24 MHz Rail-to-Rail Dual Amplifier AD8646 Offset voltage: 2.5 mV maximum Single-supply operation: 2.7 V to 5.5 V Low noise: 8 nV/√Hz Wide bandwidth: 24 MHz Slew rate: 12 V/μs Short-circuit output current: 150 mA No phase reversal Low input bias current: 1 pA Low supply current: 2 mA maximum Unity gain stable PIN CONFIGURATION OUTA 1 –INA 2 AD8646 8 V+ 7 OUTB TOP VIEW 6 –INB (Not to Scale) V– 4 5 +INB +INA 3 06527-001 FEATURES Figure 1. APPLICATIONS Battery-powered instruments Multipole filters ADC front ends Sensors Barcode scanners ASIC input or output amplifiers Audio amplifiers Photodiode amplifiers Datapath/mux/switch control GENERAL DESCRIPTION The AD8646 is a dual, rail-to-rail, input and output, singlesupply amplifier featuring low offset voltage, wide signal bandwidth, low input voltage, and low current noise. The combination of 24 MHz bandwidth, low offset, low noise, and very low input bias current makes these amplifiers useful in a wide variety of applications. Filters, integrators, photodiode amplifiers, and high impedance sensors all benefit from the combination of performance features. AC applications benefit from the wide bandwidth and low distortion. This amplifier offers high output drive capability, which is excellent for audio line drivers and other low impedance applications. Applications include portable and low powered instrumentation, audio amplification for portable devices, portable phone headsets, barcode scanners, and multipole filters. The ability to swing rail to rail at both the input and output enables designers to buffer CMOS ADCs, DACs, ASICs, and other wide output swing devices in single-supply systems. 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 ©2007 Analog Devices, Inc. All rights reserved. AD8646 TABLE OF CONTENTS 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 8/07—Revision 0: Initial Version Rev. 0 | Page 2 of 12 AD8646 SPECIFICATIONS VDD = 5 V, VCM = VDD/2, TA = +25oC, unless otherwise noted. Table 1. Parameter INPUT CHARACTERISTICS Offset Voltage Symbol Conditions VOS Offset Voltage Drift Input Bias Current ΔVOS/ΔT IB VCM = 2.5 V −40°C < TA < +125°C −40°C < TA < +125°C Min Typ Max Unit 0.6 2.5 3.2 7.5 1 50 550 0.5 50 250 5 84 116 mV mV μV/°C pA pA pA pA pA pA V dB dB 4.99 V 4.92 V V mV mV mV mV mA Ω 1.8 0.3 −40°C < TA < +85°C −40°C < TA < +125°C Input Offset Current IOS 0.1 −40°C < TA < +85°C −40°C < TA < +125°C Input Voltage Range Common-Mode Rejection Ratio Large Signal Voltage Gain OUTPUT CHARACTERISTICS Output Voltage High Output Voltage Low Output Current Closed-Loop Output Impedance POWER SUPPLY