® INA103 INA 103 INA 103 Low Noise, Low Distortion INSTRUMENTATION AMPLIFIER FEATURES APPLICATIONS ● LOW NOISE: 1nV/√Hz ● LOW THD+N: 0.0009% at 1kHz, G = 100 ● HIGH GBW: 100MHz at G = 1000 ● HIGH QUALITY MICROPHONE PREAMPS (REPLACES TRANSFORMERS) ● MOVING-COIL PREAMPLIFIERS ● WIDE SUPPLY RANGE: ±9V to ±25V ● HIGH CMRR: >100dB ● BUILT-IN GAIN SETTING RESISTORS: G = 1, 100 ● UPGRADES AD625 ● DIFFERENTIAL RECEIVERS ● AMPLIFICATION OF SIGNALS FROM: Strain Gages (Weigh Scale Applications) Thermocouples Bridge Transducers DESCRIPTION The INA103 is a very low noise, low distortion monolithic instrumentation amplifier. Its current-feedback circuitry achieves very wide bandwidth and excellent dynamic response. It is ideal for low-level audio signals such as balanced low-impedance microphones. The INA103 provides near-theoretical limit noise performance for 200Ω source impedances. Many industrial applications also benefit from its low noise and wide bandwidth. The INA103 is available in 16-pin plastic DIP and SOL-16 surface-mount packages. Commercial and Industrial temperature range models are available. Unique distortion cancellation circuitry reduces distortion to extremely low levels, even in high gain. Its balanced input, low noise and low distortion provide superior performance compared to transformer-coupled microphone amplifiers used in professional audio equipment. The INA103’s wide supply voltage (±9 to ±25V) and high output current drive allow its use in high-level audio stages as well. A copper lead frame in the plastic DIP assures excellent thermal performance. –Gain Drive 12 –Input 16 –Gain Sense 15 Offset Offset Null Null 3 4 6kΩ + A1 – 3kΩ 6kΩ 11 Sense –RG 13 – 60.6Ω G = 100 14 +RG 6 +Gain Sense 2 +Input 1 + 3kΩ 6kΩ – A3 10 Output 7 Ref 6kΩ A2 + 5 9 8 +Gain Drive V+ 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 ® © 1990 Burr-Brown Corporation PDS-1016H 1 INA103 Printed in U.S.A. March, 1998 SPECIFICATIONS All specifications at TA = +25°C, VS = ±15V and RL = 2kΩ, unless otherwise noted. INA103KP, KU PARAMETER CONDITIONS GAIN Range of Gain Gain Equation (1) Gain Error, DC G = 1 G = 100 Equation Gain Temp. Co. G = 1 G = 100 Equation Nonlinearity, DC G = 1 G = 100 OUTPUT Voltage, RL = 600Ω RL = 600Ω Current Short Circuit Current Capacitive Load Stability INPUT OFFSET VOLTAGE Initial Offset RTI (3) (KU Grade) vs Temp G = 1 to 1000 G = 1000 vs Supply INPUT BIAS CURRENT Initial Bias Current vs Temp Initial Offset Current vs Temp MIN 1 G = 1 + 6kΩ/RG 0.005 0.07 0.05 10 25 25 0.0003 0.0006 ±10V Output ±10V Output ±10V Output ±11.5 ±20 ±40 TA = TMIN to TMAX VS = ±25, TA = 25°C TA = TMIN to TMAX INPUT NOISE Voltage (5) 10Hz 100Hz 1kHz Current, 1kHz MAX UNITS 1000 V/V V/V % % % ppm/°C ppm/°C ppm/°C % of FS(2) % of FS 0.05 0.25 0.01 0.01 ±12 ±21 V V mA mA nF ±70 10 (30 + 1200/G) (250+ 5000/G) TA = TMIN to TMAX TA = TMIN to T MAX ±9V to ±25V 1 + 20/G TA = TMIN to TMAX TA = TMIN to TMAX INPUT IMPEDANCE Differential Mode Common-Mode INPUT VOLTAGE RANGE Common-Mode