Datasheet AD8295 (Analog Devices)

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Precision Instrumentation Amplifier with Signal Processing Amplifiers AD8295 FEATURES CONNECTION DIAGRAM +V OUT A2 +IN A2 –IN Saves board space S 16 15 14 13 Includes precision in-amp, 2 op amps, and AD8295 2 matched resistors –IN 1 12 A2 OUT A2 4 mm × 4 mm LFCSP No heat slug for more routing room RG 2 11 A1 +IN Differential output fully specified IA In-amp specifications RG 3 10 A1 R1 Gain set with 1 external resistor (gain range: 1 to 1000) R1 A1 20kΩ Input voltage noise: 8 nV/√Hz maximum at 1 kHz R2 CMRR (G = 1): 90 dB minimum +IN 4 20kΩ 9 A1 –IN Input bias current: 0.8 nA maximum
1
5 6 7 8
00 3-
−3 dB bandwidth (G = 1): 1.2 MHz –V REF A1 OUT A1 R2 S
34 07
Slew rate: 2 V/μs
Figure 1.
Wide power supply range: ±2.3 V to ±18 V 1 ppm/°C, 0.03% resistor matching APPLICATIONS Table 1. Instrumentation Amplifiers by Category1 General- Zero Military Low High Speed Industrial process controls Purpose Drift Grade Power PGA Wheatstone bridges
AD8220 AD8231 AD620 AD8236 AD8250
Precision data acquisition systems
AD8221 AD8553 AD621 AD627 AD8251
Medical instrumentation
AD8222 AD8555 AD524 AD623 AD8253
Strain gages
AD8224 AD8556 AD526 AD8223
Transducer interfaces
AD8228 AD8557 AD624 AD8226
Differential output
AD8295 AD8293 AD8227 1 See www.analog.com for the latest selection of instrumentation amplifiers.
GENERAL DESCRIPTION
The AD8295 includes a high performance, programmable gain The AD8295 contains all the components necessary for a instrumentation amplifier. Gain is set from 1 to 1000 with a precision instrumentation amplifier front end in one small single resistor. The low noise and excellent common-mode 4 mm × 4 mm package. It contains a high performance rejection of the AD8295 enable the part to easily detect small instrumentation amplifier, two general-purpose operational signals even in the presence of large common-mode interference. amplifiers, and two precisely matched 20 kΩ resistors. For a similar instrumentation amplifier without the associated signal conditioning circuitry, see the AD8221 or AD8222 data The AD8295 is designed to make PCB routing easy and sheet. efficient. The AD8295 components are arranged in a logical way so that typical application circuits have short routes and The AD8295 operates on both single and dual supplies and is few vias. Unlike most chip scale packages, the AD8295 does not well suited for applications where ±10 V input voltages are have an exposed metal pad on the back of the part, which frees encountered. Performance is specified over the entire industrial additional space for routing and vias. The logical pin arrange- temperature range of −40°C to +85°C for all grades. The ment and routing freedom enable the AD8295 to offer simple AD8295 is operational from −40°C to +125°C; see the Typical pin-strapped solutions for complex systems in the equivalent Performance Characteristics section for expected operation up board space of a typical MSOP package. to 125°C.
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 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 ©2008–2009 Analog Devices, Inc. All rights reserved.
Document Outline FEATURES APPLICATIONS CONNECTION DIAGRAM GENERAL DESCRIPTION TABLE OF CONTENTS REVISION HISTORY SPECIFICATIONS INSTRUMENTATION AMPLIFIER SPECIFICATIONS, SINGLE-ENDED AND DIFFERENTIAL OUTPUT CONFIGURATIONS OP AMP SPECIFICATIONS INTERNAL RESISTOR NETWORK POWER AND TEMPERATURE SPECIFICATIONS ABSOLUTE MAXIMUM RATINGS THERMAL CHARACTERISTICS ESD CAUTION PIN CONFIGURATION AND FUNCTION DESCRIPTIONS TYPICAL PERFORMANCE CHARACTERISTICS IN-AMP OP AMPS SYSTEM THEORY OF OPERATION UNCOMMITTED OP AMPS INSTRUMENTATION AMPLIFIER Gain Selection Common-Mode Input Voltage Range Reference Terminal LAYOUT Routing and Vias Common-Mode Rejection over Frequency Unused Op Amps Reference Power Supplies INPUT PROTECTION INPUT BIAS CURRENT RETURN PATH RF INTERFERENCE DIFFERENTIAL OUTPUT APPLICATIONS INFORMATION CREATING A REFERENCE VOLTAGE AT MIDSCALE HIGH ACCURACY G = −1 CONFIGURATION WITH LOW-PASS FILTER TWO-POLE SALLEN-KEY FILTER AC-COUPLED INSTRUMENTATION AMPLIFIER DRIVING DIFFERENTIAL ADCs OUTLINE DIMENSIONS ORDERING GUIDE