INA ® INA2141 214 INA 1 214 1 Dual, Low Power, G = 10, 100 INSTRUMENTATION AMPLIFIER FEATURES DESCRIPTION ● LOW OFFSET VOLTAGE: 50µV max ● LOW DRIFT: 0.5µV/°C max The INA2141 is a low power, dual instrumentation amplifier offering excellent accuracy. Its versatile 3-op amp design and small size make it ideal for a wide range of applications. Current-feedback input circuitry provides wide bandwidth even at high gain (200kHz at G = 100). ● EXCELLENT GAIN ACCURACY: ±0.05% max at G = 10 ● LOW INPUT BIAS CURRENT: 5nA max ● HIGH CMR: 117dB min (G = 100) ● INPUTS PROTECTED TO ±40V Simple pin connections set an accurate gain of 10 or 100V/V without external resistors. Internal input protection can withstand up to ±40V without damage. ● WIDE SUPPLY RANGE: ±2.25V to ±18V ● LOW QUIESCENT CURRENT: 750µA/IA The INA2141 is laser trimmed for very low offset voltage (50µV), drift (0.5µV/°C) and high commonmode rejection (117dB at G = 100). It operates with power supplies as low as ±2.25V, and quiescent current is only 750µA per amplifier—ideal for battery operated systems. ● 16-PIN PLASTIC DIP, SOL-16 APPLICATIONS ● SENSOR AMPLIFIER THERMOCOUPLE, RTD, BRIDGE ● MEDICAL INSTRUMENTATION Packages are 16-pin plastic DIP, and SOL-16 surface-mount, specified for the –40°C to +85°C temperature range. ● MULTIPLE CHANNEL SYSTEMS V+ – VINA G = 10 or 100 1 Over-Voltage Protection 3 252Ω 4 5050Ω 252Ω 2 Over-Voltage Protection – 16 Over-Voltage Protection VINB G = 10 or 100 + VINB 14 252Ω 13 5050Ω 252Ω 15 INA2141 7 A1A 40kΩ 40kΩ 25kΩ + VINA 9 A3A 6 VOA 25kΩ 5 A2A 40kΩ 40kΩ 40kΩ 40kΩ Ref 10 A1B 25kΩ A3B 11 VOB 25kΩ Over-Voltage Protection 12 A2B 40kΩ Ref 40kΩ 8 V– International Airport Industrial Park • Mailing Address: PO Box 11400, Tucson, AZ 85734 • Street Address: 6730 S. Tucson Blvd., Tucson, AZ 85706 • Tel: (520) 746-1111 • Twx: 910-952-1111 Internet: http://www.burr-brown.com/ • FAXLine: (800) 548-6133 (US/Canada Only) • Cable: BBRCORP • Telex: 066-6491 • FAX: (520) 889-1510 • Immediate Product Info: (800) 548-6132 ©1995 Burr-Brown Corporation PDS-1244C Printed in U.S.A. January, 1996 SPECIFICATIONS At TA = +25°C, VS = ±15V, and RL = 10kΩ, unless otherwise noted. INA2141P, U PARAMETER CONDITIONS INPUT Offset Voltage, RTI vs Temperature vs Power Supply Long-Term Stability Safe Input Voltage Common-Mode Rejection TYP MAX ±50 ±100 ±0.5 ±2 ±2 ±10 (V+) – 2 (V–) + 2 ±20 ±50 ±0.2 ±0.5 ±1 ±2 0.2 0.5 1010 || 2 1010 || 9 (V+) – 1.4 (V–) + 1.7 117 97 125 106 G = 100 G = 10 G = 100 G = 10(2) VS = ±2.25 to ±18V, G = 100 G = 10 G = 100 G = 10 Impedance, Differential Common-Mode Common-Mode Voltage Range(1) VO = 0V VCM = ±13V, ∆RS = 1kΩ G = 100 G = 10 ±2 ±30 ±1 ±30 BIAS CURRENT vs Temperature Offset Current vs Temperature NOISE VOLTAGE, RTI f = 10Hz f = 100Hz f = 1kHz fB = 0.1Hz to 10Hz f = 10Hz f = 100Hz f = 1kHz fB = 0.1Hz to 10Hz Noise Current f = 10Hz f = 1kHz fB = 0.1Hz to 10Hz GAIN Gain Error Gain vs Temperature(2) Nonlinearity G = 100, RS = 0Ω G = 10, RS = 0Ω VO = ±13.6V, G = 100 G = 10 G = 10, 100 G = 100 G = 10 OUTPUT Voltage: Positive Negative Load Capacitance Stability Short-Circuit Current FREQUENCY RESPONSE Bandwidth, –3dB RL = 10kΩ RL = 10kΩ Overload Recovery G = 100 G = 10 VO = ±10V, G = 10 VO = ±5V, G = 100 G = 10 50% Overdrive POWER SUPPLY Voltage Range Current, Total VIN = 0V Slew Rate Settling Time, 0.01% TEMPERATURE RANGE Specification Operating θJA INA2141PA, UA MIN TYP MAX UNITS ±125 ±250 ±1.5 ±5 ±5 ±20 ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ µV µV µV/°C µV/°C µV/V µV/V µV/mo µV/mo Ω || pF Ω || pF V V V 110 93 120 100 ±40 ✻ ±5 ✻ ✻ ✻ ✻ ±5 ±10 ±10 nA pA/°C nA pA/°C ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ nV/√Hz nV/√Hz nV/√Hz µVp-p nV/√Hz nV/√Hz nV/√Hz µVp-p 0.9 0.3 30 ✻ ✻ ✻ pA/√Hz pA/√Hz pAp-p ±0.075 ±0.05 ±10 ±0.002 ±0.001 ✻ ✻ ✻ ✻ ✻ ✻ ✻ (V+) – 0.9 (V–) + 0.9 1000 +6/–15 200 1 4 9 7 4 ±2.25 dB dB 10 8 8 0.2 22 13 12 0.6 ±0.03 ±0.01 ±2 ±0.0005 ±0.0003 (V+) – 1.4 (V–) + 1.4 MIN ±15 ±1.5 –40 –40 ±18 ±1.6 ✻ 85 125 ✻ ✻ 80 ±0.15 ±0.15 ✻ ±0.004 ±0.002 % % ppm/°C % of FSR % of FSR ✻ ✻ ✻ ✻ V V pF mA ✻ ✻ ✻ ✻ ✻ ✻ kHz MHz V/µs µs µs µs ✻ ✻ ✻ ✻ ✻ V mA ✻ ✻ °C °C °C/W ✻ Specification same as INA2141P, U. NOTE: (1) Input common-mode range varies with output voltage—see typical curves. (2) Guaranteed by wafer test. The information provided herein is believed to be reliable; however, BURR-BROWN assumes no responsibility for inaccuracies or omissions. BURR-BROWN assumes no responsibility for the use of this information, and all use of such information shall be entirely at the user’s own risk. Prices and specifications are subject to change without notice. No patent rights or licenses to any of the circuits described herein are implied or granted to any third party. BURR-BROWN does not authorize or warrant any BURR-BROWN product for use in life support devices and/or systems. ® INA2141 2 PIN CONFIGURATION Top View ELECTROSTATIC DISCHARGE SENSITIVITY DIP SOL-16 – VINA 1 – 16 VINB + VINA 2 + 15 VINB JA 3 14 JB JA 4 13 JB RefA 5 12 RefB VOA 6 11 VOB SenseA 7 10 SenseB V– 8 9 This integrated circuit can be damaged by ESD. Burr-Brown recommends that all integrated circuits be handled with appropriate precautions. Failure to observe proper handling and installation procedures can cause damage. ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more susceptible to damage because very small parametric changes could cause the device not to meet its published specifications. V+ ORDERING INFORMATION ABSOLUTE MAXIMUM RATINGS Supply Voltage .................................................................................. ±18V Analog Input Voltage Range ............................................................. ±40V Output Short-Circuit (to ground) .............................................. Continuous Operating Temperature ................................................. –40°C to +125°C Storage Temperature ..................................................... –40°C to +125°C Junction Temperature .................................................................... +150°C Lead Temperature (soldering, 10s) ............................................... +300°C PRODUCT PACKAGE PACKAGE DRAWING NUMBER(1) INA2141PA INA2141P INA2141UA INA2141U 16-Pin Plastic DIP 16-Pin Plastic DIP SOL-16 Surface-Mount SOL-16 Surface-Mount 180 180 211 211 TEMPERATURE RANGE –40°C to +85°C –40°C to +85°C –40°C to +85°C –40°C to +85°C NOTE: (1) For detailed drawing and dimension table, please see end of data sheet, or Appendix C of Burr-Brown IC Data Book. ® 3 INA2141 TYPICAL PERFORMANCE CURVES At TA = +25°C, and VS = ±15V, unless otherwise noted. COMMON-MODE REJECTION vs FREQUENCY GAIN vs FREQUENCY 60 140 Common-Mode Rejection (dB) 50 40 Gain (dB) G = 100V/V 30 20 G = 10V/V 10 0 –10 –20 G = 10V/V 100 80 60 40 20 0 1k 10k 100k 1M 10M 10 100 1k 100k 10k Frequency (Hz) Frequency (Hz) POSITIVE POWER SUPPLY REJECTION vs FREQUENCY NEGATIVE POWER SUPPLY REJECTION vs FREQUENCY 140 140 120 120 100 Power Supply Rejection (dB) Power Supply Rejection (dB) G = 100V/V 120 G = 100V/V 80 60 G = 10V/V 40 1M G = 100V/V 100 80 60 40 G = 10V/V 20 20 0 0 10 100 1k 10k 100k 10 1M 100 1k 10k 100k Frequency (Hz) Frequency (Hz) INPUT COMMON-MODE RANGE vs OUTPUT VOLTAGE, VS = ±15V