® INA148 INA 148 For most current data sheet and other product information, visit www.burr-brown.com ±200V Common-Mode Voltage DIFFERENCE AMPLIFIER FEATURES DESCRIPTION ● HIGH COMMON-MODE VOLTAGE: +75V at VS = +5V ±200V at VS = ±15V ● FIXED DIFFERENTIAL GAIN = 1V/V ● LOW QUIESCENT CURRENT: 260µA ● WIDE SUPPLY RANGE: Single Supply: 2.7V to 36V Dual Supplies: ±1.35V to ±18V ● LOW GAIN ERROR: 0.075% max ● LOW NONLINEARITY: 0.002% max ● HIGH CMR: 86dB ● SO-8 PACKAGE The INA148 is a precision, low-power, unity-gain difference amplifier with a high common-mode input voltage range. It consists of a monolithic precision bipolar op amp with a thin-film resistor network. The on-chip resistors are laser trimmed for an accurate 1V/V differential gain and high common-mode rejection. Excellent temperature tracking of the resistor network maintains high gain accuracy and common-mode rejection over temperature. The INA148 will operate on single or dual supplies. The INA148 is available in a small SO-8 surfacemount package and it is specified for the –40°C to +85°C extended industrial temperature range. APPLICATIONS ● ● ● ● ● ● CURRENT SHUNT MEASUREMENTS DIFFERENTIAL SENSOR AMPLIFIERS LINE RECEIVERS BATTERY POWERED SYSTEMS AUTOMOTIVE INSTRUMENTATION STACKED CELL MONITORS – VIN 2 1MΩ 50kΩ 50kΩ 2.7778kΩ 6 A1 + VIN 3 VO 52.6316kΩ 1MΩ INA148 7 V+ 4 V– 1 Ref 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-1579A Printed in U.S.A.December, 1999 SPECIFICATIONS: VS = ±5V to ±15V Dual Supplies At TA = +25°C, RL = 10kΩ connected to ground and Ref pin connected to ground, unless otherwise noted. PARAMETER CONDITIONS OFFSET VOLTAGE (VO) Input Offset Voltage Drift vs Power Supply INPUT VOLTAGE RANGE Common-Mode Voltage Range Common-Mode Rejection MIN VOS ∆VOS/∆T PSRR VCM CMRR VS = ±15V, VCM = 0V VS = ±5V, VCM = 0V At TA = –40°C to +85°C VS = ±1.35V to ±18V, VCM = 0V + ) – (V – ) = 0V VS = ±15V, (VIN IN + – VS = ±5V, (VIN ) – (VIN ) = 0V VS = ±15V, VCM = –200V to +200V, RS = 0Ω VS = ±5V, VCM = –100V to +80V, RS = 0Ω ±1 ±1 ±10 ±50 –200 –100 70 70 ±5 ±5 mV mV µV°C µV/V ±400 +200 +80 86 86 V V dB dB 2 1 MΩ MΩ 17 880 µVp-p nV/√Hz VS = ±15V, VO = (V–) + 0.5 to (V+) – 1.5 VS = ±5V, VO = (V–) + 0.5 to (V+) – 1.5 1 ±0.01 ±3 ±0.001 ±0.001 VS = ±15V, 10V Step VS = ±15V, 10V Step VS = ±5V, 6V Step VS = ±5V, 6V Step 50% Input Overload 100 1 21 25 21 25 24 VO = (V–) + 0.5 to (V+) – 1.5 FREQUENCY RESPONSE Small Signal Bandwidth Slew Rate Settling Time: 0.1% 0.01% 0.1% 0.01% Overload Recovery OUTPUT (VO) Voltage Output RL = 100kΩ RL = 10kΩ (V–) + 0.25 (V–) + 0.5 ±0.075 ±10 ±0.002 V/V % ppm/°C % of FSR % of FSR kHz V/µs µs µs µs µs µs (V+) – 1 (V+) – 1.5 V V IO ±13 10 Continuous to Common Stable Operation POWER SUPPLY Operating Range, Dual Supplies Quiescent Current TEMPERATURE RANGE Specified Operating Storage Thermal Resistance UNITS RTI(1)(3) en GAIN Initial(1) Gain Error vs Temperature Nonlinearity Output Current Short-Circiuit Current Capacitive Load MAX RTI(1)(2) INPUT IMPEDANCE Differential Common Mode NOISE Voltage Noise, f = 0.1Hz to 10Hz Voltage Noise Density, f = 1kHz INA148UA TYP ±1.35 ±260 VIN = 0, IO = 0 –40 –55 –55 θJA SO-8 Surface Mount 150 mA nF ±18 ±300 V µA 85 125 125 °C °C °C °C/W – + and VIN ), gain = 1V/V (2) Input offset voltage specification includes effects of NOTES: (1) Overall difference amplifier configuration. Referred to input pins (VIN amplifier's input bias and offset