Range (4) CMR G=1 G = 100 TYP 0.2 + 8/G 4 + 60/G 2.5 15 0.04 0.5 12 1 µV µV µV/°C µV/°C µV/V µA nA/°C µA nA/°C 60 || 2 60 || 5 MΩ || pF MΩ || pF ±11 ±12 V 72 100 86 125 dB dB 2 1.2 1 2 nV/√Hz nV/√Hz nV/√Hz pA/√Hz 1kHz 20Hz-20kHz 65 –100 nV/√Hz dBu Small Signal Small Signal G=1 6 800 MHz kHz 240 15 0.0009 kHz V/µs % VO = 20V Step 1.7 1.5 µs µs VO = 20V Step 2 3.5 1 µs µs µs DC to 60Hz DC to 60Hz RS = 0Ω OUTPUT NOISE Voltage A Weighted, 20Hz-20kHz DYNAMIC RESPONSE –3dB Bandwidth: G = 1 G = 100 Full Power Bandwidth VOUT = ±10V, RL = 600Ω Slew Rate THD + Noise Settling Time 0.1% G=1 G = 100 Settling Time 0.01% G=1 G = 100 Overload Recovery (6) G = 1 to 500 G = 100, f = 1kHz 50% Overdrive NOTES: (1) Gains other than 1 and 100 can be set by adding an external resistor, RG between pins 2 and 15. Gain accuracy is a function of RG. (2) FS = Full Scale. (3) Adjustable to zero. (4) VO = 0V, see Typical Curves for VCM vs VO. (5) VNOISE RTI = √V2N INPUT + (VN OUTPUT/Gain)2 + 4KTRG. See Typical Curves. (6) Time required for output to return from saturation to linear operation following the removal of an input overdrive voltage. ® INA103 2 SPECIFICATIONS (CONT) All specifications at TA = +25°C, VS = ±15V and RL = 2kΩ, unless otherwise noted. INA103KP, KU PARAMETER CONDITIONS MIN POWER SUPPLY Rated Voltage Voltage Range Quiescent Current ±9 TYP ±15 9 TEMPERATURE RANGE Specification Operation Storage Thermal Resistance, θJA 0 –40 –40 Top View (1) 16 – Input 2 15 – Gain Sense + Offset Null 3 14 G = 100 – Offset Null 4 13 –RG + Gain Drive 5 12 – Gain Drive +RG 6 11 Sense Ref 7 10 Output V– 8 9 V+ + Gain Sense ±25 12.5 V V mA +70 +85 +100 Any 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 published specifications. ABSOLUTE MAXIMUM RATINGS(1) Power Supply Voltage ....................................................................... ±25V Input Voltage Range, Continuous ....................................................... ±VS Operating Temperature Range: ........................................ –40°C to +85°C Storage Temperature Range: ........................................... –40°C to +85°C Junction Temperature: P, U Package .............................................................................. +125°C Lead Temperature (soldering, 10s) ............................................... +300°C Output Short Circuit to Common ............................................. Continuous NOTE: (1) Pin 1 Marking—SOL-16 Package PACKAGE/ORDERING INFORMATION PRODUCT PACKAGE PACKAGE DRAWING NUMBER(1) INA103KP INA103KU Plastic DIP SOL-16 180 211 °C °C °C °C/W ELECTROSTATIC DISCHARGE SENSITIVITY DIP or SOIC 1 UNITS 100 PIN CONFIGURATION + Input MAX TEMPERATURE RANGE 0°C to +70°C 0°C to +70°C NOTE: (1) Stresses above these ratings may cause permanent damage. NOTE: (1) For detailed drawing and dimension table, please see end of data sheet, or Appendix C of Burr-Brown IC Data Book. 