INPUT COMMON-MODE RANGE vs OUTPUT VOLTAGE, VS = ±5, ±2.5V 15 1M 5 Common-Mode Voltage (V) Common-Mode Voltage (V) 4 10 5 VD/2 0 VD/2 + –5 VCM +15V – VO + – Ref + –15V –10 3 2 1 0 –1 –2 –3 VS = ±5V VS = ±2.5V –4 –15 –15 –10 –5 0 5 10 –5 –5 15 Output Voltage (V) –3 –2 –1 0 1 Output Voltage (V) ® INA2141 –4 4 2 3 4 5 TYPICAL PERFORMANCE CURVES (CONT) At TA = +25°C, and VS = ±15V, unless otherwise noted. CROSSTALK vs FREQUENCY INPUT- REFERRED NOISE vs FREQUENCY G = 100V/V 120 G = 10V/V Crosstalk (dB) 100 80 60 40 20 0 100 1k 10 100 G = 10V/V 1 10 G = 100 Current Noise 0.1 1 10 100 1k 10k 100k 1M Input Bias Current Noise (pA/√ Hz) Input-Referred Voltage Noise (nV/√ Hz) 140 1 10 100 Frequency (Hz) 1k 10k Frequency (Hz) QUIESCENT CURRENT and SLEW RATE vs TEMPERATURE INPUT OVER-VOLTAGE V/I CHARACTERISTICS 1.8 6 1.7 5 5 4 Slew Rate 1.5 3 IQ 1.4 Input Current (mA) 1.6 3 Slew Rate (V/µs) Quiescent Current (µA) 4 Flat region represents normal linear operation. 2 G = 10V/V 0 –1 +15V G = 10V/V –2 –3 2 G = 100V/V 1 1/2 INA2141 G = 100V/V VIN –4 1.3 –75 –50 –25 0 25 50 75 100 IIN –15V –5 1 125 –50 –40 –30 –20 –10 0 10 20 30 40 50 Input Voltage (V) Temperature (°C) INPUT BIAS CURRENT vs TEMPERATURE OFFSET VOLTAGE WARM-UP 2 10 G = 100V/V 6 Input Bias Current (nA) Offset Voltage Change (µV) 8 4 2 0 –2 –4 IB 1 IOS 0 Typical IB and IOS Range ±2nA at 25°C –1 –6 –8 –2 –10 0 10 20 30 40 50 –75 Time (ms) –50 –25 0 25 50 75 100 125 Temperature (°C) ® 5 INA2141 TYPICAL PERFORMANCE CURVES (CONT) At TA = +25°C, and VS = ±15V, unless otherwise noted. OUTPUT VOLTAGE SWING vs POWER SUPPLY VOLTAGE V+ (V+)–0.4 (V+)–0.4 Output Voltage Swing (V) (V+) (V+)–0.8 (V+)–1.2 (V+)+1.2 (V–)+0.8 +25°C +85°C (V+)–0.8 –40°C (V+)–1.2 RL = 10kΩ (V–)+1.2 +25°C –40°C (V–)+0.8 (V–)+0.4 (V–)+0.4 +85°C –40°C 0 1 2 3 0 4 Output Current (mA) 5 10 15 20 Power Supply Voltage (V) SHORT-CIRCUIT OUTPUT CURRENT vs TEMPERATURE MAXIMUM OUTPUT VOLTAGE vs FREQUENCY 30 16 Peak-to-Peak Output Voltage (Vpp) –ISC 14 Short Circuit Current (mA) +85°C V– V– 12 10 8 6 4 +ISC 2 G = 10, 100 25 20 15 10 5 0 0 –75 –50 –25 0 25 50 75 100 1k 125 10k 100k 1M Frequency (Hz) Temperature (°C) VOLTAGE NOISE 0.1 to 10Hz INPUT-REFERRED, G = 100 TOTAL HARMONIC DISTORTION + NOISE vs FREQUENCY 1 VO = 1Vrms 500kHz Measurement Bandwidth THD+N (%) Output Voltage (V) OUTPUT VOLTAGE SWING vs OUTPUT CURRENT 0.1 RL = 10kΩ G = 100, RL = 100kΩ 0.1µV/div 0.01 G = 10V/V RL = 100kΩ Dashed Portion is noise limited. 0.001 100 1k 10k 100k 1s/div Frequency (Hz) ® INA2141 6 TYPICAL PERFORMANCE CURVES (CONT) At TA = +25°C, and VS = ±15V unless otherwise noted. SMALL-SIGNAL STEP RESPONSE LARGE-SIGNAL STEP RESPONSE G = 10 G = 10 20mV/div 5V/div G = 100 G = 100 5µs/div 5µs/div ® 7 INA2141 APPLICATION INFORMATION Internal resistor ratios are laser trimmed to assure excellent gain accuracy. Actual resistor values can vary by approximately ±25% from the nominal values shown. Figure 1 shows the basic connections required for operation of the INA2141. Applications with noisy or high impedance power supplies may require decoupling capacitors close to the device pins as shown. Gains between 10 and 100 can be achieved by connecting an external resistor to the jumper pins. This is not recommended, however, because the ±25% variation of internal resistor values makes the required external resistor value uncertain. A companion model, INA2128, features accurately trimmed internal resistors so that gains from 1 to 10,000 can be set with an external resistor. The output is referred to the output reference (Ref) terminals (RefA and RefB) which are normally grounded. These must be