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 61.5 V to 618 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 mA Max Quiescent Current per Amplifier Unity Gain Bandwidth: 1.8 MHz Slew Rate of 3.0 V/ms GOOD DC PERFORMANCE 800 mV Max Input Offset Voltage 2 mV/8C Typ Offset Voltage Drift 25 pA Max Input Bias Current LOW NOISE 13 nV/Hz @ 10 kHz NO PHASE INVERSION 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 INPUT VOLTAGE NOISE - nV/Hz 100 CONNECTION DIAGRAM 8-Pin Plastic DIP, Cerdip and SOIC OUT1 1 8 V+ -IN1 2 7 OUT2 +IN1 3 6 -IN2 V- 4 5 +IN2 AD822 capability 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 V max, offset voltage drift of 2 V/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/s slew rate are provided with a low supply current of 800 A 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. This combination of ac and dc performance, plus the outstanding load drive capability, results in an exceptionally versatile amplifier for the single supply user. The AD822 is available in four performance grades. The A and B grades are rated over the industrial temperature range of -40C to +85C. There is also a 3 volt grade--the AD822A-3V, rated over the industrial temperature range. The mil grade is rated over the military temperature range of -55C to +125C and is available processed on standard military drawing. The AD822 is offered in three varieties of 8-pin package: plastic DIP, hermetic cerdip and surface mount (SOIC) as well as die form. 1V 1V 20 s 100 10 5V 90 VOUT 10 0% 1 10 100 1k FREQUENCY - Hz 10k Input Voltage Noise vs. Frequency REV. A 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 which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. 0V (GND) 1V Gain of +2 Amplifier; VS = +5, 0, VIN = 2.5 V Sine Centered at 1.25 Volts, RL = 100 k One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. Tel: 617/329-4700 Fax: 617/326-8703 AD822-SPECIFICATIONS (V = 0, 5 volts @ T = +258C, 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 k RL = 10 k TMIN to TMAX RL = 1 k 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 Range2 TMIN to TMAX CMRR TMIN to TMAX Input Impedance Differential Common Mode OUTPUT CHARACTERISTICS Output Saturation Voltage3 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 AD822A Typ Max 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 k 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 = 0 V, VOUT = 0.2 V unless otherwise noted) Min 0.8 1.2 0.1 0.5 2 2 0.5 2 0.5 25 5 20 1000 500 400 80 80 15 10 150 30 AD822B Typ Max 10 2.5 10 500 1000 150 80 150 30 15 30 0.8 25 20 mV mV V/C pA nA pA nA V/mV V/mV V/mV V/mV V/mV V/mV 2 25 21 16 13 2 25 21 16 13 V p-p nV/Hz nV/Hz nV/Hz nV/Hz 18 0.8 18 0.8 18 0.8 fA p-p fA/Hz -93 -93 -93 dB 1.8 210 3 1.8 210 3 1.8 210 3 MHz kHz V/s 1.4 1.8 1.4 1.8 1.4 1.8 s s 0.5 1.3 1.6 3 20 VCM = 0 V to +2 V 0.1 0.5 2 2 0.5 2 1.5 Units 2 25 21 16 13 3 10 -130 -93 -0.2 -0.2 66 66 0.4 0.9 AD822S1 Typ Max 1000 1.0 1.6 RL = 5 k Min 20 -130 -93 4 4 80 -0.2 -0.2 69 66 -130 -93 4 4 80 -0.2 66 4 80 mV mV V/C pA dB dB V V dB dB 1013||0.5 1013||2.8 1013||0.5 1013||2.8 1013||0.5 1013||2.8 ||pF ||pF ISINK = 20 A 5 5 5 7 ISOURCE = 20 A 10 10 14 ISINK = 2 mA 40 40 55 ISOURCE = 2 mA 80 80 110 ISINK = 15 mA 300 300 500 ISOURCE = 15 mA 800 800 1500 mV mV mV mV mV mV mV mV mV mV mV mV mA mA pF 7 10 14 20 55 80 110 160 500 1000 1500 1900 15 12 10 40 80 300 800 15 12 350 VS+ = 5 V to 15 V 70 70 -2- 7 10 14 20 55 80 110 160 500 1000 1500 1900 1.24 80 15 350 1.6 66 66 1.24 80 350 1.6 70 1.24 80 mA dB dB REV. A AD822 (VS = 65 volts @ TA = +258C, VCM = 0 V, VOUT = 0 V unless otherwise noted) 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 k RL = 10 k TMIN to TMAX RL = 1 k 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 Range2 TMIN to TMAX CMRR TMIN to TMAX Input Impedance Differential Common Mode OUTPUT CHARACTERISTICS Output Saturation Voltage3 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 REV. A AD822A Typ Max 0.1 0.5 2 2 0.5 2 0.5 VCM = -5 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 Min 400 400 80 80 20 10 RL = 10 k VO = 4.5 V VO p-p = 9 V VO = 0 V to 4.5 V Min 0.8 1.5 0.1 0.5 2 2 0.5 2 0.5 25 5 20 1000 400 400 80 80 20 10 150 30 AD822B Typ Max 10 2.5 10 400 1000 150 80 150 30 20 30 25 mV mV V/C pA nA pA nA V/mV V/mV V/mV V/mV V/mV V/mV 2 25 21 16 13 2 25 21 16 13 V p-p nV/Hz nV/Hz nV/Hz nV/Hz 18 0.8 18 0.8 18 0.8 fA p-p fA/Hz -93 -93 -93 dB 1.9 105 3 1.9 105 3 1.9 105 3 MHz kHz V/s 1.4 1.8 1.4 1.8 1.4 1.8 s s 0.5 2 1.6 2 3 25 VCM = -5 V to +2 V 0.1 0.5 2 2 0.5 2 1.5 Units 2 25 21 16 13 3 10 -130 -93 -5.2 -5.2 66 66 0.4 1 AD822S1 Typ Max 1000 1.0 3 RL = 5 k Min 25 -130 -93 4 4 80 -5.2 -5.2 69 66 -130 -93 4 4 80 -5.2 66 4 80 mV mV V/C pA dB dB V V dB dB 1013||0.5 1013||2.8 1013||0.5 1013||2.8 1013||0.5 1013||2.8 ||pF ||pF ISINK = 20 A 5 5 5 7 ISOURCE = 20 A 10 10 14 ISINK = 2 mA 40 40 55 ISOURCE = 2 mA 80 80 110 ISINK = 15 mA 300 300 500 ISOURCE = 15 mA 800 800 1500 mV mV mV mV mV mV mV mV mV mV mV mV mA mA pF 7 10 14 20 55 80 110 160 500 1000 1500 1900 15 12 10 40 80 300 800 15 12 350 VS+ = 5 V to 15 V 70 70 -3- 7 10 14 20 55 80 110 160 500 1000 1500 1900 1.3 80 15 350 1.6 66 66 1.3 80 350 1.6 70 1.3 80 mA dB dB AD822-SPECIFICATIONS (V = 615 volts @ T = +258C, 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 = +10 V to -10 V RL = 100 k RL = 10 k TMIN to TMAX RL = 1 k 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 Range2 TMIN to TMAX CMRR TMIN to TMAX Input Impedance Differential Common Mode OUTPUT CHARACTERISTICS Output Saturation Voltage3 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 AD822A Typ Max 0.4 0.5 2 2 40 0.5 2 0.5 VCM = 0 V VCM = -10 V VCM = 0 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 500 500 100 100 30 20 RL = 10 k VO = 10 V VO p-p = 20 V VO = 0 V to 10 V = 0 V, VOUT = 0 V unless otherwise noted) Min AD822B Typ Max 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 12 2.5 12 500 2000 500 150 400 45 30 45 2.0 25 20 mV mV V/C pA pA