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. ® 3 INA103 TYPICAL PERFORMANCE CURVES At TA = +25°C, VS = ±15V, unless otherwise noted. OUTPUT SWING vs SUPPLY ±25 ±20 ±20 Output Voltage (V) Input Voltage Range (V) INPUT VOLTAGE RANGE vs SUPPLY ±25 ±15 ±10 ±15 ±10 ±5 ±5 ±5 ±10 ±15 ±20 ±25 ±5 ±10 Power Supply Voltage (V) MAX COMMON-MODE VOLTAGE vs OUTPUT VOLTAGE ±20 ±25 OUTPUT SWING vs LOAD RESISTANCE 22 ±16 16.5 V S = ±25V Output Voltage (V) Common-Mode Voltage (V) ±15 Power Supply Voltage (V) 11 V S = ±15V 5.5 ±12 ±8 ±4 ±0 0 5.5 11 16.5 22 0 200 Output Voltage (V) 400 600 800 1k Load Resistance (Ω ) OFFSET VOLTAGE vs TIME FROM POWER UP (G = 100) INPUT BIAS CURRENT vs SUPPLY 2.60 20 Input Bias Current (µA) Change In VOSI (µV) 2.55 10 0 –10 2.50 2.45 2.40 2.35 2.30 2.25 –20 0 1 2 3 4 5 9 Time (min) 15 20 Power Supply Voltage (±V) ® INA103 10 4 25 TYPICAL PERFORMANCE CURVES (CONT) At TA = +25°C, VS = ±15V, unless otherwise noted. SMALL SIGNAL TRANSIENT RESPONSE (G = 1) INPUT BIAS CURRENT vs TEMPERATURE Output Voltage (V) 5 4 3 2 1 –55 0 50 100 Time (µs) 125 Temperature (°C) LARGE SIGNAL TRANSIENT RESPONSE (G = 1) Output Voltage (V) SMALL SIGNAL TRANSIENT RESPONSE (G = 100) Output Voltage (V) Time (µs) Time (µs) SETTLING TIME vs GAIN (0.1%, 20V STEP) LARGE SIGNAL TRANSIENT RESPONSE (G = 100) 10 Settling Time (µs) 8 Output Voltage (V) Input Bias Current (µA) 6 6 4 2 0 1 Time (µs) 10 100 1000 Gain ® 5 INA103 TYPICAL PERFORMANCE CURVES (CONT) At TA = +25°C, VS = ±15V, unless otherwise noted. SETTLING TIME vs GAIN (0.01%, 20V STEP) SMALL-SIGNAL FREQUENCY RESPONSE 70 60 8 50 40 6 30 20 10 Gain (dB) Settling Time (µs) 10 4 G = 1000 G = 100 G = 10 0 –10 G=1 –20 –30 2 –40 –50 0 1 10 100 1000 10 100 1k 10k Gain NOISE VOLTAGE (RTI) vs FREQUENCY 10M CMR vs FREQUENCY 100 Common-Mode Rejection (dB) Noise (RTI) (nV/ √ Hz) 1M 140 1k G=1 G = 10 10 G = 500 G = 1000 G = 100 120 G= 100 0 100 G= 80 G= 60 G= 40 G= 500 100 10 1 20 0 1 10 100 1k 10k 10 100 1k 10k 100k Frequency (Hz) Frequency (Hz) THD + N vs FREQUENCY V+ POWER SUPPLY REJECTION vs FREQUENCY 1M 140 1 120 G = 100 G = 10 100 G=1 Power Supply Rejection (dB) VOUT = +18dBu 0.1 THD + N (%) 100k Frequency (Hz) G = 1000 0.010 G=1 0.001 G = 100 G = 10 0.0001 G = 1000 80 60 40 20 0 10 100 1k 10k 20k 1 Frequency (Hz) 100 1k Frequency (Hz) ® INA103 10 6 10k 100k 1M TYPICAL PERFORMANCE CURVES (CONT) At TA = +25°C, VS = ±15V, unless otherwise noted. V– POWER SUPPLY REJECTION vs FREQUENCY THD + N vs LEVEL 1 G = 100, 1000 f = 1kHz 120 G = 10 100 0.1 G=1 THD + N (%) Power Supply Rejection (dB) 140 80 60 0.010 40 G=1 20 0.001 0 0.0005 1 10 100 1k 10k 100k 1M –60 –45 –30 Frequency (Hz) 15 5 G=1 V OUT = 20Vp-p f = 1kHz 1 0.01 CCIF IMD (%) THD + N (%) 0 CCIF IMD vs AMPLITUDE THD + N vs LOAD 0.1 0.001 G = 1000 0.1 G = 100 0.010 G=1 G = 10 0.001 0.0001 0.0001 200 400 600 800 –60 1k –50 –40 RLOAD (Ω ) –30 –20 –10 0 10 20 10 20 Output Amplitude (dBu) CCIF IMD vs FREQUENCY SMPTE IMD vs AMPLITUDE 5 5 1 1 SMPTE IMD (%) CCIF IMD (%) –15 Output Amplitude (dBu) 0.1 G = 1000 0.010 G = 1000 0.1 G = 100 G=1 0.010 G = 100 0.001 G = 10 G=1 2k G = 10 