® INA157 INA 157 For most current data sheet and other product information, visit www.burr-brown.com High-Speed, Precision DIFFERENCE AMPLIFIER FEATURES APPLICATIONS ● DESIGNED FOR LOW COST ● DIFFERENTIAL INPUT AMPLIFIER ● LOW OFFSET VOLTAGE: ±500µV max ● LOW OFFSET DRIFT: ±2µV/°C ● INSTRUMENTATION AMPLIFIER BUILDING BLOCK ● G = 1/2 AMPLIFIER ● LOW GAIN ERROR: ±0.05% max ● WIDE BANDWIDTH: 3MHz ● G = 2 AMPLIFIER ● DIFFERENTIAL CURRENT RECEIVER ● HIGH SLEW RATE: 14V/µs ● FAST SETTLING TIME: 3µs to 0.01% ● VOLTAGE-CONTROLLED CURRENT SOURCE ● GROUND LOOP ELIMINATOR ● WIDE SUPPLY RANGE: ±4V to ±18V ● LOW QUIESCENT CURRENT: 2.4mA ● CURRENT SHUNT MONITOR ● SO-8 SURFACE-MOUNT PACKAGE DESCRIPTION V+ The INA157 is a high slew rate, G = 1/2 or G = 2 difference amplifier consisting of a precision op amp with a precision resistor network. The on-chip resistors are laser trimmed for accurate gain and high common-mode rejection. Excellent TCR tracking of the resistors maintains gain accuracy and commonmode rejection over temperature. The input commonmode voltage range extends beyond the positive and negative supply rails. It operates on ±4V to ±18V supplies. The difference amplifier is the foundation of many commonly used circuits. The INA157 provides this circuit function without using an expensive precision resistor network. The INA157 is available in a SO-8 surface-mount package and is specified for operation over the extended industrial temperature range, –40°C to +85°C. 7 –In 2 12kΩ 6kΩ 5 6 +In 3 12kΩ 6kΩ 1 Sense Output Ref 4 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/ • Cable: BBRCORP • Telex: 066-6491 • FAX: (520) 889-1510 • Immediate Product Info: (800) 548-6132 ©1999 Burr-Brown Corporation PDS-1483B Printed in U.S.A. March, 1999 SPECIFICATIONS: VS = ±15V At TA = +25°C, VS = ±15V, RL = 2kΩ connected to ground, and reference pin connected to ground, unless otherwise noted. INA157U PARAMETER CONDITIONS VOLTAGE(1) OFFSET Initial(1) vs Temperature vs Power Supply vs Time MIN OUTPUT VOLTAGE NOISE(3) f = 0.1Hz to 10Hz f = 1kHz GAIN Initial Error vs Temperature Nonlinearity VS = ±4V to ±18V VCM VO = 0V 3(V+)–7.5 VO = 0V 3(V–)+7.5 = –37.5V to 37.5V, RS = 0Ω 86 ✽ ✽ 80 3(V+)–6 3(V–)+3 96 1.3 26 0.5 ±0.01 ±1 ±0.0001 VO = –10V to +10V TEMPERATURE RANGE Specified Operation Storage Thermal Resistance, ΘJA SO-8 Surface-Mount ±500 ±20 ±60 TYP MAX UNITS ✽ ✽ ✽ ✽ ±1000 ✽ ✽ µV µV/°C µV/V µV/mo ✽ ✽ kΩ kΩ ✽ ✽ ✽ V V dB ✽ ✽ µVp-p nV/√Hz RTO OUTPUT Voltage, Positive Negative Current Limit, Continuous to Common Capacitive Load (stable operation) POWER SUPPLY Rated Voltage Operating Voltage Range Quiescent Current ±100 ±2 ±5 0.25 MIN 24 18 VO = –10V to +10V FREQUENCY RESPONSE Small-Signal Bandwidth Slew Rate Settling Time: 0.1% 0.01% Overload Recovery Time MAX RTO INPUT IMPEDANCE(2) Differential Common-Mode INPUT VOLTAGE RANGE Common-Mode Voltage Range Positive Negative Common-Mode Rejection Ratio INA157UA TYP (V+)–2 (V–)+2 –3dB ✽ ✽ ✽ ✽ ±0.05 ±10 ±0.001 ✽ ✽ (V+)–1.8 (V–)+1.6 ±60 500 4 14 2 3 3 10V Step, CL = 100pF 10V Step, CL = 100pF 50% Overdrive ±15 ±4 ±2.4 IO = 0mA –40 –55 –55 150 ±0.1 ✽ ±0.002 ✽ ✽ ✽ ✽ V V mA pF ✽ ✽ ✽ ✽ ✽ MHz V/µs µs µs µs ✽ ±18 ±2.9 ✽ +85 +125 +125 ✽ ✽ ✽ V/V % ppm/°C % of FS ✽ ✽ ✽ ✽ V V mA ✽ ✽ ✽ °C °C °C °C/W ✽Specifications the same as INA157U. NOTES: (1) Includes effects of amplifier’s input bias and offset currents. (2) Internal resistors are ratio matched but have ±20% absolute value. (3) Includes effects of amplifier’s input current noise and thermal noise contribution of resistor network. 