Datasheet AD8421 (Analog Devices)
| Manufacturer | Analog Devices |
| Description | 3 nV /√Hz, Low Power Instrumentation Amplifier |
| Pages / Page | 29 / 1 — 3 nV/√Hz, Low Power. Instrumentation Amplifier. Data Sheet. AD8421. … |
| File Format / Size | PDF / 682 Kb |
| Document Language | English |
3 nV/√Hz, Low Power. Instrumentation Amplifier. Data Sheet. AD8421. FEATURES. PIN CONNECTION DIAGRAM. Low power. –IN
Text Version of Document
3 nV/√Hz, Low Power Instrumentation Amplifier Data Sheet AD8421 FEATURES PIN CONNECTION DIAGRAM Low power AD8421 –IN 1 8 +V 2.3 mA maximum supply current S Low noise RG 2 7 VOUT 3.2 nV/√Hz maximum input voltage noise at 1 kHz RG 3 6 REF 200 fA/√Hz current noise at 1 kHz +IN 4 5 –VS
1
Excellent ac specifications
00
TOP VIEW
123-
10 MHz bandwidth (G = 1) (Not to Scale)
10
2 MHz bandwidth (G = 100)
Figure 1.
0.6 μs settling time to 0.001% (G = 10) 80 dB CMRR at 20 kHz (G = 1) 35 V/μs slew rate High precision dc performance (AD8421BRZ) 94 dB CMRR minimum (G = 1) 10µ G = 100 0.2 μV/°C maximum input offset voltage drift 1 ppm/°C maximum gain drift (G = 1) /√Hz) BEST AVAILABLE V 7mA LOW NOISE IN-AMP 500 pA maximum input bias current z ( 1µ kH Inputs protected to 40 V from opposite supply 1 T ±2.5 V to ±18 V dual supply (5 V to 36 V single supply) A ITY Gain set with a single resistor (G = 1 to 10,000) S 100n N E D APPLICATIONS E IS BEST AVAILABLE O 1mA LOW POWER IN-AMP Medical instrumentation 10n L N Precision data acquisition AD8421 TOTA Microphone preamplification RS NOISE ONLY Vibration analysis 1n100 1k 10k 100k 1M
078
Multiplexed input applications
23-
SOURCE RESISTANCE, RS (Ω)
101
ADC driver
Figure 2. Noise Density vs. Source Resistance
GENERAL DESCRIPTION
The AD8421 is a low cost, low power, extremely low noise, ultralow The AD8421 delivers 3 nV/√Hz input voltage noise and bias current, high speed instrumentation amplifier that is ideally 200 fA/√Hz current noise with only 2 mA quiescent current, suited for a broad spectrum of signal conditioning and data making it an ideal choice for measuring low level signals. For acquisition applications. This product features extremely high applications with high source impedance, the AD8421 employs CMRR, allowing it to extract low level signals in the presence of innovative process technology and design techniques to provide high frequency common-mode noise over a wide temperature noise performance that is limited only by the sensor. range. The AD8421 uses unique protection methods to ensure robust The 10 MHz bandwidth, 35 V/μs slew rate, and 0.6 μs settling inputs while still maintaining very low noise. This protection time to 0.001% (G = 10) allow the AD8421 to amplify high speed allows input voltages up to 40 V from the opposite supply rail signals and excel in applications that require high channel count, without damage to the part. multiplexed systems. Even at higher gains, the current feedback A single resistor sets the gain from 1 to 10,000. The reference architecture maintains high performance; for example, at G = 100, pin can be used to apply a precise offset to the output voltage. the bandwidth is 2 MHz and the settling time is 0.8 μs. The AD8421 has excellent distortion performance, making it suitable The AD8421 is specified from −40°C to +85°C and has typical for use in demanding applications such as vibration analysis. performance curves to 125°C. It is available in 8-lead MSOP and SOIC packages.
Rev. 0 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 license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Tel: 781.329.4700 www.analog.com Trademarks and registered trademarks are the property of their respective owners. Fax: 781.461.3113 ©2012 Analog Devices, Inc. All rights reserved.
Document Outline FEATURES APPLICATIONS PIN CONNECTION DIAGRAM GENERAL DESCRIPTION TABLE OF CONTENTS REVISION HISTORY SPECIFICATIONS AR AND BR GRADES ARM AND BRM GRADES ABSOLUTE MAXIMUM RATINGS THERMAL RESISTANCE ESD CAUTION PIN CONFIGURATION AND FUNCTION DESCRIPTIONS TYPICAL PERFORMANCE CHARACTERISTICS THEORY OF OPERATION ARCHITECTURE GAIN SELECTION RG Power Dissipation REFERENCE TERMINAL INPUT VOLTAGE RANGE LAYOUT Common-Mode Rejection Ratio over Frequency Power Supplies and Grounding Reference Pin INPUT BIAS CURRENT RETURN PATH INPUT VOLTAGES BEYOND THE SUPPLY RAILS Input Voltages Beyond the Maximum Ratings RADIO FREQUENCY INTERFERENCE (RFI) CALCULATING THE NOISE OF THE INPUT STAGE Source Resistance Noise Voltage Noise of the Instrumentation Amplifier Current Noise of the Instrumentation Amplifier Total Noise Density Calculation APPLICATIONS INFORMATION DIFFERENTIAL OUTPUT CONFIGURATION DRIVING AN ADC OUTLINE DIMENSIONS ORDERING GUIDE
1
Excellent ac specifications
00
TOP VIEW
123-
10 MHz bandwidth (G = 1) (Not to Scale)
10
2 MHz bandwidth (G = 100)
Figure 1.