currents. (3) Includes effects of input current noise and thermal noise contribution of resistor network. ® INA148 2 SPECIFICATIONS: VS = +5V Single Supply At TA = +25°C, RL = 10kΩ connected to VS/2 and Ref pin connected to VS/2, unless otherwise noted. PARAMETER OFFSET VOLTAGE (VO) Input Offset Voltage Drift vs Power Supply INPUT VOLTAGE RANGE Common-Mode Voltage Range Common-Mode Rejection CONDITIONS MIN VOS ∆VOS/∆T PSRR VCM CMRR ±1 ±10 ±50 VCM = VS/2 At TA = –40°C to +85°C VS = +2.7V to +36V, VCM = VS/2 + – (VIN ) – (VIN ) = 0V, VREF = 0.25V + ) – (V – ) = 0V, V (VIN IN REF = VS/2 VCM = –47.5V to +32.5V, RS = 0Ω –4 –47.5 70 ±5 mV µV°C µV/V ±400 +75 +32.5 86 V V dB 2 1 MΩ MΩ 17 880 µVp-p nV/√Hz VO = +0.5V to +3.5V 1 ±0.01 ±3 ±0.001 VS = +5V, 3V Step VS = +5V, 3V Step 50% Input Overload 100 1 21 25 13 VO = +0.5V to +3.5V FREQUENCY RESPONSE Small Signal Bandwidth Slew Rate Settling Time: 0.1% 0.01% Overload Recovery OUTPUT (VO) Voltage Output RL = 100kΩ RL = 10kΩ (V–) + 0.25 (V–) + 0.5 ±0.075 ±10 V/V % ppm/°C % of FSR kHz V/µs µs µs µs (V+) – 1 (V+) – 1.5 V V IO ±8 10 Continuous to Common Stable Operation POWER SUPPLY Operating Range, Single Supply Quiescent Current TEMPERATURE RANGE Specified Operating Storage Thermal Resistance UNITS RTI(1)(3) en GAIN Initial(1) Gain Error vs Temperature Nonlinearity Output Current Short-Circiuit Current Capacitive Load MAX RTI(1)(2) INPUT IMPEDANCE Differential Common Mode NOISE Voltage Noise, f = 0.1Hz to 10Hz Voltage Noise Density, f = 1kHz INA148UA TYP +2.7 VIN = 0, IO = 0 260 –40 –55 –55 θJA SO-8 Surface Mount mA nF +36 300 V µA 85 125 125 °C °C °C °C/W 150 + (VIN – VIN ), and gain = 1V/V (2) Input offset voltage specification includes effects of NOTES: (1) Overall difference amplifier configuration. Referred to input pins amplifier's input bias and offset currents. (3) Includes effects of input current noise and thermal noise contribution of resistor network. ® 3 INA148 ELECTROSTATIC DISCHARGE SENSITIVITY PIN CONFIGURATION TOP VIEW SO-8 Ref 1 8 NC –In 2 7 V+ +In 3 6 Out V– 4 5 NC 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. ABSOLUTE MAXIMUM RATINGS(1) Supply Voltage, V+ to V– .................................................................... 36V Signal Input Terminals, Continuous ................................................ ±200V Peak (0.1s) ............................................... ±500V Output Short Circuit to GND Duration .................................... 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. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those specified is not implied. PACKAGE/ORDERING INFORMATION PRODUCT PACKAGE PACKAGE DRAWING NUMBER INA148UA SO-8 182 –40°C to +85°C INA148UA " " " " " SPECIFIED TEMPERATURE RANGE PACKAGE MARKING ORDERING NUMBER(1) TRANSPORT MEDIA INA148UA INA148UA/2K5 Rails Tape and Reel NOTE: (1) 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 “INA148UA/2K5” will get a single 2500-piece Tape and Reel. 