AD8278BRZ-RL

Low Power, Wide Supply Range, Low Cost Difference Amplifier, G = ½, 2 AD8278 FEATURES Wide input range beyond supplies Rugged input overvoltage protection Low supply current: 200 μA maximum Low power dissipation: 0.5 mW at VS = 2.5 V Bandwidth: 1 MHz (G = ½) CMRR: 80 dB minimum, dc to 20 kHz (G = ½) Low offset voltage drift: ±2 μV/°C maximum (B Grade) Low gain drift: 1 ppm/°C maximum (B Grade) Enhanced slew rate: 1.4 V/μs Wide power supply range: Single supply: 2 V to 36 V Dual supplies: ±2 V to ±18 V 8-lead SOIC and MSOP packages FUNCTIONAL BLOCK DIAGRAM +VS 7 AD8278 –IN 2 40kΩ 20kΩ 5 SENSE 6 OUT +IN 3 40kΩ 20kΩ 1 REF 08308-001 4 –VS Figure 1. Table 1. Difference Amplifiers by Category Low Distortion AD8270 AD8271 AD8273 AD8274 AMP03 1 APPLICATIONS Voltage measurement and monitoring Current measurement and monitoring Instrumentation amplifier building block Portable, battery-powered equipment Test and measurement High Voltage AD628 AD629 Current Sensing 1 AD8202 (U) AD8203 (U) AD8205 (B) AD8206 (B) AD8216 (B) Low Power AD8276 AD8277 U = unidirectional, B = bidirectional. GENERAL DESCRIPTION The AD8278 is a general-purpose difference amplifier intended for precision signal conditioning in power critical applications that require both high performance and low power. The AD8278 provides exceptional common-mode rejection ratio (80 dB) and high bandwidth while amplifying signals well beyond the supply rails. The on-chip resistors are laser-trimmed for excellent gain accuracy and high CMRR. They also have extremely low gain drift vs. temperature. The common-mode range of the amplifier extends to almost triple the supply voltage (for G = ½), making it ideal for singlesupply applications that require a high common-mode voltage range. The internal resistors and ESD circuitry at the inputs also provide overvoltage protection to the op amp. The AD8278 can be used as a difference amplifier with G = ½ or G = 2. It can also be connected in a high precision, singleended configuration for non-inverting and inverting gains of −½, −2, +3, +2, +1½, +1, or +½. The AD8278 provides an integrated precision solution that has a smaller size, lower cost, and better performance than a discrete alternative. The AD8278 operates on single supplies (2.0 V to 36 V) or dual supplies (±2 V to ±18 V). The maximum quiescent supply current is 200 μA, which makes it ideal for battery-operated and portable systems. The AD8278 is available in the space-saving 8-lead MSOP and SOIC packages. It is specified for performance over the industrial temperature range of −40°C to +85°C and is fully RoHS compliant. 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 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. Trademarks and registered trademarks are the property of their respective owners. One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. Tel: 781.329.4700 www.analog.com Fax: 781.461.3113 ©2009 Analog Devices, Inc. All rights reserved. AD8278 TABLE OF CONTENTS Features .............................................................................................. 1 Applications ....................................................................................... 1 Functional Block Diagram .............................................................. 1 General Description ......................................................................... 1 Revision History ............................................................................... 2 Specifications..................................................................................... 3 Absolute Maximum Ratings............................................................ 7 Thermal Resistance ...................................................................... 7 Maximum Power Dissipation ..................................................... 7 Short-Circuit Current .................................................................. 7 ESD Caution .................................................................................. 7 Pin Configurations and Function Descriptions ........................... 8 Typical Performance Characteristics ..............................................9 Theory of Operation ...................................................................... 16 Circuit Information.................................................................... 16 Driving the AD8278................................................................... 16 Input Voltage Range ................................................................... 16 Power Supplies ............................................................................ 17 Applications Information .............................................................. 18 Configurations ............................................................................ 