a Single-Supply, Rail-to-Rail Low Power FET-Input Op Amp AD822 FEATURES True Single-Supply Operation Output Swings Rail-to-Rail Input Voltage Range Extends Below Ground Single-Supply Capability from 3 V to 36 V Dual-Supply Capability from 1.5 V to 18 V High Load Drive Capacitive Load Drive of 350 pF, G = +1 Minimum Output Current of 15 mA Excellent AC Performance for Low Power 800 A Max Quiescent Current per Amplifier Unity Gain Bandwidth: 1.8 MHz Slew Rate of 3.0 V/ms Good DC Performance 800 V Max Input Offset Voltage 2 V/C Typ Offset Voltage Drift 25 pA Max Input Bias Current Low Noise 13 nV/÷Hz @ 10 kHz No Phase Inversion CONNECTION DIAGRAM 8-Lead Plastic DIP, MSOP, and SOIC 8 V+ OUT1 1 –IN1 2 7 OUT2 +IN1 3 6 –IN2 V– 4 AD822 5 +IN2 with an input voltage range extending below the negative rail, allowing the AD822 to accommodate input signals below ground in the Single-Supply Mode. Output voltage swing extends to within 10 mV of each rail providing the maximum output dynamic range. Offset voltage of 800 mV max, offset voltage drift of 2 mV/∞C, input bias currents below 25 pA, and low input voltage noise provide dc precision with source impedances up to a Gigaohm. 1.8 MHz unity gain bandwidth, –93 dB THD at 10 kHz, and 3 V/ms slew rate are provided with a low supply current of 800 mA per amplifier. The AD822 drives up to 350 pF of direct capacitive load as a follower and provides a minimum output current of 15 mA. This allows the amplifier to handle a wide range of load conditions. Its combination of ac and dc performance, plus the outstanding load drive capability, results in an exceptionally versatile amplifier for the single-supply user. APPLICATIONS Battery-Powered Precision Instrumentation Photodiode Preamps Active Filters 12- to 14-Bit Data Acquisition Systems Medical Instrumentation Low Power References and Regulators PRODUCT DESCRIPTION The AD822 is a dual precision, low power FET input op amp that can operate from a single supply of 3.0 V to 36 V or dual supplies of ± 1.5 V to ± 18 V. It has true single-supply capability The AD822 is available in two performance grades. The A and B grades are rated over the industrial temperature range of –40∞C to +85∞C. The AD822 is offered in three varieties of 8-lead packages: Plastic DIP, MSOP, and SOIC. 100 INPUT VOLTAGE NOISE – nV/ HZ 1V 100 5V 1V 20µs .... .... .... .... .... .... .... .... .... .... 90 . 10 VOUT 10 0% 0V (GND) 1 10 100 1k FREQUENCY – Hz .... .... .... .... .... .... .... .... .... .... 1V 10k Figure 1. Input Voltage Noise vs. Frequency Figure 2. Gain-of-2 Amplifier; VS = 5, 0, VIN = 2.5 V Sine Centered at 1.25 V, RL = 100 kW REV. D 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. 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 © Analog Devices, Inc., 2002 AD822–SPECIFICATIONS (V = 0, 5 V @ T = 25C, V S Parameter DC PERFORMANCE Initial Offset Max Offset over Temperature Offset Drift Input Bias Current at TMAX Input Offset Current at TMAX Open-Loop Gain Conditions VO = 0.2 V to 4 V RL = 100 kW RL = 10 kW TMIN to TMAX RL = 1 kW TMIN to TMAX DYNAMIC PERFORMANCE Unity Gain Frequency Full Power Response Slew Rate Settling Time to 0.1% to 0.01% MATCHING CHARACTERISTICS Initial Offset Max Offset over Temperature Offset Drift Input Bias Current Crosstalk @ f = 1 kHz f = 100 kHz INPUT CHARACTERISTICS Common-Mode Voltage Range1 TMIN to TMAX CMRR TMIN to TMAX Input Impedance Differential Common Mode OUTPUT CHARACTERISTICS Output Saturation Voltage2 VOL–VEE TMIN to TMAX VCC–VOH TMIN to TMAX VOL–VEE TMIN to TMAX VCC–VOH TMIN to TMAX VOL–VEE TMIN to TMAX VCC–VOH TMIN to TMAX Operating Output Current TMIN to TMAX Capacitive Load Drive POWER SUPPLY Quiescent Current TMIN to TMAX Power Supply Rejection TMIN to TMAX Min CM = 0 V, VOUT = 0.2 V, unless otherwise noted.) AD822A Typ 0.1 0.5 2 2 0.5 2 0.5 VCM = 0 V to 4 V TMIN to TMAX NOISE/HARMONIC PERFORMANCE Input Voltage Noise 0.1 Hz to 10 Hz f = 10 Hz f = 100 Hz f = 1 kHz f = 10 kHz Input Current Noise 0.1 Hz to 10 Hz f = 1 kHz Harmonic Distortion f = 10 kHz A 500 400 80 80 15 10 RL = 10 kW to 2.5 V VO = 0.25 V to 4.75 V VO p-p = 4.5 V VO = 0.2 V to 4.5 V Max Min 0.8 1.2 25 5 20 1000 500 400 80 80 