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. ® INA148 4 TYPICAL PERFORMANCE CURVES At TA = +25°C, VS = ±15V, RL = 10kΩ to common, and VREF = 0V, unless otherwise noted. COMMON-MODE REJECTION vs FREQUENCY GAIN vs FREQUENCY 5 100 VS= ±1.35V = VS = ±15V = VS = ±1.35V 0 VS = ±15V Voltage Gain (dB) Voltage Gain (dB) 80 –5 –10 –20 –25 60 40 20 –30 0 –35 10 100 10k 1k 100k 1M 10 100 90 PSR+ (VS = ±1.35V) PSR– (VS = ±18V) 60 PSR– (VS = ±1.35V) 50 40 30 20 10 1k 800 600 400 200 100 1 10 1k 100 10k 10 100K 100 1k 10k 100k Frequency (Hz) Frequency (Hz) VOLTAGE NOISE (RTI) 0.1Hz to 10Hz QUIESCENT CURRENT vs TEMPERATURE 290 280 VS = ±15V 270 260 IQ (µA) 5µV/div Power Supply Rejection (dB) Input Noise Spectral Density (nV/√Hz) PSR+ (VS = ±18V) 70 1M INPUT VOLTAGE NOISE SPECTRAL DENSITY POWER SUPPLY REJECTION vs FREQUENCY 80 100k Frequency (Hz) 110 100 10k 1k Frequency (Hz) 250 VS = ±2.5V 240 230 220 210 –60 –40 –20 1s/div 0 20 40 60 80 100 120 140 Temperature (°C) ® 5 INA148 TYPICAL PERFORMANCE CURVES (Cont.) At TA = +25°C, VS = ±15V, RL = 10kΩ to common, and VREF = 0V, unless otherwise noted. LARGE-SIGNAL STEP RESPONSE vs TEMPERATURE SHORT-CIRCUIT CURRENT vs TEMPERATURE 20 +SC 10 +125°C 5 +125°C –55°C 5V/div –55°C 0 –5 –10 –SC –15 –20 –60 –40 –20 20 0 40 80 60 100 120 140 Temperature (°C) 25µs/div OUTPUT VOLTAGE SWING vs RL LARGE-SIGNAL STEP RESPONSE (RL = 10kΩ, CL = 10pF) RL = 100kΩ RL = 1kΩ 5V/div 5V/div RL = 1kΩ RL = 10kΩ RL = 10kΩ RL = 100kΩ 1ms/div 25µs/div SMALL-SIGNAL STEP RESPONSE (RL = 10kΩ, CL = 10pF) LARGE-SIGNAL CAPACITIVE LOAD RESPONSE (CL = 1nF and 10nF) CL = 1nF CL = 10nF G = +1V/V VIN 5V/div 50mV/div Short-Circuit Current (mA) 15 10µs/div 100µs/div ® INA148 6 TYPICAL PERFORMANCE CURVES (Cont.) At TA = +25°C, VS = ±15V, RL = 10kΩ to common, and VREF = 0V, unless otherwise noted. OFFSET VOLTAGE PRODUCTION DISTRIBUTION OFFSET VOLTAGE PRODUCTION DISTRIBUTION 24 VS = ±15V Percent of Amplifiers (%) Percent of Amplifiers (%) 24 18 12 6 VS = ±2.5V 20 16 12 8 4 5.0 4.0 3.0 2.0 1.0 0.0 OFFSET VOLTAGE DRIFT PRODUCTION DISTRIBUTION OFFSET VOLTAGE DRIFT PRODUCTION DISTRIBUTION 20 20 VS = ±15V Percent of Amplifiers (%) 15 10 5 VS = ±2.5V 15 10 5 30.0 24.0 18.0 12.0 6.0 0.0 –6.0 –12.0 –30.0 30.0 24.0 12.0 6.0 0.0 –6.0 –12.0 –18.0 –24.0 –30.0 18.0 Offset Voltage Drift, RTI (µV/°C) Offset Voltage Drift, RTI (µV/°C) GAIN DRIFT PRODUCTION DISTRIBUTION GAIN DRIFT PRODUCTION DISTRIBUTION 40 –18.0 0 0 –24.0 40 Percent of Amplifiers (%) VS = ±15V 30 20 10 VS = ±2.5V 30 20 10 10.0 8.0 6.0 4.0 2.0 0.0 –2.0 –4.0 –10.0 10.0 8.0 6.0 4.0 2.0 0.0 –4.0 –6.0 –8.0 –10.0 –2.0 Gain Drift (ppm/°C) –8.0 0 0 –6.0 Percent of Amplifiers (%) –1.0 Offset Voltage, RTI (mV) Offset Voltage, RTI (mV) Percent of Amplifiers (%) –2.0 –3.0 –5.0 5.0 4.0 3.0 2.0 1.0 0.0 –1.0 –2.0 –3.0 –4.0 –5.0 –4.0 0 0 Gain Drift (ppm/°C) ® 7 INA148 TYPICAL PERFORMANCE CURVES (Cont.) At TA = +25°C, VS = ±15V, RL = 10kΩ to common, and VREF = 0V, unless otherwise noted. INVERTING INPUT 50% OVERLOAD RECOVERY TIME NON-INVERTING INPUT 50% OVERLOAD RECOVERY TIME VS = ±15V VIN VS = ±15V VIN+ 0V – VOUT 5V/div 5V/div VOUT 0V 0V 5µs/div 5µs/div APPLICATION INFORMATION capacitors should be connected as close to pins 4 and 7 as practicable. Ceramic or tantalum types are recommended for use as bypass capacitors. The INA148 is a unity gain difference amplifier with a high common-mode input voltage range. A basic diagram of the circuit and pin connections is shown in Figure 1. The input impedances are unusually high for a difference amplifier and this should be considered when routing input signal traces on a PC board. Avoid placing digital signal traces near the difference amplifier’s input traces to minimize noise pickup. To achieve its high common-mode voltage range, the INA148 features a precision laser-trimmed thin-film resistor network with a 20:1 input voltage divider