIERS 2.5 2.0 1.5 09590-002 VOS (mV) 1.0 0 0 0 –0.60 –0.55 –0.50 –0.45 –0.40 –0.35 –0.30 –0.25 –0.20 –0.15 –0.10 –0.05 0 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 0.55 0.60 2 0.5 4 10 10 8 6 2.5 2.0 1.5 1.0 4 0.5 2 0 –9 –7 –5 –3 –1 1 3 5 7 9 11 13 15 09590-006 –15 –13 –11 150 09590-008 OFFSET VOLTAGE (μV/°C) –0.5 09590-003 9.5 10.0 9.0 8.5 8.0 7.5 7.0 6.5 6.0 5.5 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0 0.5 0 VCM (V) Figure 6. Input Bias Current vs. VCM Figure 3. Offset Voltage Drift 1000 70 VSY = ±13V VSY = ±2.5V INPUT BIAS CURRENT (pA) 60 40 30 20 100 10 1 10 0.1 VOS (mV) 09590-004 0 –0.60 –0.55 –0.50 –0.45 –0.40 –0.35 –0.30 –0.25 –0.20 –0.15 –0.10 –0.05 0 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 0.55 0.60 FREQUENCY 50 0 25 50 75 100 125 TEMPERATURE (°C) Figure 7. Input Bias Current vs. Temperature Figure 4. Input Offset Voltage Rev. 0 | Page 6 of 12 AD8643-EP 1.0 10M VSY = +5V OR ±5V 0.8 OPEN-LOOP GAIN (V/V) 0.6 INPUT BIAS (pA) 0.4 0.2 0 –0.2 –0.4 1M VSY = ±13V VSY = ±2.5V 100k –0.6 –1.0 –4 –3 –2 –1 0 1 2 3 4 5 VCM (V) 10k 0.1 09590-009 –5 1 Figure 8. Input Bias Current vs. VCM 1000 900 100 Figure 11. Open-Loop Gain vs. Load Resistance 1000 VSY = ±13V A 800 B C 700 100 D AVO (V/mV) 600 VOS (μV) 10 09590-012 –0.8 500 400 300 E 10 200 0 –15 –13 –11 –9 –7 –5 –3 –1 1 3 5 7 9 11 13 VCM (V) 15 09590-010 –100 1 –70 –50 –30 –10 10 30 50 70 90 110 130 150 TEMPERATURE (°C) Figure 9. Input Offset Voltage (VOS) vs. VCM 09590-013 A. VSY = ±13V, VO = ±11V, RL = 10kΩ B. VSY = ±13V, VO = ±11V, RL = 2kΩ C. VSY = +5V, VO = +0.5V/+4.5V, RL = 10kΩ D. VSY = +5V, VO = +0.5V/+4.5V, RL = 2kΩ E. VSY = +5V, VO = +0.5V/+4.5V, RL = 600Ω 100 Figure 12. Open-Loop Gain vs. Temperature 600 500 VSY = 5V 500 400 VSY = ±13V 400 300 300 200 100 100 0 0 –100 –100 –200 –200 –300 –300 –400 –400 0 0.5 1.0 1.5 2.0 VCM (V) 2.5 –600 –15 –10 –5 0 5 10 15 OUTPUT VOLTAGE (V) Figure 13. Input Error Voltage vs. Output Voltage for Resistive Loads Figure 10. Input Offset Voltage vs. VCM Rev. 0 | Page 7 of 12 09590-014 –500 –500 09590-011 VOS (μV) 200 AD8643-EP 10000 250 VSY = ±5V 200 VSY = 5V POS RAIL VSY – VOH RL = 2kΩ 0 RL = 10kΩ RL = 100kΩ –50 –100 –150 –200 RL = 100kΩ RL = 1kΩ RL = 10kΩ NEG RAIL RL = 2kΩ –300 –350 0 50 100 150 200 250 300 350 OUTPUT VOLTAGE FROM SUPPLY RAIL (mV) VOL 100 10 1 0.001 09590-015 –250 1000 0.01 0.1 1 10 100 LOAD CURRENT (mA) Figure 17. Output