15 10 150 30 AD822B Typ Max Unit 0.1 0.5 2 2 0.5 2 0.5 mV mV mV/∞C pA nA pA nA 150 30 2 25 21 16 13 mV p-p nV/÷Hz nV/÷Hz nV/÷Hz nV/÷Hz 18 0.8 18 0.8 fA p-p fA/÷Hz –93 –93 dB 1.8 210 3 1.8 210 3 MHz kHz V/ms 1.4 1.8 1.4 1.8 ms ms 0.5 1.3 3 20 VCM = 0 V to 2 V 10 –130 –93 –130 –93 +4 +4 80 –0.2 –0.2 69 66 1013储0.5 1013储2.8 ISINK = 20 mA 5 ISOURCE = 20 mA 10 ISINK = 2 mA 40 ISOURCE = 2 mA 80 ISINK = 15 mA 300 ISOURCE = 15 mA 800 7 10 14 20 55 80 110 160 500 1000 1500 1900 –2– 80 5 10 40 80 300 800 1.24 80 70 70 1.24 80 V V dB dB 7 10 14 20 55 80 110 160 500 1000 1500 1900 mV mV mV mV mV mV mV mV mV mV mV mV mA mA pF 1.6 mA dB dB 350 1.6 mV mV mV/∞C pA dB dB W储pF W储pF 15 12 350 66 66 +4 +4 1013储0.5 1013储2.8 15 12 VS+ = 5 V to 15 V V/mV V/mV V/mV V/mV V/mV V/mV 2 25 21 16 13 3 –0.2 –0.2 66 66 10 2.5 10 1000 1.0 1.6 RL = 5 kW 0.4 0.9 REV. D SPECIFICATIONS Parameter DC PERFORMANCE Initial Offset Max Offset over Temperature Offset Drift Input Bias Current at TMAX Input Offset Current at TMAX Open-Loop Gain Conditions VO = –4 V to +4 V RL = 100 kW RL = 10 kW TMIN to TMAX RL = 1 kW TMIN to TMAX NOISE/HARMONIC PERFORMANCE Input Voltage Noise 0.1 Hz to 10 Hz f = 10 Hz f = 100 Hz f = 1 kHz f = 10 kHz Input Current Noise 0.1 Hz to 10 Hz f = 1 kHz Harmonic Distortion f = 10 kHz DYNAMIC PERFORMANCE Unity Gain Frequency Full Power Response Slew Rate Settling Time to 0.1% to 0.01% MATCHING CHARACTERISTICS Initial Offset Max Offset over Temperature Offset Drift Input Bias Current Crosstalk @ f = 1 kHz f = 100 kHz INPUT CHARACTERISTICS Common-Mode Voltage Range1 TMIN to TMAX CMRR TMIN to TMAX Input Impedance Differential Common Mode OUTPUT CHARACTERISTICS Output Saturation Voltage2 VOL–VEE TMIN to TMAX VCC–VOH TMIN to TMAX VOL–VEE TMIN to TMAX VCC–VOH TMIN to TMAX VOL–VEE TMIN to TMAX VCC–VOH TMIN to TMAX Operating Output Current TMIN to TMAX Capacitive Load Drive POWER SUPPLY Quiescent Current TMIN to TMAX Power Supply Rejection TMIN to TMAX Min AD822A Typ 0.1 0.5 2 2 0.5 2 0.5 VCM = –5 V to +4 V TMIN to TMAX REV. D AD822 (VS = 5 V @ TA = 25C, VCM = 0 V, VOUT = 0 V, unless otherwise noted.) 400 400 80 80 20 10 Max Min 0.8 1.5 25 5 20 1000 400 400 80 80 20 10 150 30 AD822B Typ Max Unit 0.1 0.5 2 2 0.5 2 0.5 mV mV mV/∞C pA nA pA nA 0.4 1 10 2.5 10 1000 V/mV V/mV V/mV V/mV V/mV V/mV 150 30 2 25 21 16 13 2 25 21 16 13 mV p-p nV/÷Hz nV/÷Hz nV/÷Hz nV/÷Hz 18 0.8 18 0.8 fA p-p fA/÷Hz RL = 10 kW VO = ± 4.5 V –93 –93 dB VO p-p = 9 V 1.9 105 3 1.9 105 3 MHz kHz V/ms 1.4 1.8 1.4 1.8 ms ms VO = 0 V to ± 4.5 V 1.0 3 0.5 2 3 3 25 RL = 5 kW VCM = –5 V to +2 V 10 –130 –93 –5.2 –5.2 66 66 –130 –93 +4 +4 80 –5.2 –5.2 69 66 1013储0.5 1013储2.8 ISINK = 20 mA 5 ISOURCE = 20 mA 10 ISINK = 2 mA 40 ISOURCE = 2 mA 80 ISINK = 15 mA 300 ISOURCE = 15 mA 800 7 10 14 20 55 80 110 160 500 1000 1500 1900 5 10 40 80 300 800 –3– 1.3 80 7 10 14 20 55 80 110 160 500 1000 1500 1900 mV mV mV mV mV mV mV mV mV mV mV mV mA mA pF 1.6 mA dB dB 350 1.6 70 70 1.3 80 V V dB dB W储pF W储pF 15 12 350 66 66 80 1013储0.5 1013储2.8 15 12 VS+ = 5 V to 15 V +4 +4 mV mV mV/∞C pA dB dB AD822–SPECIFICATIONS (V = 15 V @ T = 25C, V S Parameter DC PERFORMANCE Initial Offset Max Offset over Temperature Offset Drift Input Bias Current at TMAX Input Offset Current at TMAX Open-Loop Gain A Conditions = 0 V, VOUT = 0 V, unless otherwise noted.) Min VO = +10 V to –10 V RL = 100 kW RL = 10 kW TMIN to TMAX RL = 1 kW AD822A Typ 0.4 0.5 2 2 40 0.5 2 0.5 VCM = 0 V VCM = –10 V VCM = 0 V TMIN to TMAX TMIN to TMAX NOISE/HARMONIC PERFORMANCE Input Voltage Noise 0.1 Hz to 10 Hz f = 10 Hz f = 100 Hz f = 1 kHz f = 10 kHz Input Current Noise 0.1 Hz to 10 Hz f = 1 kHz Harmonic Distortion f = 10 kHz DYNAMIC PERFORMANCE Unity Gain Frequency Full Power Response Slew Rate Settling Time to 0.1% to 0.01% MATCHING CHARACTERISTICS Initial Offset Max Offset over Temperature Offset Drift Input Bias Current Crosstalk @ f = 1 kHz f = 100 kHz INPUT CHARACTERISTICS Common-Mode Voltage Range1 TMIN to TMAX CMRR TMIN to TMAX Input Impedance Differential Common Mode OUTPUT CHARACTERISTICS Output Saturation Voltage2 VOL–VEE TMIN to TMAX VCC–VOH TMIN to TMAX VOL–VEE TMIN to TMAX VCC–VOH TMIN to TMAX VOL–VEE TMIN to TMAX VCC–VOH