ratio. High input voltages are thereby reduced in amplitude, allowing the internal op amp to “see” input voltages that are within its linear operating range. A “Tee” network in the op amp feedback network places the amplifier in a gain of 20V/V, thus restoring the circuit’s overall gain to unity (1V/V). OPERATING VOLTAGE The INA148 is specified for ±15V and ±5V dual supplies and +5V single supplies. The INA148 can be operated with single or dual supplies with excellent performance. The INA148 is fully characterized for supply voltages from ±1.35V to ±18V and over temperatures of –55ºC to +125 ºC. Parameters that vary significantly with operating voltage, load conditions, or temperature are shown in the Typical Performance Curves section. External voltages can be summed into the amplifier’s output by using the Ref pin, making the differential amplifier a highly versatile design tool. Voltages on the Ref pin will also influence the INA148’s common-mode voltage range. In accordance with good engineering practice for linear integrated circuits, the INA148’s power-supply bypass +VS 0.1µF 7 – VIN 2 1MΩ 50kΩ 50kΩ + – VO = (VIN – VIN ) 2.7778kΩ 6 A1 + VIN 3 1MΩ 52.6316kΩ INA148 4 1 0.1µF –VS FIGURE 1. Basic Circuit Connections. ® INA148 8 VO THE GAIN EQUATION An internal on-chip resistor network sets the overall differential gain of the INA148 to precisely 1V/V. It’s output is accordance with the equation: + – V– ) + V VOUT = (VIN IN REF OFFSET TRIM The INA148 is laser-trimmed for low offset voltage and drift. Most applications will require no external offset adjustment. Since a voltage applied to the reference (Ref) pin (pin 1) will be summed directly into the amplifier’s output signal, this technique can be used to null the amplifier’s input offset voltage. Figure 2 shows an optional circuit for trimming the offset voltage. To maintain high common-mode rejection (CMR), the source impedance of any signal applied to the Ref terminal should be very low (≤5Ω). A source impedance of only 10Ω at the Ref pin will reduce the INA148’s CMR to approximately 74dB. High CMR can be restored if a resistor is added in series with the amplifier’s positive input terminal (pin 3). This resistor should be 19 times the source impedance that drives the Ref pin. For example, if the Ref pin sees a source impedance of 10Ω, a resistor of 190Ω should be added in series with pin 3. (1) COMMON-MODE RANGE The 20:1 input resistor ratio of the INA148 provides an input common-mode range that extends well beyond its power supply rails. The exact input voltage range depends on the amplifier’s power-supply voltage and the voltage applied to the Ref terminal (pin 1). Typical input voltage ranges at different power supply voltages can be found in the applications circuits section. +VS 7 2 – VIN 1MΩ 50kΩ 50kΩ + – VO = (VIN – VIN ) + VREF 2.7778kΩ 6 A1 190Ω + VIN 3 52.6316kΩ 1MΩ INA148 VREF 1 4 ±15mV Offset Trim Range, RTI VO +15V 10kΩ 10kΩ –VS 10Ω –15V FIGURE 2. Optional Offset Trim Voltage. +15V 7 – VIN 2 1MΩ 50kΩ 50kΩ + – VO = (VIN – VIN ) + VREF 2.7778kΩ 6 A1 + VIN 3 VO 52.6316kΩ 1MΩ INA148 4 VREF 1 +15V –15V OPA237 ±15mV Offset Trim Range, RTI 100kΩ 100kΩ 100Ω –15V FIGURE 3. Preferred Offset Trim Circuit. ® 9 INA148 Preferably, the offset trim voltage applied to the Ref pin should be buffered with an amp such as an OPA237 (see Figure 3). In this case, the op amp output impedance is low enough that no