low-impedance connections to assure good commonmode rejection. A resistance of 8Ω in series with a Ref pin will cause a typical device to degrade to approximately 80dB CMR (G = 1). The INA2141 has a separate output sense feedback connections SenseA and SenseB. These must be connected to their respective output terminals for proper operation. The output sense connection can be used to sense the output voltage directly at the load for best accuracy. DYNAMIC PERFORMANCE The typical performance curve “Gain vs Frequency” shows that despite its low quiescent current, the INA2141 achieves wide bandwidth, even at high gain. This is due to its currentfeedback topology. Settling time also remains excellent at high gain. SETTING THE GAIN Gain of each IA can be independently selected with a jumper connection as shown in Figure 1. G = 10V/V with no jumper installed. With a jumper installed G = 100V/V. To preserve good gain accuracy, this jumper must have low series resistance. A resistance of 0.5Ω in series with the jumper will decrease the gain by 0.1%. NOISE PERFORMANCE The INA2141 provides very low noise in most applications. Low frequency noise is approximately 0.2µVp-p measured from 0.1 to 10Hz (G = 100). This provides dramatically improved noise when compared to state-of-the-art chopperstabilized amplifiers. V+ 0.1µF Pin numbers for Channel B shown in parenthesis. – VIN G = 10V/V Open Circuit J 1 (16) 9 INA2141 Over-Voltage Protection 40kΩ 3 (14) 252Ω + VIN (13) 2 (15) 6 (11) A3 25kΩ Load VO 252Ω – Ref A2 Over-Voltage Protection 40kΩ 8 40kΩ 5 (12) 0.1µF V– Also drawn in simplified form: – VIN INA2141 + VIN VO Ref FIGURE 1. Basic Connections. ® INA2141 + – ) VO = G • (VIN – VIN + 4 J 40kΩ 25kΩ 5050Ω G = 100V/V Connect Jumper 7 Sense (10) A1 8 NOTE: If channel is unused, connect inputs to ground, sense to VO, and leave Ref open-circuit. OFFSET TRIMMING The INA2141 is laser trimmed for low offset voltage and offset voltage drift. Most applications require no external offset adjustment. Figure 2 shows an optional circuit for trimming the output offset voltage. The voltage applied to Ref terminal is summed with the output. The op amp buffer provides low impedance at the Ref terminal to preserve good common-mode rejection. – VIN VO 1/2 INA2141 47kΩ V+ 1/2 INA2141 V+ Microphone, Hydrophone etc. 47kΩ 1/2 INA2141 Thermocouple 100µA 1/2 REF200 Ref IN 10kΩ OPA177 10kΩ 100Ω (For other channel) ±10mV Adjustment Range 1/2 INA2141 100Ω 100µA 1/2 REF200 Center-tap provides bias current return. V– FIGURE 2. Optional Trimming of Output Offset Voltage. FIGURE 3. Providing an Input Common-Mode Current Path. INPUT BIAS CURRENT RETURN PATH The input impedance of the INA2141 is extremely high— approximately 1010Ω. However, a path must be provided for the input bias current of both inputs. This input bias current is approximately ±2nA. High input impedance means that this input bias current changes very little with varying input voltage. mon-mode input range is related to the output voltage of the complete amplifier. This behavior also depends on supply voltage—see performance curves “Input Common-Mode Range vs Output Voltage”. Input-overload can produce an output voltage that appears normal. For example, if an input overload condition drives both input amplifiers to their positive output swing limit, the difference voltage measured by the output amplifier will be near zero. The output of the INA2141 will be near 0V even though both inputs are overloaded. Input circuitry must provide a path for this input bias current for proper operation. Figure 3 shows various provisions for an input bias