TMIN to TMAX Operating Output Current TMIN to TMAX Capacitive Load Drive POWER SUPPLY Quiescent Current TMIN to TMAX Power Supply Rejection TMIN to TMAX CM 500 500 100 100 30 20 Max Min 2 3 0.3 0.5 2 2 40 0.5 2 0.5 25 5 20 2000 500 500 100 100 30 20 500 45 AD822B Typ Max Unit 1.5 2.5 mV mV mV/∞C pA pA nA pA nA 12 2.5 12 2000 V/mV V/mV V/mV V/mV V/mV V/mV 500 45 2 25 21 16 13 2 25 21 16 13 mV p-p nV/÷Hz nV/÷Hz nV/÷Hz nV/÷Hz 18 0.8 18 0.8 fA p-p fA/÷Hz RL = 10 kW VO = ± 10 V –85 –85 dB VO p-p = 20 V 1.9 45 3 1.9 45 3 MHz kHz V/ms 4.1 4.5 4.1 4.5 ms ms VO = 0 V to ± 10 V 3 4 2 2.5 3 3 25 RL = 5 kW VCM = –15 V to +12 V 12 –130 –93 –15.2 –15.2 70 70 –130 –93 +14 +14 80 –15.2 –15.2 74 74 1013储0.5 1013储2.8 ISINK = 20 mA 5 ISOURCE = 20 mA 10 ISINK = 2 mA 40 ISOURCE = 2 mA 80 ISINK = 15 mA 300 ISOURCE = 15 mA 800 7 10 14 20 55 80 110 160 500 1000 1500 1900 5 10 40 80 300 800 –4– 1.4 80 7 10 14 20 55 80 110 160 500 1000 1500 1900 mV mV mV mV mV mV mV mV mV mV mV mV mA mA pF 1.8 mA dB dB 350 1.8 70 70 1.4 80 V V dB dB W储pF W储pF 20 15 350 70 70 90 1013储0.5 1013储2.8 20 15 VS+ = 5 V to 15 V +14 +14 mV mV mV/∞C pA dB dB REV. D SPECIFICATIONS (V = 0, 3 V @ T = 25ⴗC, V S Parameter DC PERFORMANCE Initial Offset Max Offset over Temperature Offset Drift Input Bias Current at TMAX Input Offset Current at TMAX Open-Loop Gain NOISE/HARMONIC PERFORMANCE Input Voltage Noise 0.1 Hz to 10 Hz f = 10 Hz f = 100 Hz f = 1 kHz f = 10 kHz Input Current Noise 0.1 Hz to 10 Hz f = 1 kHz Harmonic Distortion f = 10 kHz DYNAMIC PERFORMANCE Unity Gain Frequency Full Power Response Slew Rate Settling Time to 0.1% to 0.01% MATCHING CHARACTERISTICS Offset Drift Crosstalk @ f = 1 kHz f = 100 kHz INPUT CHARACTERISTICS CMRR Input Impedance Differential Common Mode OUTPUT CHARACTERISTICS Output Saturation Voltage2 VOL–VEE VCC–VOH VOL–VEE VCC–VOH VOL–VEE VCC–VOH Capacitive Load Drive POWER SUPPLY Quiescent Current Power Supply Rejection A CM = 0 V, VOUT = 0.2 V, unless otherwise noted.) AD822 Conditions Typ Unit VCM = 0 V to 2 V 0.2 0.5 1 2 0.5 2 0.5 mV mV mV/∞C pA nA pA nA 1000 150 30 V/mV V/mV V/mV 2 25 21 16 13 mV p-p nV/÷Hz nV/÷Hz nV/÷Hz nV/÷Hz 18 0.8 fA p-p fA/÷Hz RL = 10 kW to 1.5 V VO = ± 1.25 V –92 dB VO p-p = 2.5 V 1.5 240 3 MHz kHz V/ms 1 1.4 ms ms 2 –130 –93 mV/∞C dB dB VO = 0.2 V to 2 V RL = 100 kW RL = 10 kW RL = 1 kW VO = 0.2 V to 2.5 V RL = 5 kW VCM = 0 V to 1 V 74 1013储0.5 1013储2.8 ISINK = 20 mA ISOURCE = 20 mA ISINK = 2 mA ISOURCE = 2 mA ISINK = 10 mA ISOURCE = 10 mA VS+ = 3 V to 15 V dB W储pF W储pF 5 10 40 80 200 500 350 mV mV mV mV mV mV pF 1.24 80 mA dB NOTES 1 This is a functional specification. Amplifier bandwidth decreases when the input common-mode voltage is driven in the range (+V S – 1 V) to +VS. Common-mode error voltage is typically less than 5 mV with the common-mode voltage set at 1 V below the positive supply. 2 VOL–VEE is defined as the difference between the lowest possible output voltage (V OL) and the minus voltage supply rail (V EE). VCC–VOH is defined as the difference between the highest possible output voltage (V OH) and the positive supply voltage (V CC). Specifications subject to change without notice. REV. D –5– AD822 AD822 ABSOLUTE MAXIMUM RATINGS1 Supply Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ± 18 V Internal Power Dissipation2 Plastic DIP (N) . . . . . . . . . . . . . . Observe Derating Curves SOIC (R) . . . . . . . . . . . . . . . . . . . Observe Derating Curves Input Voltage . . . . . . . . . . . . . . (+VS + 0.2 V) to –(20 V + VS) Output Short Circuit Duration . . . . . . . . . . . . . . . . Indefinite Differential Input Voltage . . . . . . . . . . . . . . . . . . . . . . ± 30 V Storage Temperature Range (N) . . . . . . . . . –65∞C to +125∞C Storage Temperature Range (R, RM) . . . . . –65∞C to +150∞C Operating Temperature Range AD822A/AD822B . . . . . . . . . . . . . . . . . . –40∞C to +85∞C Lead Temperature Range (Soldering 60 sec) . . . . . . . . 