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. ® INA157 2 ABSOLUTE MAXIMUM RATINGS(1) PIN CONFIGURATION TOP VIEW SO-8 Ref 1 8 NC –In 2 7 V+ +In 3 6 Output V– 4 5 Sense Supply Voltage, V+ to V– .................................................................... 40V Input Voltage Range .......................................................................... ±80V Output Short Circuit (to ground) ............................................. Continuous Operating Temperature .................................................. –55°C to +125°C Storage Temperature ..................................................... –55°C to +125°C Junction Temperature .................................................................... +150°C Lead Temperature (soldering, 10s) ............................................... +300°C NOTE: (1) Stresses above these ratings may cause permanent damage. Exposure to absolute maximum conditions for extended periods may degrade device reliability. ELECTROSTATIC DISCHARGE SENSITIVITY 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. NC = No Connection 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. PACKAGE/ORDERING INFORMATION PACKAGE PACKAGE DRAWING NUMBER(1) SPECIFIED TEMPERATURE RANGE PACKAGE MARKING ORDERING NUMBER(2) TRANSPORT MEDIA INA157U SO-8 Surface-Mount 182 –40°C to +85°C INA157U " " " " " INA157UA SO-8 Surface-Mount 182 –40°C to +85°C INA157UA " " " " " INA157U INA157U/2K5 INA157UA INA157UA/2K5 Rails Tape and Reel Rails Tape and Reel PRODUCT NOTES: (1) For detailed drawing and dimension table, please see end of data sheet, or Appendix C of Burr-Brown IC Data Book. (2) Models with a slash (/) are available only in Tape and Reel in the quantities indicated (e.g., /2K5 indicates 2500 devices per reel). Ordering 2500 pieces of “INA157U/2K5” will get a single 2500-piece Tape and Reel. For detailed Tape and Reel mechanical information, refer to Appendix B of Burr-Brown IC Data Book. ® 3 INA157 TYPICAL PERFORMANCE CURVES At TA = +25°C, VS = ±15V, and G = 1/2, unless otherwise noted. COMMON-MODE REJECTION RATIO vs FREQUENCY GAIN vs FREQUENCY 100 Common-Mode Rejection Ratio (dB) 10 Voltage Gain (dB) 0 –10 –20 80 60 RTO 40 –30 1k 10k 100k 1M 1k 10M 10k 100k 1M Frequency (Hz) Frequency (Hz) POWER SUPPLY REJECTION RATIO vs FREQUENCY MAXIMUM OUTPUT VOLTAGE vs FREQUENCY 120 40 100 80 Output Voltage (Vp-p) Power Supply Rejection (dB) RTO –PSRR 60 40 +PSRR 20 10 20 0 0 100 1k 10k 100k 1M 100 1k 10k 100k 1M Frequency (Hz) Frequency (Hz) INPUT COMMON-MODE VOLTAGE vs OUTPUT VOLTAGE TOTAL HARMONIC DISTORTION + NOISE vs FREQUENCY 80 10M 0.1 G = 1/2 VS = ±15V 60 VO = 5Vrms 40 THD+Noise (%) Common-Mode Voltage (V) 30 20 0 –20 0.010 RL = 100kΩ RL = 2kΩ 0.001 –40 –60 VREF = 0V RL = 2kΩ RL = 600Ω –80 0.0001 –20 –15 –10 –5 0 5 10 15 20 