0.001 0.0005 0.0001 10k 20k –60 Frequency (Hz) –50 –40 –30 –20 –10 0 Output Amplitude (dBu) ® 7 INA103 TYPICAL PERFORMANCE CURVES (CONT) At TA = +25°C, VS = ±15V unless, otherwise noted. CURRENT NOISE SPECTRAL DENSITY SMPTE IMD vs FREQUENCY 100 Current Noise Density (pA/ Hz) 5 SMPTE IMD (%) 1 0.1 G = 1000 0.010 G = 100 G=1 G = 10 0.001 0.0005 10 1 2k 10k 1 20k 10 100 1k 10k Frequency (Hz) Frequency (Hz) APPLICATIONS INFORMATION useful if various input sources are connected to the INA103. Although not shown in other figures, this network can be used, if needed, with all applications shown. Figure 1 shows the basic connections required for operation. Power supplies should be bypassed with 1µF tantalum capacitors near the device pins. The output Sense (pin 11) and output Reference (pin 7) should be low impedance connections. Resistance of a few ohms in series with these connections will degrade the common-mode rejection of the amplifier. To avoid oscillations, make short, direct connection to the gain set resistor and gain sense connections. Avoid running output signals near these sensitive input nodes. GAIN SELECTION Gains of 1 or 100V/V can be set without external resistors. For G = 1V/V (unity gain) leave pin 14 open (no connection)—see Figure 4. For G = 100V/V, connect pin 14 to pin 6—see Figure 5. Gain can also be accurately set with a single external resistor as shown in Figure 1. The two internal feedback resistors are laser-trimmed to 3kΩ within approximately ±0.1%. The temperature coefficient of these resistors is approximately 50ppm/˚C. Gain using an external RG resistor is— 6kΩ G=1+ RG INPUT CONSIDERATIONS Certain source impedances can cause the INA103 to oscillate. This depends on circuit layout and source or cable characteristics connected to the input. An input network consisting of a small inductor and resistor (Figure 2) can greatly reduce the tendancy to oscillate. This is especially ® INA103 8 V+ 1µF Tantalum + 50Ω 9 16 16 1.2µH 15 – V IN RG + 13 11 INA103 14 VO = G • VIN 10 11 INA103 7 6 7 RL VOUT 2 1.2µH 1 8 1 + V– NOTES: (1) No RG required for G = 1. See gain-set connections in Figure 4. (2) RG for G = 100 is internal. See gain-set connection in Figure 5. GAIN GAIN (dB) RG (Ω) 1 3.16 10 31.6 100 316 1000 0 10 20 30 40 50 60 Note 1 2774 667 196 60.6(2) 19 6 50Ω FIGURE 2. Input Stabilization Network. Offset voltage can be trimmed with the optional circuit shown in Figure 3. This offset trim circuit primarily adjusts the output stage offset, but also has a small effect on input stage offset. For a 1mV adjustment of the output voltage, the input stage offset is adjusted approximately 1µV. Use this adjustment to null the INA103’s offset voltage with zero differential input voltage. Do not use this adjustment to null offset produced by a sensor, or offset produced by subsequent stages, since this will increase temperature drift. FIGURE 1. Basic Circuit Configuration. Accuracy and TCR of the external RG will also contribute to gain error and temperature