260∞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 8-Lead Plastic DIP Package: qJA = 90∞C/W 8-Lead SOIC Package: qJA = 160∞C/W 8-Lead MSOP Package: qJA = 190∞C/W MAXIMUM POWER DISSIPATION The maximum power that can be safely dissipated by the AD822 is limited by the associated rise in junction temperature. For plastic packages, the maximum safe junction temperature is 145∞C. If these maximums are exceeded momentarily, proper circuit operation will be restored as soon as the die temperature is reduced. Leaving the device in the “overheated” condition for an extended period can result in device burnout. To ensure proper operation, it is important to observe the derating curves shown in TPC 24. While the AD822 is internally short circuit protected, this may not be sufficient to guarantee that the maximum junction temperature is not exceeded under all conditions. With power supplies ± 12 V (or less) at an ambient temperature of 25∞C or less, if the output node is shorted to a supply rail, then the amplifier will not be destroyed, even if this condition persists for an extended period. ORDERING GUIDE Package Branding Model* Temperature Range Package Description Option Information AD822AN AD822AR AD822ARM AD822BR –40∞C to +85∞C –40∞C to +85∞C –40∞C to +85∞C –40∞C to +85∞C 8-Lead PDIP 8-Lead SOIC 8-Lead MSOP 8-Lead SOIC N-8 RN-8 RM-8 RN-8 B4A *SPICE model is available at www.analog.com. 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 AD822 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. –6– WARNING! ESD SENSITIVE DEVICE REV. D Typical Performance Characteristics–AD822 70 5 VS = 0V, 5V 50 INPUT BIAS CURRENT – pA NUMBER OF UNITS 60 40 30 20 10 0 –0.5 –0.4 –0.3 –0.2 –0.1 0 0.1 0.2 OFFSET VOLTAGE – mV 0.3 0.4 VS = 0V, +5V, AND 5V VS = 5V –5 –5 0.5 –4 –3 –2 –1 0 1 2 COMMON-MODE VOLTAGE – V 3 4 5 TPC 4. Input Bias Current vs. Common-Mode Voltage; VS = 5 V, 0 V, and VS = ± 5 V TPC 1. Typical Distribution of Offset Voltage (390 Units) 1k 16 VS = 5V 14 INPUT BIAS CURRENT – pA VS = 15V 12 10 % IN BIN 0 8 6 4 100 10 1 2 0 –12 –10 –8 –6 –4 –2 0 2 4 OFFSET VOLTAGE DRIFT – V/C 6 8 0.1 –16 10 –12 –8 –4 0 4 8 COMMON-MODE VOLTAGE – V 12 16 TPC 5. Input Bias Current vs. Common-Mode Voltage; VS = ± 15 V TPC 2. Typical Distribution of Offset Voltage Drift (100 Units) 100k 50 45 10k INPUT BIAS CURRENT – pA 40 NUMBER OF UNITS 35 30 25 20 15 10 1k 100 10 1 5 0.1 20 0 0 1 2 3 4 5 6 7 INPUT BIAS CURRENT – pA 8 9 10 60 80 100 TEMPERATURE – C 120 140 TPC 6. Input Bias Current vs. Temperature; VS = 5 V, VCM = 0 TPC 3. Typical Distribution of Input Bias Current (213 Units) REV. D 40 –7– AD822 10M 40 1M VS = 0V, 5V VS = 0V, 3V 100k RL = 20k 20 INPUT VOLTAGE – V 0PEN-LOOP GAIN – V/V VS = 15V POS RAIL RL = 2k NEG RAIL POS RAIL 0 POS RAIL –20 NEG RAIL RL = 100k 10k 100 1k 10k LOAD RESISTANCE – –40 100k 60 120 180 240 OUTPUT VOLTAGE FROM SUPPLY RAILS – mV 300 TPC 10. Input Error Voltage with Output Voltage within 300 mV of Either Supply Rail for Various Resistive Loads; VS = ± 5 V TPC 7. Open-Loop Gain vs. Load Resistance 1k RL = 100k INPUT VOLTAGE NOISE – nV/ HZ 10M OPEN-LOOP GAIN – V/V NEG RAIL 0 VS = 15V 1M VS = 0V, 5V VS = 15V RL = 10k VS = 0V, 5V 100k VS = 15V RL = 600 100 10 VS = 0V, 5V 10k –60 –40 –20 0 20 40 60 80 TEMPERATURE – C 100 120 1 1 140 10 100 FREQUENCY – Hz 1k 10k TPC 11. Input Voltage Noise vs. Frequency TPC 8. Open-Loop Gain vs. Temperature –40 300 –50 200 RL = 10k ACL = –1 RL = 10k RL = 100k THD – dB INPUT VOLTAGE – V –60 100 0 –100 –70 –80 –90 RL = 600 VS = 0V, 3V; VOUT = 2.5V p-p VS = 15V; VOUT = 20V p-p VS = 5V; VOUT = 9V p-p –200 –100 –300 –16 VS = 0V, 5V; VOUT = 4.5V p-p –110 100 1k 10k FREQUENCY – Hz –12 –8 –4 0 4 OUTPUT VOLTAGE – V 8 12 16 100k TPC 12. Total Harmonic Distortion vs. Frequency TPC 9. Input Error Voltage vs. Output Voltage for Resistive Loads –8– REV. D AD822 100 100 80 80 90 60 60 GAIN 40 40 20 20 RL = 2k CL = 100pF 0 –20 10 0 10k 100k FREQUENCY – Hz 1M –20 10M 50 VS = 0V, 5V VS = 0V, 3V 40 30 20 100 1k 10k 100k FREQUENCY – Hz 1M 10M TPC 16. Common-Mode Rejection vs. Frequency 5 1k COMMON-MODE ERROR VOLTAGE – mV ACL = +1 VS = 15V 100 OUTPUT IMPEDANCE – 60 0 10 TPC 13. Open-Loop Gain and Phase Margin vs. Frequency 10 1 0.1 0.01 100 VS = 15V 70 10 1k 100 PHASE MARGIN IN DEGREES OPEN-LOOP GAIN – dB PHASE COMMON-MODE REJECTION – dB 80 10k 100k FREQUENCY – Hz 1k 1M NEGATIVE RAIL 4 3 +25C 2 +125C –55C 1 –55C +125C 0 –1 10M POSITIVE RAIL 