current path. Without a bias current path, the inputs will float to a potential which exceeds the commonmode range of the INA2141 and the input amplifiers will saturate. LOW VOLTAGE OPERATION The INA2141 can be operated on power supplies as low as ±2.25V. Performance remains excellent with power supplies ranging from ±2.25V to ±18V. Most parameters vary only slightly throughout this supply voltage range—see typical performance curves. Operation at very low supply voltage requires careful attention to assure that the input voltages remain within their linear range. Voltage swing requirements of internal nodes limit the input commonmode range with low power supply voltage. Typical performance curves, “Input Common-Mode Range vs Output Voltage” show the range of linear operation for ±15V, ±5V, and ±2.5V supplies. If the differential source resistance is low, the bias current return path can be connected to one input (see the thermocouple example in Figure 3). With higher source impedance, using two equal resistors provides a balanced input with possible advantages of lower input offset voltage due to bias current and better high-frequency common-mode rejection. INPUT COMMON-MODE RANGE The linear input voltage range of the input circuitry of the INA2141 is from approximately 1.4V below the positive supply voltage to 1.7V above the negative supply. As a differential input voltage causes the output voltage increase, however, the linear input range will be limited by the output voltage swing of amplifiers A1 and A2. So the linear com- ® 9 INA2141 INPUT PROTECTION The inputs of the INA2141 are individually protected for voltages up to ±40V. For example, a condition of –40V on one input and +40V on the other input will not cause damage. Internal circuitry on each input provides low series impedance under normal signal conditions. To provide equivalent protection, series input resistors would contribute excessive noise. If the input is overloaded, the protection circuitry limits the input current to a safe value of approximately 1.5 to 5mA. The typical performance curve “Input Bias Current vs Common-Mode Input Voltage” shows this input current limit behavior. The inputs are protected even if the power supplies are disconnected or turned off. there is virtually no signal coupling between channels. Crosstalk increases with frequency and is dependent on circuit gain, source impedance and signal characteristics. As source impedance increases, careful circuit layout will help achieve lowest channel crosstalk. Most crossstalk is produced by capacitive coupling of signals from one channel to the input section of the other channel. To minimize coupling, separate the input traces as far as practical from any signals associated with the opposite channel. A grounded guard trace surrounding the inputs helps reduce stray coupling between channels. Run the differential inputs of each channel parallel to each other or directly adjacent on top and bottom side of a circuit board. Stray coupling then tends to produce a common-mode signal which is rejected by the IA’s input. CHANNEL CROSSTALK The two channels of the INA2141 are completely independent, including all bias circuitry. At DC and low frequency VEX X-axis 1/2 INA2141 V1 X-axis VO VO = 10 (V2 – V1) + 10 (V4 – V3) 1/2 INA2141 Ref V2 VEX V3 1/2 INA2141 Y-axis Ref 1/2 INA2141 V4 Y-axis VO FIGURE 4. Two-Axis Bridge Amplifier. FIGURE 5. Sum of Differences Amplifier. 1/4 OPA4131 1/2 INA2141 1/4 OPA4131 LA RA 20kΩ 390kΩ 1/4 OPA4131 RL VG 1/4 OPA4131 10kΩ 390kΩ FIGURE 6. ECG Amplifier With Right-Leg Drive. ® INA2141 10 VO Ref G = 10 20kΩ