external resistor is needed to maintain the INA148’s excellent CMR. Unless the shunt resistor is less than approximately 100Ω, an additional equal compensating resistor (RC) is recommended to maintain input balance and high CMR. Source impedances (or shunts) greater than 5kΩ are not recommended, even if they are “perfectly” compensated. This is because the internal resistor network is laser-trimmed for accurate voltage divider ratios, but not necessarily to absolute values. Input resistors are shown as 1MΩ, however, this is only their nominal value. INPUT IMPEDANCE The input resistor network determines the impedance of each of the INA148’s inputs. It is approximately 1MΩ. Unlike an instrumentation amplifier, signal source impedances at the two input terminals must be nearly equal to maintain good common-mode rejection. In practice, the input resistors’ absolute values may vary by as much as 30 percent. The two input resistors match to about 5 percent, so adding compensating resistors greater than 5kΩ can cause a serious mismatch in the resulting resistor network voltage divider ratios, thus degrading CMR. A mismatch between the two inputs’ source impedances will cause a differential amplifier’s common-mode rejection to be degraded. With a source impedance imbalance of only 500Ω, CMR can fall to approximately 66dB. Attempts to extend the INA148 input voltage range by adding external resistors is not recommended for the reasons just described in the last paragraph. CMR will suffer a serious degradation unless the resistors are carefully trimmed for CMR and gain. This is an iterative adjustment and can be tedious and time consuming. Figure 4 shows a common application—measuring power supply current through a shunt resistor (RS). A shunt resistor creates an unbalanced source resistance condition that can degrade a differential amplifier’s common mode rejection. +15V 7 LOAD 2 1MΩ 50kΩ 50kΩ VO = IL • RS IL 2.7778kΩ 6 A1 RS RC 3 VO 52.6316kΩ 1MΩ INA148 VCM 4 200V 1 –15V Make RC = RS if RS ≥ 100Ω FIGURE 4. Shunt-Resistor Current Measurement Circuit. +15V C1 4.7µF(1) 250V – VIN 7 2 1MΩ 50kΩ 50kΩ + – V– ) VO = (VIN IN 2.7778kΩ 6 VCM = 200Vpk C2 4.7µF(1) 250V + VIN A1 3 52.6316kΩ 1MΩ INA148 4 1 –15V NOTE: (1) Metallized polypropylene, ±5% tolerance. FIGURE 5. AC-Coupled Difference Amplifier. ® INA148 VO 10 Typical CMR: 50Hz = 59dB 60Hz = 61dB 400Hz = 78dB +VS fC ≅ 0.75 Hz HPF 7 – VIN 2 U1 1MΩ 50kΩ 50kΩ + – VO = (VIN – VIN ) + VREF 2.7778kΩ 6 VO A1 + VIN 3 52.6316kΩ 1MΩ 1MΩ INA148 1 4 0.22µF –VS +VS 7 U2: OPA132 for VS = ±5V to ±15V OPA340 for VS = ±2.5 2 6 U2 4 VREF 3 –VS FIGURE 6. Quasi-AC-Coupled Differential Amplifier. +5V 0.1µF 7 – VIN 2 1MΩ 50kΩ 50kΩ + – V – ) + 1.235V VO = (VIN IN 2.7778kΩ 6 VCM = –23V to +56V + VIN 3 VO A1 52.6316kΩ 1MΩ INA148 4 1 34kΩ 5Ω +5V 10µF + REF1004-1.2 FIGURE 7. Single-Supply Differential Amplifier. IC RS 0.01Ω + 0.1µF – 28V Supply 7 2 1MΩ 50kΩ 50kΩ 2.7778kΩ 6 VO = 1.235V + (IC • RS) A1 3 52.6316kΩ 1MΩ INA148 4 1 271kΩ 5Ω + 10µF REF1004-1.2 FIGURE 8. Battery Monitor Circuit. ® 11 INA148 0.47µF ceramic (all) RS 50mV shunt I 6 +15 +VISO VCM = ±200V max +VS IN5245 5 1kΩ C 200kΩ 0.1µF +VISO 2 O IN5245 +15V 7 –VISO 6 7 3 4 2 –15 DCP011515D 7 OPA277 +15V 1 2 1MΩ 50kΩ 50kΩ –VISO 2.7778kΩ 6 VO A1 ±50mV Input = ±10V Output 3 52.6316kΩ 1MΩ INA148 4 0.1µF 1 –15V FIGURE 9. 50mV Current Shunt Amplifier with ±200V Common-Mode Voltage Range. ® INA148 12