0 1 2 COMMON-MODE VOLTAGE FROM SUPPLY RAILS – V 3 TPC 17. Absolute Common-Mode Error vs. CommonMode Voltage from Supply Rails (VS – VCM) TPC 14. Output Impedance vs. Frequency 16 1000 8 OUTPUT SATURATION VOLTAGE – mV OUTPUT SWING FROM 0 TO VOLTS 12 1% 4 0.01% ERROR 0.1% 0 0.01% –4 –8 1% –12 –16 0.0 1.0 2.0 3.0 SETTLING TIME – s 4.0 VS – VOH VOL – VS 10 0 5.0 0.001 0.01 0.1 1 LOAD CURRENT – mA 10 100 TPC 18. Output Saturation Voltage vs. Load Current TPC 15. Output Swing and Error vs. Settling Time REV. D 100 –9– AD822 100 1000 90 POWER SUPPLY REJECTION – dB OUTPUT SATURATION VOLTAGE – mV ISOURCE = 10mA ISINK = 10mA 100 ISOURCE = 1mA ISINK = 1mA ISOURCE = 10A 10 ISINK = 10A 1 –60 –40 –20 0 60 20 40 80 TEMPERATURE – C 100 120 +PSRR 60 50 40 –PSRR 30 20 10 100 1k 10k 100k FREQUENCY – Hz 1M 10M TPC 22. Power Supply Rejection vs. Frequency 30 80 70 VS = 15V RL = 2k 25 VS = 15V 60 50 OUTPUT VOLTAGE – V SHORT CIRCUIT CURRENT LIMIT – mA 70 0 10 140 TPC 19. Output Saturation Voltage vs. Temperature –OUT VS = 15V 40 VS = 0V, 5V 30 + VS = 0V, 3V – – 20 VS = 0V, 5V 10 + + VS = 0V, 3V 20 15 10 5 VS = 0V, 5V VS = 0V, 3V 0 –60 –40 –20 0 20 40 60 80 TEMPERATURE – C 100 120 0 10k 140 10M 2.4 1600 2.2 T = +125C TOTAL POWER DISSIPATION – W 1400 T = +25C 1200 T = –55C 1000 800 600 400 200 0 1M 100k FREQUENCY – Hz TPC 23. Large Signal Frequency Response TPC 20. Short Circuit Current Limit vs. Temperature QUIESCENT CURRENT – A 80 2.0 1.8 8-LEAD MINI-DIP 8-LEAD SOIC 1.6 1.4 1.2 1.0 0.8 0.6 8-LEAD MSOP 0.4 0.2 0 4 8 12 16 20 24 28 TOTAL SUPPLY VOLTAGE – V 32 0.0 –60 36 TPC 21. Quiescent Current vs. Supply Voltage vs. Temperature –40 –20 0 20 40 AMBIENT TEMPERATURE – C 60 80 TPC 24. Maximum Power Dissipation vs. Temperature for Plastic Packages –10– REV. D AD822 –70 VOUT +VS –80 20k 0.1F CROSSTALK – dB –90 2 20V p-p –100 1 1/2 AD822 6 7 3 5k 1/2 AD822 –110 1F 8 2.2k 5 5k VIN –120 CROSSTALK = 20LOG VOUT 10VIN 0.1F 1F –VS –130 –140 300 3k 1k 10k 30k FREQUENCY – Hz 100k 300k 1M TPC 25. Crosstalk vs. Frequency TPC 28. Crosstalk Test Circuit 5V 5µs 100 1/2 AD822 +VS 90 0.01F 8 VIN 0.01F 4 100pF RL VOUT 10 0% TPC 26. Unity Gain Follower 5V TPC 29. Large Signal Response Unity Gain Follower; VS = ± 15 V, RL = 10 kW 10mV 10µs 100 100 90 90 10 10 0% 0% TPC 30. Small Signal Response Unity Gain Follower; VS = ± 15 V, RL = 10 kW TPC 27. 20 V p-p, 25 kHz Sine Wave Input; Unity Gain Follower; RL = 600 W, VS = ± 15 V REV. D 500ns –11– AD822 1V 2µs 1V 100 100 90 90 10 GND 2µs 10 0% GND 0% TPC 34. VS = 5 V, 0 V; Unity Gain Follower Response to 0 V to 5 V Step TPC 31. VS = 5 V, 0 V; Unity Gain Follower Response to 0 V to 4 V Step 10mV 2µs 100 90 +VS 0.01F 8 VIN 4 1/2 AD822 100pF RL VOUT 10 GND TPC 32. Unity Gain Follower 0% TPC 35. VS = 5 V, 0 V; Unity Gain Follower Response, to 40 mV Step Centered 40 mV Above Ground, RL = 10 kW 10mV VIN 10k 2µs 100 20k +VS 90 VOUT 0.01F 8 4 1/2 AD822 RL 100pF 10 GND TPC 33. Gain-of-Two Inverter 0% TPC 36. VS = 5 V, 0 V; Gain-of-Two Inverter Response to 20 mV Step, Centered 20 mV Below Ground, RL = 10 kW –12– REV. D AD822 1V 1V 2µs 100 100 10µs .... .... .... .... .... .... .... .... .... .... 90 90 10 10 GND GND 0% .... .... .... .... .... .... .... .... .... .... 0% 1V (a) TPC 37. VS = 5 V, 0 V; Gain-of-Two Inverter Response to 2.5 V Step Centered –1.25 V Below Ground, RL = 10 kW +VS 500mV 100 10µs 1V 1V .... .... .... .... .... .... .... .... .... .... 90 10µs 100 90 10 GND 0% .... .... .... .... .... .... .... .... .... .... 1V 10 GND (b) 0% 5V RP TPC 38. VS = 3 V, 0 V; Gain-of-Two Inverter, VIN = 1.25 V, 25 kHz, Sine Wave Centered at –0.75 V, RL = 600 W VIN VOUT TPC 39. (a) Response with RP = 0; VIN from 0 to +VS (b) VIN = 0 to +VS + 200 mV VOUT = 0 to +VS RP = 49.9 kW APPLICATION NOTES INPUT CHARACTERISTICS In the AD822, n-channel JFETs are used to provide a low offset, low noise, high impedance input stage. Minimum input commonmode voltage extends from 0.2 V below –VS to 1 V less than +VS. Driving the input voltage closer to the positive rail will cause a loss of amplifier bandwidth (as can be seen by comparing the large signal responses shown in TPCs 31 and 34) and increased common-mode voltage error as illustrated