20 ® INA157 100 1k Frequency (Hz) Output Voltage (V) 4 10k 20k TYPICAL PERFORMANCE CURVES (CONT) At TA = +25°C, VS = ±15V, and G = 1/2, unless otherwise noted. QUIESCENT CURRENT vs TEMPERATURE SLEW RATE vs TEMPERATURE 4 16 3 14 Slew Rate (V/µs) Quiescent Current (mA) –SR 2 1 0 +SR 12 10 8 –75 –50 –25 0 25 50 75 100 125 –75 –50 –25 0 Temperature (°C) SHORT-CIRCUIT CURRENT vs TEMPERATURE 75 100 125 OUTPUT VOLTAGE SWING vs OUTPUT CURRENT 13 40 Output Voltage Swing (V) 60 Short-Circuit Current (mA) 50 14 80 +ISC 20 0 –20 –ISC –40 25 50 75 100 85°C 9 –9 85°C 125°C –10 –11 –12 –14 0 125°C 10 –80 –25 25°C 11 –13 –50 –55°C 12 –60 –75 125 25°C 0 ±20 ±40 ±60 Temperature (°C) Output Current (mA) OUTPUT VOLTAGE NOISE SPECTRAL DENSITY vs FREQUENCY OUTPUT NOISE VOLTAGE vs NOISE BANDWIDTH 10k –55°C ±80 100 Noise Voltage (µVrms) Voltage Noise (nV/√Hz) 25 Temperature (°C) 1k 100 10 10 1 0.1 1 10 100 1k 10k 100k 1M 1 Frequency (Hz) 10 100 1k 10k 100k Frequency (Hz) ® 5 INA157 TYPICAL PERFORMANCE CURVES (CONT) At TA = +25°C, VS = ±15V, and G = 1/2, unless otherwise noted. OFFSET VOLTAGE PRODUCTION DISTRIBUTION OFFSET VOLTAGE DRIFT PRODUCTION DISTRIBUTION 35 25 20 Percent of Units (%) 30 25 20 15 10 15 10 5 5 0 –1000 –900 –800 –700 –600 –500 –400 –300 –200 –100 0 100 200 300 400 500 600 700 800 900 1000 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Offset Voltage Drift (µV/°C) Offset Voltage (µV) SMALL-SIGNAL STEP RESPONSE LARGE-SIGNAL STEP RESPONSE CL = 500pF CL = 100pF 5V/div 50mV/div CL = 500pF 1µs/div 1µs/div SMALL-SIGNAL OVERSHOOT vs LOAD CAPACITANCE 70 60 50 Overshoot (%) Percent of Units (%) Typical production distribution of packaged units. Typical Production Distribution of Packaged Units. 40 30 20 RL = 2kΩ 100mV Step 10 0 0 200 400 600 800 Load Capacitance (pF) ® INA157 6 1000 1200 INPUT VOLTAGE RANGE APPLICATIONS INFORMATION The INA157 can accurately measure differential signals that are above the positive or negative power supply rail. In a gain of 1/2, the linear common-mode range extends from 3•(V+) – 7.5V to 3•(V–) +7.5V. See the Typical Performance Curve, “Input Common-Mode Range vs Output Voltage.” The INA157 is a difference amplifier suitable for a wide range of general-purpose applications. Figure 1 shows the basic G = 1/2 configuration. The input and feedback resistors can be reversed to achieve G = 2, as shown in Figure 2. For applications requiring G = 1, the INA154 is recommended. Decoupling capacitors are strongly recommended for applications with noisy or high impedance power supplies. The capacitors should be placed close to the device pins as shown in Figure 1. OFFSET VOLTAGE TRIM The INA157 is laser trimmed for low offset voltage and drift. Most applications require no external offset adjustment. Figure 3 shows an optional circuit for trimming the output offset voltage. The output is referred to the output reference terminal (pin 1), which is normally grounded. A voltage applied to the Ref terminal will be summed with the output signal. This can be used to null offset voltage as shown in Figure 3. The source impedance of a signal applied to the Ref terminal should be less than 10Ω to maintain good common-mode