18 Instrumentation Amplifier........................................................ 19 Outline Dimensions ....................................................................... 20 Ordering Guide .......................................................................... 21 REVISION HISTORY 7/09—Revision 0: Initial Version Rev. 0 | Page 2 of 24 AD8278 SPECIFICATIONS VS = ±5 V to ±15 V, VREF = 0 V, TA = 25°C, RL = 10 kΩ connected to ground, G = ½ difference amplifier configuration, unless otherwise noted. Table 2. G=½ Parameter INPUT CHARACTERISTICS System Offset1 vs. Temperature Average Temperature Coefficient vs. Power Supply Common-Mode Rejection Ratio (RTI) Input Voltage Range2 Impedance3 Differential Common Mode DYNAMIC PERFORMANCE Bandwidth Slew Rate Settling Time to 0.01% Settling Time to 0.001% GAIN Gain Error Gain Drift Gain Nonlinearity OUTPUT CHARACTERISTICS Output Voltage Swing4 Short-Circuit Current Limit Capacitive Load Drive NOISE5 Output Voltage Noise POWER SUPPLY Supply Current6 vs. Temperature Operating Voltage Range7 TEMPERATURE RANGE Operating Range 1 2 Conditions Min Grade B Typ Max 50 100 100 1 2.5 Min Grade A Typ Max 50 250 250 5 5 Unit μV μV μV/°C μV/V TA = −40°C to +85°C TA = −40°C to +85°C VS = ±5 V to ±18 V VS = ±15 V, VCM = ±27 V, RS = 0 Ω 0.3 2 80 −3(VS + 0.1) 120 30 1 1.4 +3(VS − 1.5) 74 −3(VS + 0.1) 120 30 1 1.4 dB +3(VS − 1.5) V kΩ kΩ MHz V/μs 9 10 0.01 0.05 5 10 μs μs % ppm/°C ppm 1.1 10 V step on output, CL = 100 pF 1.1 9 10 0.005 TA = −40°C to +85°C VOUT = 20 V p-p VS = ±15 V, RL = 10 kΩ TA = −40°C to +85°C 0.02 1 5 −VS + 0.2 ±15 200 +VS − 0.2 −VS + 0.2 ±15 200 1.4 47 +VS − 0.2 V mA pF μV p-p nV/√Hz μA μA V °C f = 0.1 Hz to 10 Hz f = 1 kHz 1.4 47 50 200 250 ±18 +125 50 200 250 ±18 +125 TA = −40°C to +85°C ±2 −40 ±2 −40 Includes input bias and offset current errors, RTO (referred to output) The input voltage range may also be limited by absolute maximum input voltage or by the output swing. See the Input Voltage Range section in the Theory of Operation for details. 3 Internal resistors are trimmed to be ratio matched and have ±20% absolute accuracy. 4 Output voltage swing varies with supply voltage and temperature. See Figure 20 through Figure 23 for details. 5 Includes amplifier voltage and current noise, as well as noise from internal resistors. 6 Supply current varies with supply voltage and temperature. See Figure 24 and Figure 26 for details. 7 Unbalanced dual supplies can be used, such as −VS = −0.5 V and +VS = +2 V. The positive supply rail must be at least 2 V above the negative supply and reference voltage. Rev. 0 | Page 3 of 24 AD8278 VS = ±5 V to ±15 V, VREF = 0 V, TA = 25°C, RL = 10 kΩ connected to ground, G = 2 difference amplifier configuration, unless otherwise noted. Table 3. G=2 Parameter INPUT CHARACTERISTICS System Offset 1 vs. Temperature Average Temperature Coefficient vs. Power Supply Common-Mode Rejection Ratio (RTI) Input Voltage Range 2 Impedance 3 Differential Common Mode DYNAMIC PERFORMANCE Bandwidth Slew Rate Settling Time to 0.01% Settling Time to 0.001% GAIN Gain Error Gain Drift Gain Nonlinearity OUTPUT CHARACTERISTICS Output Voltage Swing 4 Short-Circuit Current Limit Capacitive Load Drive NOISE 5 Output Voltage Noise POWER SUPPLY Supply Current 6 vs. Temperature Operating Voltage Range 7 TEMPERATURE RANGE Operating Range 1 2 Conditions Min Grade B Typ Max 100 200 200 2 5 Min Grade A Typ Max 100 500 500 5 10 Unit μV μV μV/°C μV/V dB V kΩ kΩ kHz V/μs TA = −40°C to +85°C TA = −40°C to +85°C VS = ±5 V to ±18 V VS = ±15 V, VCM = ±27 V, RS = 0 Ω 0.6 2 86 −1.5(VS + 0.1) 120 30 550 1.4 80 +1.5(VS − 1.5) −1.5(VS + 0.1) 120 30 550 1.4 +1.5(VS − 1.5) 1.1 10 V step on output, CL = 100 pF 1.1 10 11 10 11 0.01 0.05 5 10 μs μs % ppm/° C ppm 0.005 TA = −40°C to +85°C VOUT = 20 V p-p VS = ±15 V, RL = 10 kΩ TA = −40°C to +85°C 0.02 1 5 −VS + 0.2 ±15 350 +VS − 0.2 −VS + 0.2 ±15 350 2.8 90 +VS − 0.2 V mA pF μV p-p nV/√Hz μA μA V f = 0.1 Hz to 10 Hz f = 1 kHz 2.8 90 95 200 250 ±18 95 200 250 ±18 TA = −40°C to +85°C ±2 ±2 −40 +125 −40 +125 °C Includes input bias and offset current errors, RTO (referred to output). The input voltage range may also be limited by absolute maximum input voltage or by the output swing. See the Input Voltage Range section in the Theory of Operation for details. 3 Internal resistors are trimmed to be ratio matched and have ±20% absolute accuracy. 4 Output voltage swing varies with supply voltage and temperature. See Figure 20 through Figure 23 for details. 5 Includes amplifier voltage and current noise, as well as noise from internal resistors. 6 Supply current varies with supply voltage and temperature. See Figure 24 and Figure 26 for details. 7 Unbalanced dual supplies can be used, such as −VS = −0.5 V and +VS = +2 V. The positive supply rail must be at least 2 V above the negative supply and reference voltage. Rev. 0 | Page 4 of 24 AD8278 VS = +2.7 V to