AD549 AD | Alldatasheet
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GUARD PIN, CONNECTED TO CASE INVERTING INPUT VOS TRIM –15V 10kΩ NC = NO CONNECTION 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. a Ultralow Input Bias Current Operational Amplifier AD549* Tel: 617/329-4700 Fax: 617/326-8703
FEATURES
Ultralow Bias Current: 60 fA max (AD549L) 250 fA max (AD549J) Input Bias Current Guaranteed Over Common-Mode Voltage Range Low Offset Voltage: 0.25 mV max (AD549K) 1.00 mV max (AD549J) Low Offset Drift: 5 mV/8C max (AD549K) 20 mV/8C max (AD549J) Low Power: 700 mA max Supply Current Low Input Voltage Noise: 4 mV p-p 0.1 Hz to 10 Hz MIL-STD-883B Parts Available
APPLICATIONS
Vacuum lon Gage Measurement PRODUCT DESCRIPTION The AD549 is a monolithic electrometer operational amplifier with very low input bias current. Input offset voltage and input offset voltage drift are laser trimmed for precision performance. The AD549’s ultralow input current is achieved with “Topgate” JFET technology, a process development exclusive to Analog Devices. This technology allows the fabrication of extremely low input current JFETs compatible with a standard junction- isolated bipolar process. The 10 15 Ω common-mode impedance, a result of the bootstrapped input stage, insures that the input current is essentially independent of common-mode voltage. The AD549 is suited for applications requiring very low input current and low input offset voltage. It excels as a preamp for a wide variety of current output transducers such as photodiodes, photomultiplier tubes, or oxygen sensors. The AD549 can also be used as a precision integrator or low droop sample and hold. The AD549 is pin compatible with standard FET and electrom- eter op amps, allowing designers to upgrade the performance of present systems at little additional cost. The AD549 is available in a TO-99 hermetic package. The case is connected to Pin 8 so that the metal case can be independently connected to a point at the same potential as the input termi- nals, minimizing stray leakage to the case. *Protected by Patent No. 4,639,683. The AD549 is available in four performance grades. The J, K, and L versions are rated over the commercial temperature range 0°C to +70°C. The S grade is specified over the military tem- perature range of –55°C to +125°C and is available processed to MIL-STD-883B, Rev C. Extended reliability PLUS screening is also available. Plus screening includes 168-hour burn-in, as well as other environmental and physical tests derived from MIL-STD-883B, Rev C. PRODUCT HIGHLIGHTS 1. The AD549’s input currents are specified, 100% tested and guaranteed after the device is warmed up. Input current is guaranteed over the entire common-mode input voltage range. 2. The AD549’s input offset voltage and drift are laser trimmed to 0.25 mV and 5 µV/°C (AD549K), 1 mV and 20 µV/°C (AD549J). 3. A maximum quiescent supply current of 700 µA minimizes heating effects on input current and offset voltage. 4. AC specifications include 1 MHz unity gain bandwidth and 3 V/µs slew rate. Settling time for a 10 V input step is 5 µs to 0.01%. 5. The AD549 is an improved replacement for the AD515, OPA104, and 3528.