nA pA nA V/mV V/mV V/mV V/mV V/mV V/mV 2 25 21 16 13 2 25 21 16 13 V p-p nV/Hz nV/Hz nV/Hz nV/Hz 18 0.8 18 0.8 18 0.8 fA p-p fA/Hz -85 -85 -85 dB 1.9 45 3 1.9 45 3 1.9 45 3 MHz kHz V/s 4.1 4.5 4.1 4.5 4.1 4.5 s s 2 2.5 0.8 1.0 3 25 VCM = -15 V to 12 V 0.4 0.5 2 2 40 0.5 2 1.5 Units 2 25 21 16 13 3 12 -130 -93 -15.2 -15.2 70 70 1.5 2.5 AD822S1 Typ Max 2000 3 4 RL = 5 k Min 25 -130 -93 14 14 80 -15.2 -15.2 74 74 -130 -93 14 14 90 -15.2 70 14 90 mV mV V/C pA dB dB V V dB dB 1013||0.5 1013||2.8 1013||0.5 1013||2.8 1013||0.5 1013||2.8 ||pF ||pF ISINK = 20 A 5 5 5 7 ISOURCE = 20 A 10 10 14 ISINK = 2 mA 40 40 55 ISOURCE = 2 mA 80 80 110 ISINK = 15 mA 300 300 500 ISOURCE = 15 mA 800 800 1500 mV mV mV mV mV mV mV mV mV mV mV mV mA mA pF 7 10 14 20 55 80 110 160 500 1000 1500 1900 20 15 10 40 80 300 800 20 15 350 VS+ = 5 V to 15 V 7 10 14 20 55 80 110 160 500 1000 1500 1900 1.4 80 70 70 -4- 20 350 1.8 70 70 1.4 80 350 1.8 70 1.4 80 mA dB dB REV. A AD822 (VS = 0, 3 volts @ TA = +258C, VCM = 0 V, VOUT = 0.2 V unless otherwise noted) 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 Min 0.2 0.5 1 2 0.5 2 0.5 VCM = 0 V to +2 V VO = 0.2 V to 2 V RL = 100 k 300 300 60 60 10 8 TMIN to TMAX RL = 10 k TMIN to TMAX RL = 1 k 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 Range2 TMIN to TMAX CMRR TMIN to TMAX Input Impedance Differential Common Mode OUTPUT CHARACTERISTICS Output Saturation Voltage3 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 REV. A AD822A-3 V Typ RL = 10 k to 1.5 V VO = 1.25 V VO p-p = 2.5 V VO = 0.2 V to 2.5 V Max Units 1 1.5 mV mV V/C pA nA pA nA 25 5 20 1000 V/mV V/mV V/mV V/mV V/mV V/mV 150 30 2 25 21 16 13 V p-p nV/Hz nV/Hz nV/Hz nV/Hz 18 0.8 fA p-p fA/Hz -92 dB 1.5 240 3 MHz kHz V/s 1 1.4 s s 1 2 2 10 RL = 5 k -130 -93 -0.2 -0.2 60 60 VCM = 0 V to +1 V 2 2 74 1013||0.5 1013||2.8 ISINK = 20 A 5 ISOURCE = 20 A 10 ISINK = 2 mA 40 ISOURCE = 2 mA 80 ISINK = 10 mA 200 ISOURCE = 10 mA 500 7 10 14 20 55 80 110 160 400 400 1000 1000 mV mV mV mV mV mV mV mV mV mV mV mV mA mA pF 1.6 mA dB dB 350 70 70 -5- 1.24 80 V V dB dB ||pF ||pF 15 12 VS+ = 3 V to 15 V mV mV V/C pA dB dB AD822-SPECIFICATIONS AD822 NOTES 1 See standard military drawing for 883B specifications. 2 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 volt below the positive supply. 3 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. 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. ABSOLUTE MAXIMUM RATINGS 1 Supply Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 V Internal Power Dissipation Plastic DIP (N) . . . . . . . . . . . . . . Observe Derating Curves Cerdip (Q) . . . . . . . . . . . . . . . . . . 