drift. These effects can be directly inferred from the gain equation. Connections available on A1 and A2 allow external resistors to be substituted for the internal 3kΩ feedback resistors. A precision resistor network can be used for very accurate and stable gains. To preserve the low noise of the INA103, the value of external feedback resistors should be kept low. Increasing the feedback resistors to 20kΩ would increase noise of the INA103 to approximately 1.5nV/√Hz. Due to the current-feedback input circuitry, bandwidth would also be reduced. To offset the output voltage without affecting drift, use the circuit shown in Figure 4. The voltage applied to pin 7 is summed at the output. The op amp connected as a buffer provides a low impedance at pin 7 to assure good commonmode rejection. Figure 5 shows a method to trim offset voltage in ACcoupled applications. A nearly constant and equal input bias current of approximately 2.5µA flows into both input terminals. A variable input trim voltage is created by adjusting the balance of the two input bias return resistances through which the input bias currents must flow. NOISE PERFORMANCE The INA103 provides very low noise with low source impedance. Its 1nV/√Hz voltage noise delivers near theoretical noise performance with a source impedance of 200Ω. Relatively high input stage current is used to achieve this low noise. This results in relatively high input bias current and input current noise. As a result, the INA103 may not provide best noise performance with source impedances greater than 10kΩ. For source impedance greater than 10kΩ, consider the INA114 (excellent for precise DC applications), or the INA111 FET-input IA for high speed applications. V– 10kΩ 16 6kΩ G = 1 + —– RG 3 15 4 13 ∆V IN RG OFFSET ADJUSTMENT Offset voltage of the INA103 has two components: input stage offset voltage is produced by A1 and A2; and, output stage offset is produced by A3. Both input and output stage offset are laser trimmed and may not need adjustment in many applications. 14 11 10 INA103 VOUT 7 6 2 1 Offset Adjust Range = ±250mV. RTI FIGURE 3. Offset Adjustment Circuit. ® 9 INA103 OUTPUT SENSE An output sense terminal allows greater gain accuracy in driving the load. By connecting the sense connection at the load, I•R voltage loss to the load is included inside the feedback loop. Current drive can be increased by connecting a current booster inside the feedback loop as shown in Figure 11. Figure 6 shows an active control loop that adjusts the output offset voltage to zero. A2, R, and C form an integrator that produces an offsetting voltage applied to one input of the INA103. This produces a –6dB/octave low frequency rolloff like the capacitor input coupling in Figure 5. COMMON-MODE INPUT RANGE For proper operation, the combined differential input signal and common-mode input voltage must not cause the input amplifiers to exceed their output swing limits. The linear input range is shown in the typical performance curve “Maximum