Low Power, Wide Supply Range, Low Cost Difference Amplifiers, G = , 2 AD8278/AD8279 FEATURES FUNCTIONAL BLOCK DIAGRAMS +VS Wide input range beyond supplies 7 Rugged input overvoltage protection AD8278 40k 20k Low supply current: 200 A maximum (per amplifier) 2 IN 5 SENSE Low power dissipation: 0.5 mW at V = 2.5 V S Bandwidth: 1 MHz (G = ) 6 OUT CMRR: 80 dB minimum, dc to 20 kHz (G = , B Grade) Low offset voltage drift: 1 V/C maximum (B Grade) 40k 20k Low gain drift: 1 ppm/C maximum (B Grade) 3 1 +IN REF Enhanced slew rate: 1.4 V/s 4 Wide power supply range VS Single supply: 2 V to 36 V Figure 1. AD8278 Dual supplies: 2 V to 18 V +VS 8-lead SOIC, 14-lead SOIC, and 8-lead MSOP packages 11 AD8279 APPLICATIONS 40k 20k 2 INA 12 SENSEA Voltage measurement and monitoring Current measurement and monitoring 13 OUTA Instrumentation amplifier building block 3 14 +INA REFA Portable, battery-powered equipment 40k 20k 40k 20k Test and measurement 6 INB 10 SENSEB GENERAL DESCRIPTION 9 OUTB The AD8278 and AD8279 are general-purpose difference 5 8 +INB REFB amplifiers intended for precision signal conditioning in power 40k 20k critical applications that require both high performance and low 4 VS power. The AD8278 and AD8279 provide exceptional common- Figure 2. AD8279 mode rejection ratio (80 dB) and high bandwidth while amplifying input signals that are well beyond the supply rails. The on-chip Table 1. Difference Amplifiers by Category resistors are laser trimmed for excellent gain accuracy and high Low CMRR. They also have extremely low gain drift vs. temperature. 1 Distortion High Voltage Current Sensing Low Power The common-mode range of the amplifier extends to almost AD8270 AD628 AD8202 (U) AD8276 triple the supply voltage (for G = ), making the amplifer ideal AD8271 AD629 AD8203 (U) AD8277 for single-supply applications that require a high common- AD8273 AD8205 (B) mode voltage range. The internal resistors and ESD circuitry at AD8274 AD8206 (B) the inputs also provide overvoltage protection to the op amp. AMP03 AD8216 (B) The AD8278 and AD8279 can be used as difference amplifiers with 1 U = unidirectional, B = bidirectional. G = or G = 2. They can also be connected in a high precision, The AD8278 is available in the space-saving 8-lead MSOP and single-ended configuration for non inverting and inverting gains of SOIC packages, and the AD8279 is offered in a 14-lead SOIC , 2, +3, +2, +1, +1, or +. The AD8278 and AD8279 package. Both are specified for performance over the industrial provide an integrated precision solution that has a smaller size, temperature range of 40C to +85C and are fully RoHS lower cost, and better performance than a discrete alternative. compliant. The AD8278 and AD8279 operate on single supplies (2.0 V to 36 V) or dual supplies (2 V to 18 V). The maximum quiescent supply current is 200 A, which is ideal for battery-operated and portable systems. For unity-gain difference amplifiers with similar performance, refer to the AD8276 and AD8277 data sheets. Rev. C 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. 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Trademarks and registered trademarks are the property of their respective owners. 08308-001 08308-058AD8278/AD8279 TABLE OF CONTENTS Features .............................................................................................. 1 Typical Performance Characteristics ..............................................9 Applications....................................................................................... 1 Theory of Operation ...................................................................... 16 General Description ......................................................................... 1 Circuit Information.................................................................... 16 Functional Block Diagrams............................................................. 1 Driving the AD8278 and AD8279 ........................................... 16 Revision History ............................................................................... 2 Input Voltage Range................................................................... 16 Specifications..................................................................................... 3 Power Supplies............................................................................ 17 Absolute Maximum Ratings............................................................ 7 Applications Information .............................................................. 18 Thermal Resistance ...................................................................... 7 Configurations............................................................................ 18 Maximum Power Dissipation ..................................................... 7 Differential Output .................................................................... 19 Short-Circuit Current .................................................................. 7 Instrumentation Amplifier........................................................ 19 ESD Caution.................................................................................. 7 Outline Dimensions....................................................................... 20 Pin Configurations and Function Descriptions ........................... 8 Ordering Guide .......................................................................... 21 REVISION HISTORY 1/11Rev. B to Rev. C Change to Table 3 ..............................................................................4 Change to Impedance/Differential Parameter, Table 3 ............... 4 Change to Table 4 ..............................................................................5 Change to Impedance/Differential Parameter, Table 5 ............... 6 Change to Table 5 ..............................................................................6 Added Figure 6 and Table 9 .............................................................8 4/10Rev. A to Rev. B Changes to Figure 31 and Figure 32............................................. 13 Changes to Figure 40, Figure 41, and Figure 42 ......................... 14 Changed Supply Current Parameters to AD8278 Supply Current Parameter and AD8279 Supply Current Parameter, Table 5 ...... 6 Added Figure 47 Renumbered Sequentially .............................. 15 Updated Outline Dimensions ....................................................... 20 Changes to Figure 51 to Figure 57................................................ 18 Added Differential Output Section.............................................. 19 10/09Rev. 0 to Rev. A Changes to Figure 59...................................................................... 19 Added AD8279 and 14-Lead SOIC Model .....................Universal Updated Outline Dimensions....................................................... 21 Changes to Features.......................................................................... 1 Changes to Ordering Guide .......................................................... 21 Changes to General Description .................................................... 1 Change to Table 2 ............................................................................. 3 7/09Revision 0: Initial Version Rev. C Page 2 of 24