INA122UA

® INA INA122 122 INA 122 Single Supply, MicroPower INSTRUMENTATION AMPLIFIER FEATURES APPLICATIONS ● LOW QUIESCENT CURRENT: 60µA ● PORTABLE, BATTERY OPERATED SYSTEMS ● INDUSTRIAL SENSOR AMPLIFIER: Bridge, RTD, Thermocouple ● PHYSIOLOGICAL AMPLIFIER: ECG, EEG, EMG ● MULTI-CHANNEL DATA ACQUISITION ● WIDE POWER SUPPLY RANGE Single Supply: 2.2V to 36V Dual Supply: –0.9/+1.3V to ±18V ● COMMON-MODE RANGE TO (V–)–0.1V ● RAIL-TO-RAIL OUTPUT SWING ● LOW OFFSET VOLTAGE: 250µV max ● LOW OFFSET DRIFT: 3µV/°C max DESCRIPTION ● LOW NOISE: 60nV/√ Hz ● LOW INPUT BIAS CURRENT: 25nA max ● 8-PIN DIP AND SO-8 SURFACE-MOUNT The INA122 is a precision instrumentation amplifier for accurate, low noise differential signal acquisition. Its two-op-amp design provides excellent performance with very low quiescent current, and is ideal for portable instrumentation and data acquisition systems. The INA122 can be operated with single power supplies from 2.2V to 36V and quiescent current is a mere 60µA. It can also be operated from dual supplies. By utilizing an input level-shift network, input commonmode range extends to 0.1V below negative rail (single supply ground). V+ 7 INA122 3 + VIN 6 8 VO + – V–) G VO = (VIN IN 100kΩ 200k G=5+ RG 25kΩ RG 25kΩ A single external resistor sets gain from 5V/V to 10000V/V. Laser trimming provides very low offset voltage (250µV max), offset voltage drift (3µV/°C max) and excellent common-mode rejection. Package options include 8-pin plastic DIP and SO-8 surface-mount packages. Both are specified for the –40°C to +85°C extended industrial temperature range. 1 – VIN 2 100kΩ 5 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/ • FAXLine: (800) 548-6133 (US/Canada Only) • Cable: BBRCORP • Telex: 066-6491 • FAX: (520) 889-1510 • Immediate Product Info: (800) 548-6132 ©1997 Burr-Brown Corporation SBOS069 PDS-1388B Printed in U.S.A. October, 1997 SPECIFICATIONS At TA = +25°C, VS = +5V, RL = 20kΩ connected to VS/2, unless otherwise noted. INA122P, U PARAMETER CONDITIONS INPUT Offset Voltage, RTI vs Temperature vs Power Supply (PSRR) Input Impedance Safe Input Voltage MIN VS = +2.2V to +36V RS = 0 RS = 10kΩ Common-Mode Voltage Range Common-Mode Rejection VCM = 0V to 3.4V (V–)–0.3 (V–)–40 0 83 INPUT BIAS CURRENT vs Temperature Offset Current vs Temperature GAIN Gain Equation Gain Error vs Temperature Gain Error vs Temperature Nonlinearity MAX ±100 ±1 10 1010 || 3 ±250 ±3 30 (V+)+0.3 (V+)+40 3.4 96 –10 ±40 ±1 ±40 NOISE (RTI) Voltage Noise, f = 1kHz f = 100Hz f = 10Hz fB = 0.1Hz to 10Hz Current Noise, f = 1kHz fB = 0.1Hz to 10Hz FREQUENCY RESPONSE Bandwidth, –3dB Slew Rate Settling Time, 0.01% Overload Recovery POWER SUPPLY Voltage Range, Single Supply Dual Supplies Current TEMPERATURE RANGE Specification Operation Storage Thermal Resistance, θJA 8-Pin DIP SO-8 Surface-Mount MIN ✻ ✻ ✻ 76 ±2 ✻ ✻ (V+)–0.1 (V+)–0.05 (V–)+0.15 (V–)+0.1 +3/–30 1 G=5 G = 100 G = 500 120 5 0.9 +0.08/–0.16 350 450 1.8 3 G=5 G = 100 G = 500 50% Input Overload +2.2 –0.9/+1.3 IO = 0 +5 60 –40 –55 –55 150 150 MAX UNITS ±150 ✻ ✻ ✻ ±500 ±5 100 µV µV/°C µV/V Ω || pF V V V dB ✻ ✻ ✻ 90 ✻ ✻ ✻ ✻ ✻ ✻ ✻ 60 100 110 2 80 2 VS = ±15V VS = ±15V Short-Circuit to Ground TYP ✻ ✻ ✻ ✻ –25 G = 5 to 10k G = 5 + 200kΩ/RG ±0.05 ±0.1 5 10 ±0.3 ±0.5 ±25 ±100 ±0.005 ±0.012 G=5 G=5 G = 100 G = 100 G = 100, VO = –14.85V to +14.9V OUTPUT Voltage, Positive Negative Short-Circuit Current Capacitive Load Drive INA122PA, UA TYP +36 ±18 85 ✻ ✻ +85 +85 +125 ✻ ✻ ✻ –50 ±5 ±0.15 ✻ ±1 ✻ ±0.024 nA pA/°C nA pA/°C V/V V/V % ppm/°C % ppm/°C % ✻ ✻ ✻ ✻ ✻ ✻ nV/√Hz nV/√Hz nV/√Hz µVp-p fA/√Hz pAp-p ✻ ✻ ✻ ✻ V V mA nF ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ kHz kHz kHz V/µs µs µs ms µs ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ V V µA ✻ ✻ ✻ °C °C °C °C/W °C/W ✻ Specification same as INA122P, INA122U. 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. ® INA122 2 ELECTROSTATIC DISCHARGE SENSITIVITY PIN CONFIGURATION Top View 8-Pin DIP, SO-8 RG 1 8 RG V– IN 2 7 V+ + VIN 3 6 VO V– 4 5 Ref 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, Voltage(2) ....................... (V–)–0.3V to (V+)+0.3V Current(2) ...................................................... 5mA Output Short Circuit ................................................................. Continuous Operating Temperature ................................................. –40°C to +125°C Storage Temperature ..................................................... –55°C to +125°C Lead Temperature (soldering, 10s) ............................................... +300°C NOTES: (1) Stresses above these ratings may cause permanent damage. (2) Input terminals are internally diode-clamped to the power supply rails. Input signals that can exceed the supply rails by more than 0.3V should be current-limited to 5mA or less. PACKAGE INFORMATION PRODUCT PACKAGE PACKAGE DRAWING NUMBER(1) INA122PA INA122P 8-Pin DIP 8-Pin DIP 006 006 INA122UA INA122U SO-8 Surface Mount SO-8 Surface Mount 182 182 NOTE: (1) For detailed drawing and dimension table, see end of data sheet, or Appendix C of Burr-Brown IC Data Book. ® 3 INA122 TYPICAL PERFORMANCE CURVES At TA = +25°C and VS = ±5V, unless otherwise noted. GAIN vs FREQUENCY COMMON-MODE REJECTION vs FREQUENCY 70 110 G = 1000 100 Common-Mode Rejection (dB) 60 Gain (dB) 50 G = 100 40 30 G = 20 20 G=5 10 0 90 80 70 G = 1000 60 50 G = 100 40 30 G=5 20 10 –10 0 100 1k 10k 100k 1M 1 10 100 1k 10k 100k Frequency (Hz) Frequency (Hz) POSITIVE POWER SUPPLY REJECTION vs FREQUENCY NEGATIVE POWER SUPPLY REJECTION vs FREQUENCY 100 100 80 Power Supply Rejection (dB) Power Supply Rejection (dB) G = 500 G = 100 60 40 G=5 20 0 G = 500 60 40 G = 100 G=5 20 0 10 100 1k 10k 100k 1M 1 10 100 1k 10k Frequency (Hz) Frequency (Hz) INPUT COMMON-MODE RANGE vs OUTPUT VOLTAGE, VS = ±15V, G = 5 INPUT COMMON-MODE VOLTAGE vs OUTPUT VOLTAGE, VS = ±5V, G = 5 100k 5 Input Common-Mode Voltage (V) 15 Common-Mode Voltage (V) 80 10 5 + VD/2 0 – + VD/2 VO Ref – + VCM –5 +15V –15V –10 Limited by A2 see text output swing— 4 3 VS = ±5V 2 VS = +5V/0V VREF = 2.5V 1 0 –1 VREF = 0V –2 –3 tput swing—see Limited by A2 ou –4 text –5 –15 –15 –10 –5 0 5 10 –5 15 ® INA122 –4 –3 –2 –1 0 1 Output Voltage (V) Output Voltage (V) 4 2 3 4 5 TYPICAL PERFORMANCE