Datasheet AD795 (Analog Devices)

Low Power, Low Noise Precision FET Op Amp AD795 FEATURES CONNECTION DIAGRAM Low power replacement for Burr-Brown NC 1 8 NC OPA111, OPA121 op amps –IN 2 7 +VS Low noise +IN 3 6 OUTPUT 3.3 μV p-p maximum, 0.1 Hz to 10 Hz –VS 4 5 NC AD795
1
11 nV/√Hz maximum at 10 kHz
-00 5 84
0.6 fA/√Hz at 1 kHz NC = NO CONNECT
00
High dc accuracy
Figure 1. 8-Lead SOIC (R) Package
500 μV maximum offset voltage 10 μV/°C maximum drift 2 pA maximum input bias current Low power: 1.5 mA maximum supply current APPLICATIONS Low noise photodiode preamps CT scanners Precision l-to-V converters GENERAL DESCRIPTION
The AD795 is a low noise, precision, FET input operational Furthermore, the AD795 features a guaranteed low input noise amplifier. It offers both the low voltage noise and low offset drift of 3.3 μV p-p (0.1 Hz to 10 Hz) and a 11 nV/√Hz maximum of a bipolar input op amp and the very low bias current of a FET- noise level at 10 kHz. The AD795 has a fully specified and input device. The 1014 Ω common-mode impedance insures tested input offset voltage drift of only 10 μV/°C maximum. that input bias current is essentially independent of common- The AD795 is useful for many high input impedance, low noise mode voltage and supply voltage variations. applications. The AD795 is rated over the commercial tempera- The AD795 has both excellent dc performance and a guaranteed ture range of 0°C to +70°C. and tested maximum input voltage noise. It features 2 pA The AD795 is available in an 8-lead SOIC package. maximum input bias current and 500 μV maximum offset
50
voltage, along with low supply current of 1.5 mA maximum.
SAMPLE SIZE = 570 1k ) Hz 40 / V S T (n Y IT UNI S F 30 N O 100 E DE G A RAL NT 20 CT E RCE P E S P E 10 10 IS NO E G A T 0 L –5 –4 –3 –2 –1 0 1 2 3 4 5
030
O
5-
V INPUT OFFSET VOLTAGE DRIFT (µV/°C)
84
1
00 2
10 100 1k 10k
005- Figure 3. Typical Distribution of Average Input Offset Voltage Drift
FREQUENCY (Hz)
84 00 Figure 2. Voltage Noise Spectral Density
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Document Outline Features Applications Connection Diagram General Description Revision History Specifications Absolute Maximum Ratings Thermal Resistance ESD Caution Typical Performance Characteristics Minimizing Input Current Circuit Board Notes Offset Nulling AC Response with High Value Source and Feedback Resistance Overload Issues Input Protection Preamplifier Applications Minimizing Noise Contributions Using a T Network A pH Probe Buffer Amplifier Outline Dimensions Ordering Guide