Power Supply Rejection Ratio Supply Current per Amplifier VCM CMRR AVO VOH VOL IOUT ZOUT PSRR ISY VCM = 0 V to 5 V RL = 2 kΩ, VO = 0.5 V to 4.5 V 0 67 104 IOUT = 1 mA −40°C < TA < +125°C IOUT = 10 mA −40°C < TA < +125°C IOUT = 1 mA −40°C < TA < +125°C IOUT = 10 mA −40°C < TA < +125°C Short circuit At 1 MHz, AV = 1 4.98 4.90 4.85 4.70 VDD = 2.7 V to 5.0 V 63 8.4 78 ±120 5 80 1.5 −40°C < TA < +125°C DYNAMIC PERFORMANCE Slew Rate Gain Bandwidth Product Phase Margin NOISE PERFORMANCE Peak-to-Peak Noise Voltage Noise Density SR GBP Øm en p-p en Channel Separation CS Total Harmonic Distortion Plus Noise THD+N 20 40 145 200 1.9 2.25 dB mA mA RL = 2 kΩ 11 27 77 V/μs MHz Degrees 0.1 Hz to 10 Hz f = 1 kHz f = 10 kHz f = 10 kHz f = 100 kHz V p-p = 0.1 V, RL = 600 Ω, f = 25 kHz, TA = 25°C AV = +1 AV = −10 2.3 8 6 −129 −119 μV nV/√Hz nV/√Hz dB dB 0.010 0.021 % % Rev. 0 | Page 3 of 12 AD8646 VDD = 2.7 V, VCM = VDD/2, TA = +25oC, unless otherwise noted. Table 2. Parameter INPUT CHARACTERISTICS Offset Voltage Symbol Conditions VOS Offset Voltage Drift Input Bias Current ΔVOS/ΔT IB VCM = 1.35 V −40°C < TA < +125°C −40°C < TA < +125°C Min Typ Max Unit 0.6 2.5 3.2 7.0 1 50 550 0.5 50 250 2.7 mV mV μV/°C pA pA pA pA pA pA V dB dB 1.5 0.2 −40°C < TA < +85°C −40°C < TA < +125°C Input Offset Current IOS 0.1 −40°C < TA < +85°C −40°C < TA < +125°C Input Voltage Range Common-Mode Rejection Ratio Large Signal Voltage Gain OUTPUT CHARACTERISTICS Output Voltage High Output Voltage Low Output Current Closed-Loop Output Impedance POWER SUPPLY Power Supply Rejection Ratio Supply Current per Amplifier VCM CMRR AVO VOH VOL IOUT ZOUT PSRR ISY VCM = 0 V to 2.7 V RL = 2 kΩ, VO = 0.5 V to 2.2 V 0 62 95 IOUT = 1 mA −40°C < TA < +125°C IOUT = 1 mA −40°C < TA < +125°C Short circuit At 1 MHz, AV = 1 2.65 2.60 VDD = 2.7 V to 5.0 V 63 79 107 2.68 11 ±63 5 80 1.6 −40°C < TA < +125°C DYNAMIC PERFORMANCE Slew Rate Gain Bandwidth Product Phase Margin NOISE PERFORMANCE Peak-to-Peak Noise Voltage Noise Density Channel Separation SR RL = 2 kΩ RL = 10 kΩ GBP Øm en p-p en CS 0.1 Hz to 10 Hz f = 1 kHz f = 10 kHz f = 10 kHz f = 100 kHz Rev. 0 | Page 4 of 12 25 30 1.9 2.25 V V mV mV mA Ω dB mA mA 11 V/μs 26 53 MHz Degrees 2.3 8 6 −129 −121 μV nV/√Hz nV/√Hz dB dB AD8646 ABSOLUTE MAXIMUM RATINGS THERMAL RESISTANCE Table 3. Parameter Supply Voltage Input Voltage Differential Input Voltage Output Short Circuit to GND Storage Temperature Range Operating Temperature Range Lead Temperature (Soldering 60 sec) Junction Temperature Rating 6V GND to VDD ±3 V Indefinite −65°C to +150°C −40°C to +125°C 300°C 150°C θJA is