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) . . . . . . . . . -65C to +125C Storage Temperature Range (Q) . . . . . . . . . -65C to +150C Storage Temperature Range (R) . . . . . . . . . -65C to +150C Operating Temperature Range AD822A/B . . . . . . . . . . . . . . . . . . . . . . . . . -40C to +85C AD822S . . . . . . . . . . . . . . . . . . . . . . . . . . -55C to +125C Lead Temperature Range (Soldering 60 sec) . . . . . . . +260C NOTES 1 Stresses above those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. This is a stress rating only and 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-Pin Plastic DIP Package: JA = 90C/Watt 8-Pin Cerdip Package: JA = 110C/Watt 8-Pin SOIC Package: JA = 160C/Watt 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 145C. For the cerdip packages, the maximum junction temperature is 175C. If these maximums are exceeded momentarily, proper circuit WARNING! ESD SENSITIVE DEVICE 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 Figure 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 volts (or less) at an ambient temperature of +25C 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 Temperature Package Package Model1 Range Description Option AD822AN -40C to +85C N-8 AD822BN -40C to +85C AD822AR AD822BR AD822AR-3V AD822AN-3V -40C to +85C -40C to +85C -40C to +85C -40C to +85C AD822A Chips Standard Military Drawing2 -40C to +85C 8-Pin Plastic Mini-DIP 8-Pin Plastic Mini-DIP 8-Pin SOIC 8-Pin SOIC 8-Pin SOIC 8-Pin Plastic Mini-DIP Die -55C to +125C 8-Pin Cerdip Q-8 N-8 R-8 R-8 R-8 N-8 NOTES 1 Spice model is available on ADI Model Disc. 2 Contact factory for availability. METALIZATION PHOTOGRAPH Contact factory for latest dimensions. Dimensions shown in inches and (mm). -6- REV. A Typical Characteristics-AD822 5 70 VS = 0V, 5V INPUT BIAS CURRENT - pA 60 NUMBER OF UNITS 50 40 30 20 0 VS = 0V, +5V AND 5V VS = 5V 10 0 -0.5 -5 -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 OFFSET VOLTAGE - mV 0.3 0.4 -5 0.5 -3 -2 -1 0 1 2 COMMON-MODE VOLTAGE - V 3 4 5 Figure 4. Input Bias Current vs. Common-Mode Voltage; VS = +5 V, 0 V and VS = 5 V Figure 1. Typical Distribution of Offset Voltage (390 Units) 1k 16 VS = 5V VS = 15V INPUT BIAS CURRENT - pA 14 12 10 % IN BIN -4 8 6 4 100 10 1 2 0 -12 -10 -8 -6 -4 -2 0 2 4 6 8 0.1 -16 10 -12 -8 OFFSET VOLTAGE DRIFT - V/C -4 0 4 8 12 16 COMMON-MODE VOLTAGE - V Figure 5. Input Bias Current vs. Common-Mode Voltage; VS = 15 V Figure 2. Typical Distribution of Offset Voltage Drift (100 Units) 100k 50 45 10k INPUT BIAS CURRENT - pA NUMBER OF UNITS 40 35 30 25 20 15 10 1k 100 10 1 5 0.1 0 0 1 2 3 4 5 6 7 INPUT BIAS CURRENT - pA 8 9 10 20 Figure 3. Typical Distribution of Input Bias Current (213 Units) REV. A 40 60 80 100 TEMPERATURE - C 120 140 Figure 6. Input Bias Current vs. Temperature; VS = 5 V, VCM = 0 -7- AD822-Typical Characteristics 10M 40 VS = 15V 1M INPUT VOLTAGE - V OPEN-LOOP GAIN - V/V POS RAIL V S = 0V, 5V VS = 0V, 3V 100k RL = 2k 20 RL = 20k NEG RAIL 0 POS RAIL POS RAIL -20 NEG RAIL RL = 100k 10k 100 1k 10k 100k 60 0 LOAD RESISTANCE - 120 180 240 300 OUTPUT VOLTAGE FROM SUPPLY RAILS - mV Figure 7. Open-Loop Gain vs. Load Resistance Figure 10. Input Error Voltage with Output Voltage within 300 mV of Either Supply Rail for Various Resistive Loads; VS = 5 V 1k INPUT VOLTAGE NOISE - nV/Hz 10M