Saturation Voltage vs. Load Current Figure 14. Input Error Voltage vs. Output Voltage Within 300 mV of Supply Rails 800 70 VSY = ±13V RL = 2kΩ CL = 40pF 60 700 50 600 315 270 225 40 180 500 GAIN (dB) GAIN 400 +25°C 300 09590-018 RL = 1kΩ 50 30 135 20 PHASE 45 0 0 +125°C 200 –55°C 90 10 –10 –45 –20 –90 PHASE (Degrees) 100 SATURATION VOLTAGE (mV) INPUT VOLTAGE (μV) 150 100 8 12 16 20 24 28 VSY (V) –30 10k 09590-016 4 1M 10M FREQUENCY (Hz) Figure 15. Quiescent Current vs. Supply Voltage at Different Temperatures Figure 18. Open-Loop Gain and Phase Margin vs. Frequency 70 10000 VSY = ±13V 315 VSY = 5V RL = 2kΩ CL = 40pF 60 VSY – VOH 50 270 225 GAIN (dB) 40 100 –VSY – VOL 180 GAIN 30 135 20 90 PHASE 10 45 0 0 PHASE (Degrees) 1000 1 0.001 0.01 0.1 1 10 LOAD CURRENT (mA) 100 Figure 16. Output Saturation Voltage vs. Load Current –10 –45 –20 –90 –30 10k –135 100k 1M 10M FREQUENCY (Hz) Figure 19. Open-Loop Gain and Phase Margin vs. Frequency Rev. 0 | Page 8 of 12 09590-020 10 09590-017 SATURATION VOLTAGE (mV) –135 100k 09590-019 0 AD8643-EP 70 140 VSY = ±13V RL = 2kΩ CL = 40pF 60 50 120 VSY = 5V 100 40 80 30 CMRR (dB) 20 G = +10 10 0 60 40 20 –20 –20 –40 10k 100k 1M –60 1k 09590-021 10M FREQUENCY (Hz) 10k Figure 20. Closed-Loop Gain vs. Frequency 140 60 120 50 100 40 80 PSRR (dB) GAIN (dB) G = +100 30 20 G = +10 10 0 10M VSY = ±13V +PSRR 60 –PSRR 40 20 0 G = +1 –10 –20 –20 –40 100k 1M –60 1k 09590-022 10k 10M FREQUENCY (Hz) 10k 100k 1M 10M 10M FREQUENCY (Hz) Figure 24. PSRR vs. Frequency Figure 21. Closed-Loop Gain vs. Frequency 140 140 120 1M Figure 23. CMRR vs. Frequency 70 –30 1k 100k FREQUENCY (Hz) 09590-025 –30 1k 09590-024 0 G = +1 –10 09590-026 GAIN (dB) G = +100 VSY = ±13V 120 100 100 80 80 60 60 VSY = 5V PSRR (dB) 40 20 40 0 –20 –20 –40 –40 –60 1k 10k 100k 1M FREQUENCY (Hz) 10M –PSRR 20 0 09590-023 CMRR (dB) +PSRR –60 1k 10k 100k 1M FREQUENCY (Hz) Figure 25. PSRR vs. Frequency Figure 22. CMRR vs. Frequency Rev. 0 | Page 9 of 12 AD8643-EP 1000 15 VSY = ±13V VS = ±13V GAIN = +5 G = +100 10 TS + (1%) 10 G = +10 1 G = +1 0.1 5 TS + (0.1%) 0 –5 TS – (0.1%) –10 1k 10k 100k 1M 10M 100M FREQUENCY (Hz) –15 09590-027 0.01 TS – (1%) 0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 SETTLING TIME (μs) 09590-030 OUTPUT SWING (V) ZOUT (Ω) 100 Figure 29. Output Swing and Error vs. Settling Time Figure 26. Output Impedance vs. Frequency 70 1000 VS = ±13V RL = 10kΩ VIN = 100mV