specified for the worst-case conditions, that is, a device soldered in a circuit board for surface-mount packages. Table 4. Thermal Resistance Package Type 8-Lead SOIC 8-Lead MSOP 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. ESD CAUTION Rev. 0 | Page 5 of 12 θJA 121 210 θJC 43 45 Unit °C/W °C/W AD8646 TYPICAL PERFORMANCE CHARACTERISTICS 300 VSY = 5V VCM = 2.5V TA = 25°C 2244 AMPLIFIERS 180 160 NUMBER OF AMPLIFIERS 250 NUMBER OF AMPLIFIERS 200 VSY = 2.7V VCM = 1.35V TA = 25°C 2244 AMPLIFIERS 200 150 100 140 120 100 80 60 40 50 –1.0 –0.5 0 0.5 1.0 1.5 2.0 VOS (mV) 0 –2.0 06527-002 –1.5 35 0 0.5 1.0 1.5 2.0 VSY = 5V –40°C < TA < +125°C 30 NUMBER OF AMPLIFIERS 25 20 15 10 25 20 15 10 5 5 0 1 2 3 4 5 6 0 06527-003 0 7 TCVOS (µV/°C) 0 3 4 5 6 7 8 Figure 6. VOS Drift (TCVOS) Distribution 1000 VSY = 2.7V TA = 25°C 600 2 TCVOS (µV/°C) Figure 3. VOS Drift (TCVOS) Distribution 800 1 06527-006 NUMBER OF AMPLIFIERS –0.5 Figure 5. Input Offset Voltage Distribution VSY = 2.7V –40°C < TA < +125°C 30 –1.0 VOS (mV) Figure 2. Input Offset Voltage Distribution 35 –1.5 06527-005 20 0 –2.0 VSY = 5V TA = 25°C 800 600 400 400 VOS (µV) 0 –200 200 0 –200 –400 –400 –600 –600 –800 0 0.3 0.6 0.9 1.2 1.5 1.8 2.1 2.4 2.7 VCM (V) Figure 4. Input Offset Voltage vs. Input Common-Mode Voltage –1000 0 1 2 3 4 5 VCM (V) Figure 7. Input Offset Voltage vs. Input Common-Mode Voltage Rev. 0 | Page 6 of 12 06527-007 –800 06527-004 VOS (µV) 200 AD8646 10000 1000 VDD – VOH VOL 10 1 0.01 0.1 1 10 100 LOAD CURRENT (mA) 100 10 VDD – VOH 1 OUTPUT SATURATION VOLTAGE (mV) VDD – VOH 15 VOL 5 –25 –10 5 20 35 50 65 80 95 110 125 TEMPERATURE (°C) 1000 80 VOL = 10mA 60 40 20 VSY – VOH = 1mA VOL = 1mA –25 –10 5 20 35 50 65 80 95 110 125 Figure 12. Output Saturation Voltage vs. Temperature 300 VSY = 5V TA = 125°C 250 INPUT BIAS CURRENT (pA) 250 200 150 100 50 200 150 100 50 0.75 1.00 1.25 1.50 1.75 COMMON-MODE VOLTAGE (V) 2.00 06527-010 INPUT BIAS CURRENT (pA) 100 TEMPERATURE (°C) VSY = 2.7V TA = 125°C 0 0.50 10 VSY – VOH = 10mA 100 Figure 9. Output Saturation Voltage vs. Temperature 300 1 VSY = 5V 0 –40 06527-009 OUTPUT SATURATION VOLTAGE (mV) 120 20 0 –40 0.1 Figure 11. Output Saturation Voltage vs. Load Current VSY = 2.7V IL = 1mA 10 0.01 LOAD CURRENT (mA) Figure 8. Output Saturation Voltage vs. Load Current 25 VOL 0.1 0.001 Figure 10. Input Bias Current vs. Common-Mode Voltage 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 INPUT COMMON-MODE VOLTAGE (V) Figure 13. Input Bias Current vs. Common-Mode Voltage Rev. 0 | Page 7 of 12 4.5 06527-013 0.1 0.001 1000 06527-012 100 VSY = 5V TA = 25°C 