OPEN-LOOP GAIN - V/V NEG RAIL -40 V S = 15V RL = 100k 1M 100 V S = 0V, 5V V S = 15V RL = 10k VS = 0V, 5V 100k V S = 15V RL = 600 10 V S = 0V, 5V 10k -60 1 -40 -20 0 20 40 60 80 TEMPERATURE - C 100 120 100 FREQUENCY - Hz 1k 10k Figure 8. Open-Loop Gain vs. Temperature Figure 11. Input Voltage Noise vs. Frequency 300 -40 RL = 10k ACL = -1 -50 200 -60 100 R L = 10k RL = 100k THD - dB INPUT VOLTAGE - V 10 1 140 0 VS = 0V, 3V; V OUT = 2.5Vp-p -70 -80 VS = 15V; V OUT = 20Vp-p -90 VS = 5V; V OUT = 9V p-p -100 -200 R L = 600 -100 VS = 0V, 5V; V OUT = 4.5V p-p -300 -16 -12 -8 -4 0 4 OUTPUT VOLTAGE - V 8 12 -110 100 16 1k 10k FREQUENCY - Hz 100k Figure 12. Total Harmonic Distortion vs. Frequency Figure 9. Input Error Voltage vs. Output Voltage for Resistive Loads -8- REV. A AD822 100 100 80 80 90 60 60 GAIN 40 40 20 20 RL = 2k CL = 100pF 0 0 70 100 1k 10k 100k FREQUENCY - Hz 1M 40 30 20 0 10 COMMON-MODE ERROR VOLTAGE - mV OUTPUT IMPEDANCE - 10k 100k 1M 10M 5 ACL = +1 VS = 15V 1 0.1 0.01 1k 10k 100k FREQUENCY - Hz 1M 4 3 NEGATIVE RAIL 2 +25 C -55 C 1 +125 C POSITIVE RAIL +125 C -55 C 0 10M -1 0 1 2 3 COMMON-MODE VOLTAGE FROM SUPPLY RAILS - Volts Figure 14. Output Impedance vs. Frequency Figure 17. Absolute Common-Mode Error vs. CommonMode Voltage from Supply Rails (VS - VCM) +16 OUTPUT SATURATION VOLTAGE - mV 1000 +12 OUTPUT SWING FROM 0 TO Volts 1k Figure 16. Common-Mode Rejection vs. Frequency 10 1% +8 +4 0.1% 0 0.01% ERROR -4 -8 1% -12 -16 0.0 1.0 2.0 3.0 SETTLING TIME - s 4.0 100 V S - V OH V OL - V S 10 0 0.001 5.0 Figure 15. Output Swing and Error vs. Settling Time REV. A 100 FREQUENCY - Hz 1k 100 VS = 0V, 5V 50 -20 10M Figure 13. Open-Loop Gain and Phase Margin vs. Frequency 100 VS = 15V VS = 0V, 3V 60 10 -20 10 PHASE MARGIN IN DEGREES OPEN-LOOP GAIN - dB PHASE COMMON-MODE REJECTION - dB 80 0.01 0.1 1 LOAD CURRENT - mA 10 100 Figure 18. Output Saturation Voltage vs. Load Current -9- AD822-Typical Characteristics 100 90 ISOURCE = 10mA POWER SUPPLY REJECTION - dB OUTPUT SATURATION VOLTAGE - mV 1000 ISINK = 10mA 100 ISOURCE = 1mA ISINK = 1mA 10 ISOURCE = 10A ISINK = 10A 80 70 60 +PSRR 50 40 30 -PSRR 20 10 1 -60 0 -40 -20 0 20 40 60 80 100 120 140 10 100 1k TEMPERATURE - C Figure 19. Output Saturation Voltage vs. Temperature 1M 10M Figure 22. Power Supply Rejection vs. Frequency 80 30 RL = 2k 70 25 VS = 15V VS = 15V 60 50 OUTPUT VOLTAGE - V SHORT CIRCUIT CURRENT LIMIT - mA 10k 100k FREQUENCY - Hz -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 -20 -40 0 20 40 60 80 TEMPERATURE - C 100 120 0 10k 140 Figure 20. Short Circuit Current Limit vs. Temperature 1600 2.4 (PLASTIC) T JMAX = 145 C (HERMETIC) T JMAX = 175 C TOTAL POWER DISSIPATION - Watts 2.2 T = +25 C 1200 T = -55 C 1000 800 600 400 200 2.0 1.8 1.6 1.4 8-PIN MINI-DIP (PLASTIC) 1.0 0.8 0.4 -60 0 4 8 12 16 20 24 28 30 36 8-PIN SOIC (PLASTIC) -40 -20 0 20 40 60 80 100 120 140 AMBIENT TEMPERATURE - C TOTAL SUPPLY VOLTAGE - Volts Figure 21. Quiescent Current vs. Supply Voltage vs. Temperature 