in TPC 17. The AD822 does not exhibit phase reversal for input voltages up to and including +VS. TPC 39a shows the response of an AD822 voltage follower to a 0 V to 5 V (+VS) square wave input. The input and output are superimposed. The output tracks the input up to +VS without phase reversal. The reduced bandwidth above a 4 V input causes the rounding of the output wave form. For REV. D input voltages greater than +VS, a resistor in series with the AD822’s noninverting input will prevent phase reversal, at the expense of greater input voltage noise. This is illustrated in TPC 39b. Since the input stage uses n-channel JFETs, input current during normal operation is negative; the current flows out from the input terminals. If the input voltage is driven more positive than +VS – 0.4 V, the input current will reverse direction as internal device junctions become forward biased. This is illustrated in TPC 4. A current limiting resistor should be used in series with the input of the AD822 if there is a possibility of the input voltage exceeding the positive supply by more than 300 mV, or if an input voltage will be applied to the AD822 when ±VS = 0. The amplifier will be damaged if left in that condition for more than 10 seconds. A 1 kW resistor allows the amplifier to withstand up to 10 V of continuous overvoltage and increases the input voltage noise by a negligible amount. –13– AD822 Input voltages less than –VS are a completely different story. The amplifier can safely withstand input voltages 20 V below the minus supply voltage as long as the total voltage from the positive supply to the input terminal is less than 36 V. In addition, the input stage typically maintains picoamp level input currents across that input voltage range. 20mV 100 2µs .... .... .... .... .... .... .... .... .... .... 90 The AD822 is designed for 13 nV/÷Hz wideband input voltage noise and maintains low noise performance to low frequencies (refer to TPC 11). This noise performance, along with the AD822’s low input current and current noise, means that the AD822 contributes negligible noise for applications with source resistances greater than 10 kW and signal bandwidths greater than 1 kHz. This is illustrated in Figure 3. 10 0% .... .... .... .... .... .... .... .... .... .... 100k 10k Figure 4. Small Signal Response of AD822 as Unity Gain Follower Driving 350 pF WHENEVER JOHNSON NOISE IS GREATER THAN AMPLIFIER NOISE, AMPLIFIER NOISE CAN BE CONSIDERED NEGLIGIBLE FOR APPLICATION. INPUT VOLTAGE NOISE – V 1kHz Figure 5 is a plot of capacitive load that will result in a 20 degree phase margin versus noise gain for the AD822. Noise gain is the inverse of the feedback attenuation factor provided by the feedback network in use. 1k RESISTOR JOHNSON NOISE 100 5 10 10Hz 1 0.1 10k 100k 10M 100M 1M SOURCE IMPEDANCE – 1G RF NOISE GAIN – 1+ –––– R1 AMPLIFIER-GENERATED NOISE 10G Figure 3. Total Noise vs. Source Impedance OUTPUT CHARACTERISTICS 4 3 2 The AD822’s unique bipolar rail-to-rail output stage swings within 5 mV of the minus supply and 10 mV of the positive supply with no external resistive load. The AD822’s approximate output saturation resistance is 40 W sourcing and 20 W sinking. This can be used to estimate output saturation voltage when driving heavier current loads. For instance, when sourcing 5 mA, the saturation voltage to the positive supply rail will be 200 mV; when sinking 5 mA, the saturation voltage to the minus rail will be 100 mV. 1 300 1k 3k 10k CAPACITIVE LOAD FOR 20 O PHASE MARGIN – pF RF 30k CL The amplifier’s open-loop gain characteristic will change as a function of resistive load, as shown in TPCs 7 through 10. For load resistances over 20 kW, the AD822’s input error voltage is virtually unchanged until the output voltage is driven to 180 mV of either supply. Figure 5. Capacitive Load Tolerance vs. Noise Gain If the AD822’s output is overdriven so as to saturate either of the output devices, the amplifier will recover within 2 ms of its input returning to the amplifier’s linear operating region. Figure 6 shows a method for extending capacitance load drive capability for a unity gain follower. With these component