06527-011 OUTPUT SATURATION VOLTAGE (mV) VSY = 2.7V TA = 25°C 06527-008 OUTPUT SATURATION VOLTAGE (mV) 10000 AD8646 20 45 0 0 180 135 40 90 20 45 0 0 –20 –45 –20 –45 –40 –90 –40 –90 1 10 100 1k 10k FREQUENCY (kHz) 1 10 AV = 1 0 –20 AV = 10 20 AV = 1 0 –20 –40 10k 100k 1M 10M 100M FREQUENCY (Hz) –60 1k 06527-015 –60 1k 100k 1M 10M 100M FREQUENCY (Hz) Figure 15. Closed-Loop Gain vs. Frequency 250 10k 06527-018 –40 VSY = 5V TA = 25°C AV = 100 40 AV = 10 20 10k 60 CLOSED-LOOP GAIN (dB) CLOSED-LOOP GAIN (dB) 40 1k Figure 17. Open-Loop Gain and Phase vs. Frequency VSY = 2.7V TA = 25°C AV = 100 100 FREQUENCY (kHz) Figure 14. Open-Loop Gain and Phase vs. Frequency 60 –135 100k –60 06527-014 –135 100k –60 PHASE (Degrees) 90 GAIN (dB) 40 VSY = 5V RL = 1kΩ CL = 10pF TA = 25°C 60 PHASE (Degrees) GAIN (dB) 60 80 06527-017 180 VSY = 2.7V RL = 1kΩ CL = 10pF 135 TA = 25°C 80 Figure 18. Closed-Loop Gain vs. Frequency 120 VSY = 2.7V TA = 25°C VSY = 5V TA = 25°C 100 200 AV = 1 80 ZOUT (Ω) 150 100 AV = 10 AV = 10 60 AV = 100 40 AV = 100 50 0 1 10 100 1k 10k FREQUENCY (kHz) 100k 1M Figure 16. ZOUT vs. Frequency 0 1 10 100 1k 10k FREQUENCY (kHz) Figure 19. ZOUT vs. Frequency Rev. 0 | Page 8 of 12 100k 1M 06527-019 20 06527-016 ZOUT (Ω) AV = 1 AD8646 100 VSY = 2.7V TA = 25°C 80 80 60 60 CMRR (dB) 40 20 VSY = 5V TA = 25°C 40 20 10k 100k 1M 10M 100M FREQUENCY (Hz) 0 1k 06527-020 0 1k 10k Figure 20. CMRR vs. Frequency 1M 10M 100M Figure 23. CMRR vs. Frequency 100 100 VSY = 2.7V 90 T = 25°C A VSY = 5V TA = 25°C –PSRR 80 80 70 +PSRR 60 50 40 PSRR (dB) PSRR (dB) 100k FREQUENCY (Hz) 06527-023 CMRR (dB) 100 –PSRR 30 60 +PSRR 40 20 10 20 0 10k 100k 1M 10M 100M FREQUENCY (Hz) 0 06527-021 –20 1k 1 10 Figure 21. PSRR vs. Frequency 60 100 1k 10k 100k FREQUENCY (kHz) 06527-024 –10 Figure 24. PSRR vs. Frequency 60 VSY = ±1.35V TA = 25°C 50 VSY = ±2.5V TA = 25°C 50 OVERSHOOT (%) 40 +OVERSHOOT 30 20 40 30 +OVERSHOOT 20 –OVERSHOOT 10 0 1 10 100 CLOAD (pF) 1000 Figure 22. Small Signal Overshoot vs. Load Capacitance 0 1 10 100 CLOAD (pF) Figure 25. Small Signal Overshoot vs. Load Capacitance Rev. 0 | Page 9 of 12 1000 06527-025 10 06527-022 OVERSHOOT (%) –OVERSHOOT AD8646 VSY = 2.7V, VCM = 1.35V, VIN = 100mV p-p, TA = 25°C, RL = 10kΩ, CL = 100pF 06527-029 06527-026 (50mV/DIV) (50mV/DIV) VSY = 5V, VCM = 2.5V, VIN = 100mV p-p, TA = 25°C, RL = 10kΩ, CL = 100pF (200ns/DIV) (200ns/DIV) Figure 26. 2.7 V Small Signal Transient Response Figure 29. 5 V Small Signal Transient Response VSY = 2.7V, VIN = 2V p-p, TA = 25°C, RL = 10kΩ, CL = 100pF 06527-030 06527-027 (2V/DIV) (2V/DIV) VSY = 5V, VIN = 4V p-p, TA = 25°C, RL = 10kΩ, CL = 100pF (200ns/DIV) (200ns/DIV) Figure 27. 