8-PIN CERDIP (HERMETIC) 1.2 0.6 0 10M Figure 23. Large Signal Frequency Response T = +125 C 1400 QUIESCENT CURRENT - A 100k 1M FREQUENCY - Hz Figure 24. Maximum Power Dissipation vs. Temperature for Plastic and Hermetic Packages -10- REV. A AD822 VOUT -70 20k +VS 2.2k -80 0.1F 2 CROSSTALK - dB -90 20V p-p 3 -100 1F 6 8 1/2 AD822 1 7 5k 1/2 AD822 5 5k VIN -110 CROSSTALK = 20 LOG -120 VOUT 10V IN 0.1F 1F -VS -130 Figure 28. Crosstalk Test Circuit -140 300 1k 3k 10k 30k FREQUENCY - Hz 100k 300k 1M Figure 25. Crosstalk vs. Frequency 5V 5s 100 90 +VS 0.01F 8 1/2 AD822 VIN 4 0.01F RL 100pF VOUT 10 -V S 0% Figure 26. Unity-Gain Follower 5V Figure 29. Large Signal Response Unity Gain Follower; VS = 15 V, RL = 10 k 10s 10mV 100 100 90 90 10 10 0% 0% Figure 27. 20 V p-p, 25 kHz Sine Wave Input; Unity Gain Follower; RL = 600 , VS = 15 V REV. A 500ns Figure 30. Small Signal Response Unity Gain Follower; VS = 15 V, RL = 10 k -11- AD822 1V 2s 1V 100 100 90 90 10 GND 2s 10 0% GND 0% Figure 31. VS = +5 V, 0 V; Unity Gain Follower Response to 0 V to 4 V Step Figure 34. VS = +5 V, 0 V; Unity Gain Follower Response to 0 V to 5 V Step 10mV 2s 100 +VS 90 0.01F 8 VIN 1/2 AD822 RL 4 100pF VOUT 10 GND 0% Figure 35. VS = +5 V, 0 V; Unity Gain Follower Response, to 40 mV Step Centered 40 mV Above Ground, RL = 10 k Figure 32. Unity Gain Follower 10mV 10k 20k 2s 100 VIN 90 VOUT +VS 0.01F 8 1/2 AD822 4 RL 100pF 10 GND Figure 33. Gain of Two Inverter 0% Figure 36. VS = +5 V, 0 V; Gain of Two Inverter Response to 20 mV Step, Centered 20 mV Below Ground, RL = 10 k -12- REV. A AD822 1V 2s 1V 2s 100 90 100 90 10 GND 0% 1V 10 GND 0% a 1V 1V 10s 100 +VS 90 GND 0% Figure 37. VS = +5 V, 0 V; Gain of Two Inverter Response to 2.5 V Step Centered -1.25 V Below Ground, RL = 10 k 10 1V 500mV 10s b. 100 +5V 90 RP V IN VOUT 10 GND 0% Figure 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 k Figure 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 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 common-mode 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 Figures 31 and 34) and increased common-mode voltage error as illustrated in Figure 17. The AD822 does not exhibit phase reversal for input voltages up to and including +VS. Figure 39a shows the response of an AD822 voltage follower to a 0 V to +5 V (+VS) square wave input. The input and output arc 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 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 Figure 39b. REV. A 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 Figure 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 k resistor allows the amplifier to withstand up to 10 volts of continuous overvoltage, and increases the input voltage noise by a negligible amount. Input voltages less than -VS are a completely different story. The amplifier can safely withstand input voltages 20 volts below the minus supply voltage as long as the total voltage from the positive supply to the input terminal is less than 36 volts. In addition, the input stage typically maintains picoamp level input currents across that input voltage range. -13- AD822 The AD822 is designed for 13 nV/Hz wideband input voltage noise and maintains low noise performance to low frequencies (refer to Figure 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 k and signal bandwidths greater than 1 kHz. This is illustrated in Figure 40. 