AD549–SPECIFICATIONS Model AD549J AD549K AD549L AD549S Min Typ Max Min Typ Max Min Typ Max Min Typ Max Units INPUT BIAS CURRENT 1 Either Input, V CM = 0 V 150 250 75 100 40 60 75 100 fA Either Input, V CM = ± 10 V 150 250 75 100 40 60 75 100 fA Either Input at T MAX, VCM = 0 V 11 4.2 2.8 420 pA Offset Current 50 30 20 30 fA Offset Current at T MAX 2.2 1.3 0.85 125 pA INPUT OFFSET VOLTAGE 2 Offset at TMAX 1.9 0.4 0.9 2.0 mV vs. Temperature 10 20 2 5 5 10 10 15 µV/°C vs. Supply 32 100 10 32 10 32 10 32 µV/V vs. Supply, T MIN to TMAX 32 100 10 32 10 32 32 50 µV/V Long-Term Offset Stability 15 15 15 15 µV/Month INPUT VOLTAGE NOISE f = 0.1 Hz to 10 Hz 4 4 6 44 µV p-p f = 10 Hz 90 90 90 90 nV/ √Hz f = 100 Hz 60 60 60 60 nV/ √Hz f = 1 kHz 35 35 35 35 nV/ √Hz f = 10 kHz 35 35 35 35 nV/ √Hz INPUT CURRENT NOISE f = 1 kHz 0.22 0.16 0.11 0.16 fA/ √Hz INPUT IMPEDANCE Differential VDIFF = ± 11 0 13i11 0 13i11 0 13i11 0 13i1 Ω ipF Common Mode VCM = ± 10 10 15i0.8 10 15i0.8 10 15i0.8 10 15i0.8 Ω ipF OPEN-LOOP GAIN VO @ ± 10 V, RL = 10 k 300 1000 300 1000 300 1000 300 1000 V/mV VO @ ± 10 V, RL = 10 k, TMIN to TMAX 300 800 300 800 300 800 300 800 V/mV VO = ± 10 V, RL = 2 k 100 250 100 250 100 250 100 250 V/mV VO = ± 10 V, RL = 2 k, TMIN to TMAX 80 200 80 200 80 200 25 150 V/mV INPUT VOLTAGE RANGE Differential 3 ± 20 ± 20 ± 20 ± 20 V Common-Mode Voltage –10 +10 –10 +10 –10 +10 –10 +10 V Common-Mode Rejection Ratio V = +10 V, –10 V 80 90 90 100 90 100 90 100 dB TMIN to TMAX 76 80 80 90 80 90 80 90 dB OUTPUT CHARACTERISTICS Voltage @ RL = 10 k, TMIN to TMAX –12 +12 –12 +12 –12 +12 –12 +12 V Voltage @ RL = 2 k, TMIN to TMAX –10 +10 –10 +10 –10 +10 –10 +10 V Short Circuit Current 15 20 35 15 20 35 15 20 35 15 20 35 mA TMIN to TMAX 9996 mA Load Capacitance Stability G = +1 4000 4000 4000 4000 pF FREQUENCY RESPONSE Full Power Response 50 50 50 50 kHz Slew Rate 2 3 2 3 2 3 2 3 V/ µs 0 . 0 1 % 5555 µs Overload Recovery, 50% Overdrive, G = –1 2222 µs (@ +258C and VS = +15 V dc, unless otherwise noted) REV. A–2–
Model AD549J AD549K AD549L AD549S Min Typ Max Min Typ Max Min Typ Max Min Typ Max Units POWER SUPPLY Rated Performance ± 15 ± 15 ± 15 ± 15 V Operating 65 618 65 618 65 618 65 618 V TEMPERATURE RANGE Operating, Rated Performance 0 +70 0 +70 0 +70 –55 +125 °C Storage –65 +150 –65 +150 –65 +150 –65 +150 °C PACKAGE OPTION TO-99 (H-08A) AD549JH AD549KH AD549LH AD549SH, AD549SH/883B Chips AD549JChips NOTES 1Bias current specifications are guaranteed after 5 minutes of operation at T A = +25°C. Bias current increases by a factor of 2.3 for every 10 °C rise in temperature. 2Input offset voltage specifications are guaranteed after 5 minutes of operation at T A = +25°C. 3Defined as max continuous voltage between the inputs such that neither input exceeds ± 10 V from ground. Specifications subject to change without notice. All min and max specifications are guaranteed. Specifications in boldface are tested on all production units at final electrical test. Results from those tests are used to calculate outgoing quality levels. METALIZATION PHOTOGRAPH Dimensions shown in inches and (mm). Contact factory for latest dimensions. ABSOLUTE MAXIMUM RATINGS 1 Operating Temperature Range NOTES 1Stresses 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. 2For supply voltages less than ± 18 V, the absolute maximum input voltage is equal to the supply voltage. AD549 REV. A –3– WARNING! ESD SENSITIVE DEVICE 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 AD549 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.
Figure 1. Input Voltage Range
400 AMPLIFIER QUIESCENT CURRENT – µA
Figure 4. Quiescent Current Figure 7. Open-Loop Gain vs. Figure 2. Output Voltage Figure 5. CMRR vs. Input Figure 8. Change in Offset Figure 3. Output Voltage Figure 6. Open-Loop Gain vs. Figure 9. Input Bias Current
C) will be equal to 10 V at 100 °C and decrease by 26.8 mV/ °C. Figure 47. Table Illustrating Temperature Compensation appreciable percentage of a pH unit. be trimmed) will be below 0.5 mV. Figure 46. Temperature Compensated pH Probe Amplifier Dimensions shown in inches and (mm).