AD795 Analog Devices, AD795 Datasheet
AD795
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AD795 Summary of contents
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... Furthermore, the AD795 features a guaranteed low input noise of 3.3 μV p-p (0 Hz) and a 11 nV/√Hz maximum noise level at 10 kHz. The AD795 has a fully specified and tested input offset voltage drift of only 10 μV/°C maximum. The AD795 is useful for many high input impedance, low noise applications. The AD795 is rated over the commercial tempera- ture range of 0° ...
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... AD795 TABLE OF CONTENTS Features .............................................................................................. 1 Applications ....................................................................................... 1 Connection Diagram ....................................................................... 1 General Description ......................................................................... 1 Revision History ............................................................................... 2 Specifications ..................................................................................... 3 Absolute Maximum Ratings ............................................................ 5 Thermal Resistance ...................................................................... 5 ESD Caution .................................................................................. 5 Typical Performance Characteristics ............................................. 6 Minimizing Input Current ............................................................ 11 Circuit Board Notes ........................................................................ 12 REVISION HISTORY 12/09—Rev Rev. C Changes to Features Section and General Description Section . 1 Changes to Input Bias Current Parameter, Table 1 ...................... 3 Changes to Table 2 ...
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... MIN MAX R ≥ 2 kΩ V − − − 4 MIN MAX ±10 V ±5 OUT Short circuit Rev Page AD795 AD795JR Typ Max Unit 100 500 μV 300 1000 μ μV/°C 110 dB 100 ...
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... Defined as the maximum continuous voltage between the inputs such that neither input exceeds ±10 V from ground. Test Conditions/Comments Min ±4 = +25° +25°C. For higher temperature, the current doubles every 10°C. A Rev Page AD795JR Typ Max Unit ±15 V ±18 V 1.3 1.5 mA ...
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... −65°C to +125°C soldered on a 4-layer circuit board for surface-mount packages. Table 3. Thermal Resistance 0°C to +70°C Package Type 8-Lead SOIC ESD CAUTION Rev Page AD795 θ Unit JA 155 °C/W ...
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... AD795 TYPICAL PERFORMANCE CHARACTERISTICS 10kΩ – SUPPLY VOLTAGE (±V) Figure 4. Common-Mode Voltage Range vs. Supply Voltage 10kΩ OUT 10 –V OUT SUPPLY VOLTAGE (±V) Figure 5. Output Voltage Range vs. Supply Voltage ±15V ...
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... Rev Page NOISE BANDWIDTH: 0.1Hz TO 10Hz k 10 100k 1M 10M 100M SOURCE RESISTANCE (Ω) Figure 13. Input Voltage Noise vs. Source Resistance SAMPLE SIZE = 344 f = 0.1Hz TO 10Hz 1 2 INPUT VOLTAGE NOISE (µV p-p) 10 100 1k 10k 100k 1M FREQUENCY (Hz) Figure 15. Input Voltage Noise Spectral Density AD795 1G 3 10M ...
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... AD795 30 25 –OUTPUT CURRENT 20 +OUTPUT CURRENT –60 –40 – TEMPERATURE (°C) Figure 16. Short-Circuit Current Limit vs. Temperature 0.1% 4 0.01 ERROR –2 0.01% –4 0.1% –6 –8 – SETTLING TIME (µs) Figure 17. Output Swing and Error vs. Settling Time 1000 ...
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... Figure 26. Typical Distribution of Input Offset Voltage V IN 100k Rev Page SUPPLY VOLTAGE (±V) 0 100 200 300 400 INPUT OFFSET VOLTAGE (µV) 10kΩ 0.1µF 10kΩ AD795 6 OUT 10kΩ 100pF 4 0.1µF –V S Figure 27. Unity Gain Inverter AD795 20 500 ...
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... Figure 28. Unity Gain Inverter Large Signal Pulse Response 10mV 100 Figure 29. Unity Gain Inverter Small Signal Pulse Response +V S 0.1µ AD795 10kΩ 4 0.1µF –V S Figure 30. Unity Gain Follower 5µs 100 Figure 31. Unity Gain Follower Large Signal Pulse Response ...
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... MINIMIZING INPUT CURRENT The AD795 is guaranteed maximum input current with ±15 V supply voltage at room temperature. Careful atten- tion to how the amplifier is used is necessary to maintain this performance. The amplifier’s operating temperature should be kept as low as possible. Like other JFET input amplifiers, the AD795’s input current doubles for every 10° ...
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... Voltage differences between the input pins and other pins as well as PCB metal traces causes parasitic currents (see Figure 33) larger than the AD795’s input current unless special precautions are taken. Two methods of minimizing parasitic leakages include guarding of the input lines and maintaining adequate insulation resistance ...
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... One option that eliminates all effects of board resistance is shown in Figure 36. The AD795’s sensitive input pin (either Pin 2 when connected as an inverter, or Pin 3 when connected as a follower) is bent up and soldered directly to a Teflon® insulated standoff. Both the ...
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... AC RESPONSE WITH HIGH VALUE SOURCE AND FEEDBACK RESISTANCE Source and feedback resistances greater than 100 kΩ magnifies the effect of input capacitances (stray and inherent to the AD795) on the ac behavior of the circuit. The effects of common-mode and differential input capacitances should be taken into account because the circuit’s bandwidth and stability can be adversely affected ...
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... IN Figure schematic of the AD795 as an inverter with an input voltage clamp. Bootstrapping the clamp diodes at the inverting input minimizes the voltage across the clamps and keeps the leakage due to the diodes low. Low leakage diodes ...
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... A shunt resistance on the order of 10 Ω is typical for a small photodiode. Resistance junction resistance, which typically drops by a factor of two for every 10°C rise in temperature. In the AD795, both the offset voltage and drift are low, which helps minimize these errors 10pF 1GΩ ...
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... A T network, shown in Figure 49, can be used to boost the effective transimpedance of an I-to-V converter, for a given feedback resistor value. However, amplifier noise and offset voltage contributions are also amplified by the T network gain. A low noise, low offset voltage amplifier, such as the AD795, is needed for this type of application. 10pF R F 100MΩ ...
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... COPLANARITY ORDERING GUIDE 1 Model Temperature Range AD795JR 0°C to +70°C AD795JR-REEL 0°C to +70°C AD795JR-REEL7 0°C to +70°C AD795JRZ 0°C to +70°C AD795JRZ-REEL 0°C to +70°C AD795JRZ-REEL7 0°C to +70° RoHS Compliant Part. 5.00 (0.1968) 4.80 (0.1890 6.20 (0.2441) 4.00 (0.1574) 1 5.80 (0.2284) 3 ...
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... NOTES Rev Page AD795 ...
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... AD795 NOTES ©2002–2009 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. D00845-0-12/09(C) Rev Page ...