0.6 μs settling time to 0.001% (G = 10) 80 dB CMRR at 20 kHz (G = 1) 35 V/μs slew rate High precision dc performance (AD8421BRZ) 94 dB CMRR minimum (G = 1) 10µ G = 100 0.2 μV/°C maximum input offset voltage drift 1 ppm/°C maximum gain drift (G = 1) /√Hz) BEST AVAILABLE V 7mA LOW NOISE IN-AMP 500 pA maximum input bias current z ( 1µ kH Inputs protected to 40 V from opposite supply 1 T ±2.5 V to ±18 V dual supply (5 V to 36 V single supply) A ITY Gain set with a single resistor (G = 1 to 10,000) S 100n N E D APPLICATIONS E IS BEST AVAILABLE O 1mA LOW POWER IN-AMP Medical instrumentation 10n L N Precision data acquisition AD8421 TOTA Microphone preamplification RS NOISE ONLY Vibration analysis 1n100 1k 10k 100k 1M
078
Multiplexed input applications
23-
SOURCE RESISTANCE, RS (Ω)
101
ADC driver
Figure 2. Noise Density vs. Source Resistance
GENERAL DESCRIPTION
The AD8421 is a low cost, low power, extremely low noise, ultralow The AD8421 delivers 3 nV/√Hz input voltage noise and bias current, high speed instrumentation amplifier that is ideally 200 fA/√Hz current noise with only 2 mA quiescent current, suited for a broad spectrum of signal conditioning and data making it an ideal choice for measuring low level signals. For acquisition applications. This product features extremely high applications with high source impedance, the AD8421 employs CMRR, allowing it to extract low level signals in the presence of innovative process technology and design techniques to provide high frequency common-mode noise over a wide temperature noise performance that is limited only by the sensor. range. The AD8421 uses unique protection methods to ensure robust The 10 MHz bandwidth, 35 V/μs slew rate, and 0.6 μs settling inputs while still maintaining very low noise. This protection time to 0.001% (G = 10) allow the AD8421 to amplify high speed allows input voltages up to 40 V from the opposite supply rail signals and excel in applications that require high channel count, without damage to the part. multiplexed systems. Even at higher gains, the current feedback A single resistor sets the gain from 1 to 10,000. The reference architecture maintains high performance; for example, at G = 100, pin can be used to apply a precise offset to the output voltage. the bandwidth is 2 MHz and the settling time is 0.8 μs. The AD8421 has excellent distortion performance, making it suitable The AD8421 is specified from −40°C to +85°C and has typical for use in demanding applications such as vibration analysis. performance curves to 125°C. It is available in 8-lead MSOP and SOIC packages.
Rev. 0 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 license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Tel: 781.329.4700 www.analog.com Trademarks and registered trademarks are the property of their respective owners. Fax: 781.461.3113 ©2012 Analog Devices, Inc. All rights reserved.
Document Outline FEATURES APPLICATIONS PIN CONNECTION DIAGRAM GENERAL DESCRIPTION TABLE OF CONTENTS REVISION HISTORY SPECIFICATIONS AR AND BR GRADES ARM AND BRM GRADES ABSOLUTE MAXIMUM RATINGS THERMAL RESISTANCE ESD CAUTION PIN CONFIGURATION AND FUNCTION DESCRIPTIONS TYPICAL PERFORMANCE CHARACTERISTICS THEORY OF OPERATION ARCHITECTURE GAIN SELECTION RG Power Dissipation REFERENCE TERMINAL INPUT VOLTAGE RANGE LAYOUT Common-Mode Rejection Ratio over Frequency Power Supplies and Grounding Reference Pin INPUT BIAS CURRENT RETURN PATH INPUT VOLTAGES BEYOND THE SUPPLY RAILS Input Voltages Beyond the Maximum Ratings RADIO FREQUENCY INTERFERENCE (RFI) CALCULATING THE NOISE OF THE INPUT STAGE Source Resistance Noise Voltage Noise of the Instrumentation Amplifier Current Noise of the Instrumentation Amplifier Total Noise Density Calculation APPLICATIONS INFORMATION DIFFERENTIAL OUTPUT CONFIGURATION DRIVING AN ADC OUTLINE DIMENSIONS ORDERING GUIDE