20mV 90 10 0% WHENEVER JOHNSON NOISE IS GREATER THAN AMPLIFIER NOISE, AMPLIFIER NOISE CAN BE CONSIDERED NEGLIGIBLE FOR APPLICATION. 1kHz Figure 41. Small Signal Response of AD822 as Unity Gain Follower Driving 350 pF Capacitive Load 1k RESISTOR JOHNSON NOISE 100 5 10 10Hz 4 RF NOISE GAIN - 1+ --- RI INPUT VOLTAGE NOISE - VRMS 100k 10k 2 s 100 1 AMPLIFIER GENERATED NOISE 0.1 10k 100k 1M 10M 100M SOURCE IMPEDANCE - 1G 3 10G Figure 40. Total Noise vs. Source Impedance 2 OUTPUT CHARACTERISTICS 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 sourcing and 20 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. The amplifier's open-loop gain characteristic will change as a function of resistive load, as shown in Figures 7 through 10. For load resistances over 20 k, the AD822's input error voltage is virtually unchanged until the output voltage is driven to 180 mV of either supply. If the AD822's output is overdriven so as to saturate either of the output devices, the amplifier will recover within 2 s of its input returning to the amplifier's linear operating region. 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 41 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. Figure 42 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. 1 300 1k 3k 10k CAPACITIVE LOAD FOR 20 PHASE MARGIN - pF 30k RF CL RI Figure 42. Capacitive Load Tolerance vs. Noise Gain Figure 43 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. +VS 0.01F 8 VIN 100 1/2 AD822 VOUT 0.01F 4 CL -VS 20pF 20k Figure 43. Extending Unity Gain Follower Capacitive Load Capability Beyond 350 pF -14- REV. A AD822 APPLICATIONS Single Supply Voltage-to-Frequency Converter Table I. AD822 In Amp Performance The circuit shown in Figure 44 uses the AD822 to drive a low power timer, which 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, which 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 U4 REF-02 2 6 VREF = 5V C5 0.1F 3 5 CMOS 74HCO4 RSCALE ** 10k 4 OUT2 U3B 4 3 U3A 2 R1 VIN U1 C1 VS = 65 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 s R3 * 116k 5 s 270 nV/Hz 2.2 V/Hz 1.15 mA 270 nV/Hz 2.2 V/Hz 1.10 mA 1 OUT1 5s U2 CMOS 555 4 6 2 1/2 AD822B 7 499k, 1% 0V TO 2.5V FULL SCALE C2 0.01F, 2% VS = 3 V, 0 V C3 0.1F 0.01F, 2% R2 499k, 1% Parameters C6 390pF 5% (NPO) 100 8 V+ R THR OUT TR DIS GND CV 90 3 5 1 C4 0.01F 10 0% NOTES: 1V fOUT = V IN /(VREF*t 1 ), t 1 = 1.1*R3*C6 = 25kHz f S AS SHOWN. * = 1% METAL FILM, <50ppm/ C TC Figure 45a. Pulse Response of In Amp to a 500 mV p-p Input Signal; VS = +5 V, 0 V; Gain = 10 ** = 10%, 20T FILM, <100ppm/ C TC t1 = 33s FOR fOUT = 20kHz @ V IN = 2.0V Figure 44. Single Supply Voltage-to-Frequency Converter VREF Typical AD822 bias currents of 2 pA allow megaohm-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 volt single supply which delivers less than 1 mA to the entire circuit. R1 R2 R3 R4 R5 R6 90k 9k 1k 1k 9k 90k G =10 G =100 G =100 OHMTEK PART # 1043 G =10 +V S 0.1F Single Supply Programmable Gain Instrumentation Amplifier 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. 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. REV. A 6 2 VIN1 1/2 8 3 AD822 RP 1k 1 1/2 7 5 AD822 4 RP VOUT VIN2 1k (G =10) V OUT = (VIN1 -V IN2 ) (1+ R6 ) +VREF R4 + R5 (G =100) VOUT = (V IN1 -V IN2 ) (1+ R5 + R6 ) +VREF R4 FOR R1 = R6, R2 = R5, AND R3 = R4 Figure 45b. A Single Supply Programmable Instrumentation Amplifier -15- AD822 0.1F 95.3k 1F 8 1/2 AD822 3 CHANNEL 1 MYLAR 47.5k The AD822 can be used for driving a 350 ohm Wheatstone bridge. Figure 47 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: 0.1F 1 500F 2 L 4.99k 95.3k 10k HEADPHONES 32 IMPEDANCE 10k R 4.99k G= 6 47.5k 1F CHANNEL 2 1/2 AD822 5 4 7 500F MYLAR C1821a-10-9/94 Low Dropout Bipolar Bridge Driver +3V 49.4 k +1 RG +VS 49.9k Figure 46. 3 Volt Single Supply Stereo Headphone Driver +1.235V 3 Volt, Single Supply Stereo Headphone 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 which consume more power and cannot run on 3 V power supplies. 3 AD589 8 1/2 AD822 R1 20 TO A/D CONVERTER REFERENCE INPUT 1 2 26.4k, 1% 10k 1% 350 +VS 350 7 3 350 350 AD620 RG 2 In Figure 46, each channel s input signal is coupled via a 1 F 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 F capacitors and the headphones, which can be modeled as 32 ohm load resistors to ground. This ensures that all signals in the audio frequency range (20 Hz-20 kHz) are delivered to the headphones. 6 5 4 10k VREF -VS 1% 10k 6 1% 5 1/2 AD822 4 7 +VS -4.5V R2 20 +5V 0.1F GND 1F 0.1F -VS 1F +VS -5V Figure 47. Low Dropout Bipolar Bridge Driver OUTLINE DIMENSIONS Dimensions shown in inches and (mm). Mini-DIP (N) Package Cerdip (Q) Package 0.005 (0.13) MIN 8 SOIC (R) Package 0.150 (3.81) 0.055 (1.35) MAX 5 1 8 5 0.31 (7.87) 1 4 0.0350.01 (0.890.25) 0.180.03 (4.570.76) 0.125 (3.18) MIN 0.0180.003 (0.460.08) 0.033 (0.84) NOM SEATING PLANE 4 1 0.197 (5.01) 0.189 (4.80) 0.060 (1.52) 0.015 (0.38) 0.150 (3.81) MIN 0.023 (0.58) 0.014 (0.36) 0.30 (7.62) REF 0.100 (2.54) BSC 0.320 (8.13) 0.290 (7.37) 0.0110.003 (0.280.08) 15 0 PIN 1 0.157 (3.99) 0.150 (3.81) 0.405 (10.29) MAX 0.200 (5.08) MAX 0.200 (5.08) 0.125 (3.18) 0.10 (2.54) BSC 5 0.244 (6.20) 0.228 (5.79) 0.070 (1.78) 0.030 (0.76) 0.39 (9.91) MAX 0.1650.01 (4.190.25) 8 0.310 (7.87) 0.220 (5.59) 4 0.015 (0.38) 0.008 (0.20) 0.102 (2.59) 0.094 (2.39) 0.010 (0.25) 0.004 (0.10) 0.050 (1.27) BSC SEATING PLANE 0.019 (0.48) 0.014 (0.36) 0.020 (0.051) x 45 CHAMF 0.190 (4.82) 0.170 (4.32) 8 0 0.090 (2.29) 10 0 0.098 (0.2482) 0.075 (0.1905) 0.030 (0.76) 0.018 (0.46) 0-15 -16- REV. A PRINTED IN U.S.A. 0.25 (6.35) PIN 1