p-p AV = +1 VSY = 5V G = +100 60 100 OVERSHOOT (%) 10 G = +10 1 G = +1 40 OS– 30 OS+ 20 0.1 10 100k 1M 10M 100M FREQUENCY (Hz) 0 1 100 1000 1000 CAPACITANCE (pF) Figure 27. Output Impedance vs. Frequency T 10 09590-031 10k 09590-032 1k 09590-028 0.01 Figure 30. Small Signal Overshoot vs. Load Capacitance 70 VSY = ±13V VS = ±2.5V RL = 10kΩ VIN = 100mV p-p AV = +1 60 1 VIN OVERSHOOT (%) 50 40 OS– 30 OS+ 20 2 VOUT 10 CH1 10.0V CH2 10.0V M400μs A CH1 T 0.00000s 1.00V 09590-029 ZOUT (Ω) 50 0 1 10 100 CAPACITANCE (pF) Figure 31. Small Signal Overshoot vs. Load Capacitance Figure 28. No Phase Reversal Rev. 0 | Page 10 of 12 AD8643-EP 1k VS = ±13V G = +1M CH1 p-p = 4.26V VOLTAGE NOISE DENSITY (nV/ Hz) VSY = 5V M1.00s A CH1 –20.0V 10 1 10 100 1k 10k FREQUENCY (Hz) Figure 32. 0.1 Hz to 10 Hz Noise 09590-036 CH1 1.00V 09590-033 1 100 Figure 35. Voltage Noise Density 0.004 VS = ±2.5V G = +1M CH1 p-p = 4.06V VSY = ±13V LOAD = 100kΩ GAIN = +1 THD + NOISE (%) 0.001 1 8V p-p INPUT 1V p-p INPUT 2V p-p INPUT 0.0001 4V p-p INPUT M1.00s A CH1 –20.0V 0.000001 1 100 1k 10k 20k FREQUENCY (Hz) Figure 33. 0.1 Hz to 10 Hz Noise Figure 36. Total Harmonic Distortion + Noise vs. Frequency –40 VSY = ±13V 20kΩ –50 2kΩ – –60 – + –70 VIN 2kΩ 2kΩ + –80 100 (dB) –90 VIN = 18V p-p –100 –110 –120 10 VIN = 4.5V p-p –130 –140 –160 1 10 100 1k FREQUENCY (Hz) 10k 20 100 1k 10k FREQUENCY (Hz) Figure 37. Channel Separation Figure 34. Voltage Noise Density Rev. 0 | Page 11 of 12 100k 09590-041 VIN = 9V p-p –150 09590-035 VOLTAGE NOISE DENSITY (nV/ Hz) 1k 09590-037 CH1 1.00V 09590-034 0.00001 AD8643-EP OUTLINE DIMENSIONS 8.75 (0.3445) 8.55 (0.3366) 8 14 1 7 1.27 (0.0500) BSC 0.25 (0.0098) 0.10 (0.0039) COPLANARITY 0.10 0.51 (0.0201) 0.31 (0.0122) 6.20 (0.2441) 5.80 (0.2283) 0.50 (0.0197) 0.25 (0.0098) 1.75 (0.0689) 1.35 (0.0531) SEATING PLANE 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-AB 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. 060606-A 4.00 (0.1575) 3.80 (0.1496) Figure 38. 14-Lead Standard Small Outline Package [SOIC_N] Narrow Body (R-14) Dimensions shown in millimeters and (inches) ORDERING GUIDE Model 1 AD8643TRZ-EP AD8643TRZ-EP-R7 1 Temperature Range −55°C to +125°C −55°C to +125°C Package Description 14-lead SOIC_N 14-lead SOIC_N Z = RoHS Compliant Part. ©2011 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. D09590-0-1/11(0) Rev. 0 | Page 12 of 12 Package Option R-14 R-14