1 nV/Hz Low Noise Instrumentation Amplifier Data Sheet AD8429 FEATURES PIN CONNECTION DIAGRAM Low noise AD8429 IN 1 8 +V S 1 nV/Hz input noise R 2 7 V G OUT 45 nV/Hz output noise R 3 6 REF G High accuracy dc performance (AD8429BRZ) +IN 4 5 V S 90 dB CMRR minimum (G = 1) 50 V maximum input offset voltage TOP VIEW (Not to Scale) 0.02% maximum gain accuracy (G = 1) Figure 1. Excellent ac specifications 80 dB CMRR to 5 kHz (G = 1) 15 MHz bandwidth (G = 1) 1.2 MHz bandwidth (G = 100) 22 V/s slew rate THD: 130 dBc (1 kHz, G = 1) Versatile 4 V to 18 V dual supply Gain set with a single resistor (G = 1 to 10,000) Temperature range for specified performance 40C to +125C APPLICATIONS Medical instrumentation Precision data acquisition Microphone preamplification Vibration analysis GENERAL DESCRIPTION The AD8429 is an ultralow noise, instrumentation amplifier be useful to shift the output level when interfacing to a single designed for measuring extremely small signals over a wide supply signal chain. temperature range (40C to +125C). The AD8429 performance is specified over the extended industrial The AD8429 excels at measuring tiny signals. It delivers ultralow temperature range of 40C to +125C. It is available in an 8-lead input noise performance of 1 nV/Hz. The high CMRR of the plastic SOIC package. 1000 AD8429 prevents unwanted signals from corrupting the acqui- sition. The CMRR increases as the gain increases, offering high rejection when it is most needed. The high performance pin 100 configuration of the AD8429 allows it to reliably maintain high G = 1 CMRR at frequencies well beyond those of typical instrumentation amplifiers. 10 The AD8429 reliably amplifies fast changing signals. Its current G = 10 feedback architecture provides high bandwidth at high gain, for G = 100 example, 1.2 MHz at G = 100. The design includes circuitry to im- 1 G = 1k prove settling time after large input voltage transients. The AD8429 was designed for excellent distortion performance, allowing use in demanding applications such as vibration analysis. 0.1 1 10 100 1k 10k 100k Gain is set from 1 to 10,000 with a single resistor. A reference FREQUENCY (Hz) pin allows the user to offset the output voltage. This feature can Figure 2. RTI Voltage Noise Spectral Density vs. Frequency Rev. A Document Feedback 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 One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. rights of third parties that may result from its use. Specifications subject to change without notice. No Tel: 781.329.4700 20112017 Analog Devices, Inc. All rights reserved. license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Technical Support www.analog.com Trademarks and registered trademarks are the property of their respective owners. NOISE (nV/Hz) 09730-001 09730-002AD8429 Data Sheet TABLE OF CONTENTS Features .............................................................................................. 1 Architecture ................................................................................ 15 Applications ....................................................................................... 1 Gain Selection ............................................................................. 15 Pin Connection Diagram ................................................................ 1 Reference Terminal .................................................................... 15 General Description ......................................................................... 1 Input Voltage Range ................................................................... 16 Revision History ............................................................................... 2 Layout .......................................................................................... 16 Specifications ..................................................................................... 3 Input Bias Current Return Path ............................................... 17 Absolute Maximum Ratings ............................................................ 6 Input Protection ......................................................................... 17 Thermal Resistance ...................................................................... 6 Radio Frequency Interference (RFI) ........................................ 17 ESD Caution .................................................................................. 6 Calculating the Noise of the Input Stage ................................. 18 Pin Configuration and Function Descriptions ............................. 7 Outline Dimensions ....................................................................... 19 Typical Performance Characteristics ............................................. 8 Ordering Guide .......................................................................... 19 Theory of Operation ...................................................................... 15 REVISION HISTORY 2/2017Rev, 0 to Rev. A Changes to Figure 2 .......................................................................... 1 Change to Input Current Parameter, Table 1 ................................ 3 Changes to Figure 20 and Figure 21 ............................................. 10 Changes to Figure 24 through Figure 27 ..................................... 11 Changes to Figure 28 and Figure 30 ............................................. 12 Change to Large Differential Input Voltage at High Gain Section .............................................................................................. 17 Changes to Figure 53 ...................................................................... 18 4/2011Revision 0: Initial Version Rev. A Page 2 of 20