rejection. As shown in Figure 1, the output is referred to the reference terminal (pin 1). A voltage applied to this pin will be summed with the output signal. The differential input signal is connected to pins 2 and 3. The source impedances connected to the inputs must be nearly equal to assure good common-mode rejection. A 5Ω mismatch in source impedance will degrade the common-mode rejection of a typical device to approximately 77dB (RTO). If the source has a known impedance mismatch, an additional resistor in series with the opposite input can be used to preserve good common-mode rejection. INA157 –In V2 V+ V– 5 R2 6kΩ R1 12kΩ 2 1µF 1µF 6 7 4 INA157 –In V2 2 R1 12kΩ +In R2 6kΩ V3 1 R4 6kΩ 3 Ref V3 3 RL R3 12kΩ R4 6kΩ VO = 2 (V3 – V2) R3 12kΩ 5 6 +In RL FIGURE 2. G = 2 Differential Amplifier. VO = 1/2 (V3 – V2) G = 1/2 INA157 1 Ref 2 V2 R1 12kΩ R2 6kΩ FIGURE 1. G = 1/2 Differential Amplifier (basic power supply and signal connections). 5 6 20Ω OPERATING VOLTAGE V3 The INA157 operates from ±4V to ±18V supplies with excellent performance. Most behavior remains unchanged throughout the full operating voltage range. Parameters which vary significantly with operating voltage are shown in the Typical Performance Curves. 3 R3 12kΩ R4 6kΩ VO = 1/2 (V3 – V2) Offset Adjustment Range = ±1mV VO 1 +15V 250kΩ 100kΩ 10Ω –15V FIGURE 3. Offset Adjustment. ® 7 INA157 INA157 6kΩ 2 5 –In V1 5 BUF634 V0 = 2V1 + V2 12kΩ V2 2 6 6 6kΩ 1 BUF634 inside feedback loop contributes no error. INA157 12kΩ +In 3 1 (Low IQ mode) VO RL 3 FIGURE 4. Precision Summing Amplifier. FIGURE 6. Boosting Output Current. The difference amplifier is a highly versatile building block that is useful in a wide variety of applications. See the INA105 data sheet for additional applications ideas, including: V1 INA157 –In A1 2 5 • Current Receiver with Compliance to Rails R2 6 R1 VO R2 • Precision Average Value Amplifier • Precision Bipolar Offsetting 1 3 V2 • ±10V Precision Voltage Reference • ±5V Precision Voltage Reference • Precision Summing Amplifier with Gain • Instrumentation Amplifier Guard Drive Generator A2 +In • Precision Summing Instrumentation Amplifier • Precision Absolute Value Buffer VO = (1 + 2R2/R1) (V2 –V1) • Precision Voltage-to-Current Converter with Differential Inputs • Differential Input Voltage-to-Current Converter for Low IOUT The INA157 can be combined with op amps to form a complete instrumentation amplifier with specialized performance characteristics. BurrBrown offers many complete high performance IAs. Products with related performances are shown at the right. FEATURE SIMILIAR COMPLETE BURR-BROWN IAs Low Noise Ultra Low Bias Current (fA) Low Offset Drift, Low Noise FET Input (pA) INA103 INA116 INA114, INA128 INA111, INA121 A1, A2 OPA227 OPA129 OPA277 OPA2134 • Isolating Current Source • Differential Output Difference Amplifier • Isolating Current Source with Buffering Amplifier for Greater Accuracy • Window Comparator with Window Span and Window Center Inputs • Precision Voltage-Controlled Current Source with Buffered Differential Inputs and Gain • Digitally Controlled Gain of ±1 Amplifier FIGURE 5. Precision Instrumentation Amplifier. ® INA157 8