values, the circuit will drive 5,000 pF with a 10% overshoot. R1 Direct capacitive loads will interact with the amplifier’s effective output impedance to form an additional pole in the amplifier’s feedback loop which can cause excessive peaking on the pulse response or loss of stability. Worst case is when the amplifier is used as a unity gain follower. Figure 4 shows the AD822’s pulse response as a unity gain follower driving 350 pF. This amount of overshoot indicates approximately 20 degrees of phase margin— the system is stable but is nearing the edge. Configurations with less loop gain, and as a result less loop bandwidth, will be much less sensitive to capacitance load effects. +VS 0.01F 8 VIN 100 1/2 AD822 0.01F 4 VOUT CL –VS 20pF 20k Figure 6. Extending Unity Gain Follower Capacitive Load Capability Beyond 350 pF –14– REV. D AD822 APPLICATIONS Single-Supply Voltage-to-Frequency Converter Table I. In Amp Performance The circuit shown in Figure 7 uses the AD822 to drive a low power timer that produces a stable pulse of width t1. The positive going output pulse is integrated by R1–C1 and used as one input to the AD822 that is connected as a differential integrator. The other input (nonloading) is the unknown voltage, VIN. The AD822 output drives the timer trigger input, closing the overall feedback loop. +10V C5 0.1F 2 6 U4 REF02 VREF = 5V 5 3 4 CMOS 74HCO4 RSCALE** 10k 4 R2 499k 1% U3B VIN OUT1 0.01F, 2% U1 C1 R3* 116k 6 2 AD822B 7 499k 1% C2 0.01F, 2% 0V TO 2.5V FULL SCALE 1 OUT2 VS = 3 V, 0 V VS = 5 V CMRR Common-Mode Voltage Range 3 dB BW, G = 10 G = 100 tSETTLING 2 V Step (VS = 0 V, 3 V) 5 V (VS = ± 5 V) Noise @ f = 1 kHz, G = 10 G = 100 ISUPPLY (Total) 74 dB 80 dB –0.2 V to +2 V –5.2 V to +4 V 180 kHz 180 kHz 18 kHz 18 kHz 2 ms 5 ms 270 nV/÷Hz 2.2 mV/÷Hz 1.15 mA 270 nV/÷Hz 2.2 mV/÷Hz 1.10 mA U2 CMOS 555 1/2 R1 C3 0.1F U3A 3 2 Parameters 4 R THR 8 V+ OUT TR DIS GND 1 CV 5µs 3 100 .... .... .... .... .... .... .... .... .... .... 90 5 . C4 0.01F NOTES fOUT = VIN/(VREFt1 ), t1 = 1.1R3C6 = * = ** = t1 = 10 25kHz FS AS SHOWN 1% METAL FILM, <50ppm/C TC 10% 20T FILM, <100ppm/C TC 33s FOR fOUT = 20kHz @ VIN = 2.0V 0% .... .... .... .... .... .... .... .... .... .... 1V Figure 7. Single-Supply Voltage-to-Frequency Converter Figure 8a. Pulse Response of In Amp to a 500 mV p-p Input Signal; VS = 5 V, 0 V; Gain = 10 Typical AD822 bias currents of 2 pA allow Megohm-range source impedances with negligible dc errors. Linearity errors on the order of 0.01% full scale can be achieved with this circuit. This performance is obtained with a 5 V single supply which delivers less than 1 mA to the entire circuit. R1 90k Single-Supply Programmable Gain Instrumentation Amplifier R2 9k R3 1k R4 1k R5 9k R6 90k VREF The AD822 can be configured as a single-supply instrumentation amplifier that is able to operate from single supplies down to 3 V or dual supplies up to ±15 V. Using only one AD822 rather than three separate op amps, this circuit is cost and power efficient. AD822 FET inputs’ 2 pA bias currents minimize offset errors caused by high unbalanced source impedances. G = 10 G = 100 G = 100 G = 10 +VS 0.1F 6 2 An array of precision thin-film resistors sets the in amp gain to be either 10 or 100. These resistors are laser trimmed to ratio match to 0.01% and have a maximum differential TC of 5 ppm/∞C. VIN1 VIN2 RP 1k 3 1/2 AD822 RP 1k 1 5 1/2 AD822 7 4 (G = 10) R6 VOUT = (VIN1 – VIN2) 1+ –––––––– +VREF R4 + R5 (G = 100) R5 + R6 VOUT = (VIN1 – VIN2) 1+ –––––––– +VREF R4 Figure 8b. A Single-Supply Programmable Instrumentation Amplifier REV. D OHMTEK PART # 1043 –15– VOUT AD822 3 V, Single-Supply Stereo Headphone Driver Low Dropout Bipolar Bridge Driver The AD822 exhibits good current drive and THD + N performance, even at 3 V single supplies. At 1 kHz, total harmonic distortion plus noise (THD + N) equals –62 dB (0.079%) for a 300 mV p-p output signal. This is comparable to other single- supply op amps that consume more power and cannot run on 3 V power supplies. 