2.7 V Large Signal Transient Response Figure 30. 5 V Large Signal Transient Response 0.08 0.07 0.06 THD + N (%) 0.05 0.04 0.03 0.04 0.03 0.02 0.01 0.01 0 10 100 1k 10k FREQUENCY (Hz) 100k VSY = ±2.5V RL = 600Ω AV = –10 TA = 25°C 0.05 0.02 06527-028 THD + N (%) VSY = ±2.5V RL = 600Ω 0.07 AV = 1 TA = 25°C 0.06 0 10 100 1k 10k FREQUENCY (Hz) Figure 31. THD + Noise vs. Frequency Figure 28. THD + Noise vs. Frequency Rev. 0 | Page 10 of 12 100k 06527-031 0.08 AD8646 20 18 VDD = 5V 16 INPUT BIAS CURRENT (pA) VOLTAGE NOISE DENSITY (nV/ Hz) 1000 VSY = 5V TA = 25°C 14 12 10 8 6 4 100 10 1 1k 10k 100k FREQUENCY (Hz) 0.1 25 06527-032 0 100 4000 105 125 TA = 25°C BOTH AMPS ISY, BOTH AMPLIFIERS (µA) 3500 3.5 3.0 2.5 2.0 1.5 1.0 3000 2500 2000 1500 1000 10k FREQUENCY (kHz) 0 0 0.5 1.5 2.0 2.5 0 CHANNEL SEPARATION (dB) –20 06527-034 0.00V 4.0 4.5 5.0 VSY = 5V RL = 2kΩ AV = –100 TA = 25°C –40 –60 –80 VIN = 2V p-p –100 A CH1 3.5 Figure 36. Supply Current vs. Supply Voltage 2.3µV p-p M4.00s 3.0 VSY (V) Figure 33. Maximum Output Swing vs. Frequency VSY = 2.7V TO 5V TA = 25°C 1.0 –120 1k VIN = 0.5V p-p 10k FREQUENCY (Hz) Figure 34. 0.1 Hz to 10 Hz Voltage Noise Figure 37. Channel Separation Rev. 0 | Page 11 of 12 100k 06527-037 1k 06527-033 0 100 06527-036 500 0.5 INPUT REFERRED NOISE (1µV/DIV) OUTPUT SWING (V p-p) 4.0 80 Figure 35. Input Bias Current vs. Temperature VSY = 5V VIN = 4.9V AV = 1 RL = 10kΩ TA = 25°C 4.5 65 TEMPERATURE (°C) Figure 32. Voltage Noise Density vs. Frequency 5.0 45 06527-035 2 AD8646 OUTLINE DIMENSIONS 5.00 (0.1968) 4.80 (0.1890) 8 4.00 (0.1574) 3.80 (0.1497) 5 1 6.20 (0.2441) 5.80 (0.2284) 4 1.27 (0.0500) BSC 0.25 (0.0098) 0.10 (0.0040) 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) 012407-A 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. Figure 38. 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 1 5 5.15 4.90 4.65 4 PIN 1 0.65 BSC 0.95 0.85 0.75 0.15 0.00 1.10 MAX 0.38 0.22 COPLANARITY 0.10 0.23 0.08 0.80 0.60 0.40 8° 0° SEATING PLANE COMPLIANT TO JEDEC STANDARDS MO-187-AA Figure 39. 8-Lead Mini Small Outline Package [MSOP] (RM-8) Dimensions shown in millimeters ORDERING GUIDE Model AD8646ARZ 1 AD8646ARZ-REEL1 AD8646ARZ-REEL71 AD8646ARMZ-R21 AD8646ARMZ-REEL1 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 Package Description 8-Lead SOIC_N 8-Lead SOIC_N 8-Lead SOIC_N 8-Lead MSOP 8-Lead MSOP Z = RoHS Compliant Part. ©2007 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. D06527-0-8/07(0) Rev. 0 | Page 12 of 12 Package Option R-8 R-8 R-8 RM-8 RM-8 Branding A1V A1V