Common-Mode Voltage vs Output Voltage.” For a given total gain, the input common-mode range can be increased by reducing the input stage gain and increasing the output stage gain with the circuit shown in Figure 7. IB– ≈ IB+ ≈ 2.5µA 16 Gain = 1V/V (0dB) 15 –In 13 11 INA103 ∆ VIN 14 IB– VOUT 10 Gain = 100V/V (40dB) 16 15 11 13 V+ 10 INA103 14 7 100µA(1) 6 VOUT 6 2 OPA27 1 – 2 IB+ 150Ω + 1 10kΩ +In (1) 50kΩ 150Ω Offset Adjustment Range = ±15mV 50kΩ 100µA(1) 100kΩ FIGURE 4. Output Offsetting. (1) NOTE: (1) 50k Ω R, 100kΩ pot is max recommended value. Use smaller values in this ratio if possible. FIGURE 5. Input Offset Adjustment for AC-Coupled Inputs. Gain = 100V/V (40dB) 16 –In 15 10 INA103 14 6 C 1µF 1 (1) 100kΩ (1) 10kΩ A2 2kΩ – + 1/2 OPA1013 NOTE: (1) 100kΩ is max recommended value. Use smaller value if possible. FIGURE 6. Automatic DC Restoration. ® 10 VOUT R 100kΩ 7 2 +In f–3dB = 11 13 INA103 (1) V– NOTE: (1) 1/2 REF200 100kΩ 7 Gain 12π RC RF 16 R1 15 16 13 11 INA103 ∆ VIN 14 R2 15 10 VOUT 7 6 ∆V IN RG 11 10 INA103 14 7 R3 2 12 13 VOUT 6 5 1 2 G = 1+ 1 Output Stage Gain = OUTPUT STAGE GAIN R1 and R3 (kΩ) R2 (Ω) 2 5 10 1k 1.2k 1.2k 2.4k 632Ω 273Ω (R2 || 12k) + R1 + R3 (R2 || 12k) 2RF RG RF RF > 10kΩ can increase noise and reduce bandwidth—see text. NOTE: AD625 equivalent pinout. FIGURE 7. Gain Adjustment of Output Stage. FIGURE 8. Use of External Resistors for Gain Set. (b) INA103 G = 1, VIN = ±15V, RL = 600Ω (a) AD625 G = 1, VIN = ±15V, RL = 600Ω A common problem with many IC op amps and instrumentation amplifiers is shown in (a). Here, the amplifier’s input is driven beyond its linear common-mode range, forcing the output of the amplifier into the supply rails. The output then “folds back”, i.e., a more positive input voltage now causes the output of the amplifier to go negative. The INA103 has protection circuitry to prevent fold-back, and as shown in (b), limits cleanly. FIGURE 9. INA103 Overload Condition Performance. Gain = 1V/V (0dB) 16 V+ 10Ω 15 16 15 13 ∆ VIN 14 11 INA103 10 13 7 ∆V IN RG 6 14 6 2 20Ω 1 MJ15011 CMR Trim 2 1 Introduces approximately +0.2% Gain Error. 11 10 INA103 100Ω VOUT (To headphone or speaker) 7 MJ15012 Buffer inside feedback loop V– FIGURE 10. Optional Circuit for Externally Trimming CMR. FIGURE 11. Increasing Output Circuit Drive. ® 11 INA103 47µF/63V 16 + 6.8kΩ +48V 15 2.2kΩ 20dB Pad 1 Phantom Power 240Ω cm 3 2 6.8kΩ 10Ω Gain Adjust 47kΩ 13 1kΩ 11 10 INA103 14 V OUT 7 6 100kΩ 1µF 2 47µF/63V 1 + – 2.2kΩ 20dB Pad OPA627 + 240Ω Output offset voltage control loop. FIGURE 12. Microphone Preamplifier with Provision for Phantom Power Microphones. 16 15 10kΩ 12 13 INA103 14 ∆V IN 10kΩ 11 10 VOUT 7 6 10kΩ 10kΩ 5 2 1 – 100Ω + Shield driver minimizes degradation of CMR due to distributed capacitance on the input lines. OPA602 FIGURE 13. Instrumentation Amplifier with Shield Driver. – + 16 OPA627 15 13 11 7 6 ∆V IN 2 1 Gain = 100V/V (40dB) – + OPA627 FIGURE 14. Gain-of-100 INA103 with FET Buffers. ® INA103 10 INA103 14 12 V OUT = 100 ∆V IN