3V 1F MYLAR 0.1F 95.3k + 0.1F CHANNEL 1 47.5k 1/2 AD822 The AD822 can be used for driving a 350 W Wheatstone bridge. Figure 10 shows one half of the AD822 being used to buffer the AD589—a 1.235 V low power reference. The output of 4.5 V can be used to drive an A/D converter front end. The other half of the AD822 is configured as a unity gain inverter and generates the other bridge input of –4.5 V. Resistors R1 and R2 provide a constant current for bridge excitation. The AD620 low power instrumentation amplifier is used to condition the differential output voltage of the bridge. The gain of the AD620 is programmed using an external resistor RG and determined by: 500F G= 4.99k 95.3k L 10k +Vs HEADPHONES 32 IMPEDANCE 10k 49.9k 4.99k R 1F MYLAR 47.5k R1 20 +1.235V AD589 CHANNEL 2 49.4 kW +1 RG 1/2 AD822 1/2 AD822 TO A/D CONVERTER REFERENCE INPUT 25.4k 1% 500F 10k 1% Figure 9. 3 V Single-Supply Stereo Headphone Driver 350 350 In Figure 9, each channel’s input signal is coupled via a 1 mF Mylar capacitor. Resistor dividers set the dc voltage at the noninverting inputs so that the output voltage is midway between the power supplies (1.5 V). The gain is 1.5. Each half of the AD822 can then be used to drive a headphone channel. A 5 Hz high-pass filter is realized by the 500 mF capacitors and the headphones that can be modeled as 32 W load resistors to ground. This ensures that all signals in the audio frequency range (20 Hz–20 kHz) are delivered to the headphones. +VS 350 350 10k 1% 10k 1% 1/2 AD822 RG AD620 VREF –VS –4.5V R2 20 +Vs +Vs + 0.1F GND + 0.1F –Vs + + +5V 1F 1F –5V Figure 10. Low Dropout Bipolar Bridge Driver –16– REV. D AD822 OUTLINE DIMENSIONS 8-Lead Standard Small Outline Package [SOIC] Narrow Body (RN-8) 8-Lead Plastic Dual-in-Line Package [PDIP] (N-8) Dimensions shown in inches and (millimeters) Dimensions shown in millimeters and (inches) 0.375 (9.53) 0.365 (9.27) 0.355 (9.02) 8 1 5 4 5.00 (0.1968) 4.80 (0.1890) 0.295 (7.49) 0.285 (7.24) 0.275 (6.98) 0.325 (8.26) 0.310 (7.87) 0.300 (7.62) 0.100 (2.54) BSC 0.180 (4.57) MAX 0.150 (3.81) 0.130 (3.30) 0.110 (2.79) 0.022 (0.56) 0.018 (0.46) 0.014 (0.36) 4.00 (0.1574) 3.80 (0.1497) 0.150 (3.81) 0.135 (3.43) 0.120 (3.05) 0.015 (0.38) MIN 8 5 1 4 1.27 (0.0500) BSC 0.25 (0.0098) 0.10 (0.0040) 0.015 (0.38) 0.010 (0.25) 0.008 (0.20) SEATING PLANE 0.060 (1.52) 0.050 (1.27) 0.045 (1.14) COPLANARITY SEATING 0.10 PLANE 1.75 (0.0688) 1.35 (0.0532) 0.51 (0.0201) 0.33 (0.0130) 0.50 (0.0196) ⴛ 45ⴗ 0.25 (0.0099) 8ⴗ 0.25 (0.0098) 0ⴗ 1.27 (0.0500) 0.41 (0.0160) 0.19 (0.0075) COMPLIANT TO JEDEC STANDARDS MS-012AA 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 COMPLIANT TO JEDEC STANDARDS MO-095AA CONTROLLING DIMENSIONS ARE IN INCHES; MILLIMETERS DIMENSIONS (IN PARENTHESES) 8-Lead MSOP Package [MSOP] (RM-8) Dimensions shown in millimeters 3.00 BSC 8 5 4.90 BSC 3.00 BSC 1 4 PIN 1 0.65 BSC 1.10 MAX 0.15 0.00 0.38 0.22 COPLANARITY 0.10 0.23 0.08 8ⴗ 0ⴗ SEATING PLANE COMPLIANT TO JEDEC STANDARDS MO-187AA REV. D 6.20 (0.2440) 5.80 (0.2284) –17– 0.80 0.40 AD822 Revision History Location Page 10/02—Data sheet changed from REV. C to REV. D Edits to FEATURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Edits to ORDERING GUIDE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Updated SOIC PACKAGE OUTLINE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 8/02—Data sheet changed from REV. B to REV. C All figures updated . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Global Edits to FEATURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Updated all PACKAGE OUTLINES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 7/01—Data sheet changed from REV. A to REV. B All figures updated . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Global Cerdip references removed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1, 6, and 18 Additions to Product Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1 8-Lead SOIC and 8-Lead MSOP Diagrams added . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Deletion of AD822S column . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2 Edits to Absolute Maximum Ratings and Ordering Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Removed Metalization Photograph . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 –18– REV. D –19– –20– PRINTED IN U.S.A. C00874–0–10/02(D)