CURVES (CONT) At TA = +25°C and VS = ±5V, unless otherwise noted. VOLTAGE and CURRENT NOISE DENSITY vs FREQUENCY (RTI) SETTLING TIME vs GAIN 10 Settling Time (ms) Current Noise (fA/√Hz) 100 VN 10V Step 1 0.01% 0.1% IN 0.1 10 1 10 100 1k 1 10k 10 100 INPUT-REFERRED OFFSET VOLTAGE WARM-UP QUIESCENT CURRENT vs TEMPERATURE 10 80 6 Quiescent Current (µA) Turn-on time ≤ 1ms. Settling time to final value depends on Gain—see settling time. 8 Offset Voltage Change (µV) 1k Gain (V/V) Frequency (Hz) 4 2 (Noise) 0 –2 –4 –6 60 40 20 –8 –10 0 1 2 3 4 5 6 7 8 9 0 –75 10 –50 –25 0 25 50 75 Time After Turn-On (ms) Temperature (°C) TOTAL HARMONIC DISTORTION+NOISE vs FREQUENCY OUTPUT VOLTAGE SWING vs OUTPUT CURRENT 100 125 V+ 1 Output Voltage (V) (V+)–1 THD+N (%) Voltage Noise (nV/√Hz) 1000 G = 100 0.1 0.01 G=5 RL = ∞ Sourcing Current (V+)–2 (V–)+2 (V–)+1 Sinking Current RL = 25kΩ V– 0.001 10 100 1k 0 10k 5 10 15 20 25 Output Current (mA) Frequency (Hz) ® 5 INA122 TYPICAL PERFORMANCE CURVES (CONT) At TA = +25°C and VS = ±5V, unless otherwise noted. SMALL-SIGNAL STEP RESPONSE G=5 100mV/div 100mV/div SMALL-SIGNAL STEP RESPONSE G = 100 100µs/div LARGE-SIGNAL STEP RESPONSE G=5 INPUT-REFERRED NOISE VOLTAGE 0.1Hz to 10Hz 2V/div 2µV/div 50µs/div 500ms/div 50µs/div ® INA122 6 APPLICATION INFORMATION offset adjustment. Figure 2 shows an optional circuit for trimming the output offset voltage. The voltage applied to the Ref terminal is added to the output signal. An op amp buffer is used to provide low impedance at the Ref terminal to preserve good common-mode rejection. Figure 1 shows the basic connections required for operation of the INA122. Applications with noisy or high impedance power supplies may require decoupling capacitors close to the device pins. The output is referred to the output reference (Ref) terminal which is normally grounded. This must be a low-impedance connection to ensure good common-mode rejection. A resistance of 10Ω in series with the Ref pin will cause a typical device to degrade to approximately 80dB CMR. – VIN V+ RG IN SETTING THE GAIN Gain of the INA122 is set by connecting a single external resistor, RG, as shown: 200 kΩ RG 100µA 1/2 REF200 Ref V+ G=5+ VO INA122 10kΩ OPA336 ±10mV Adjustment Range (1) 100Ω 100Ω Commonly used gains and RG resistor values are shown in Figure 1. The 200kΩ term in equation 1 comes from the internal metal film resistors which are laser trimmed to accurate absolute values. The accuracy and temperature coefficient of these resistors are included in the gain accuracy and drift specifications of the INA122. 100µA 1/2 REF200 V– FIGURE 2. Optional Trimming of Output Offset Voltage. The stability and temperature drift of the external gain setting resistor, RG, also affects gain. RG’s contribution to gain accuracy and drift can be directly inferred from the gain equation (1). INPUT BIAS CURRENT RETURN PATH The input impedance of the INA122 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 –10nA (current flows out of the input terminals). High input impedance means that this input bias current changes very little with varying input voltage. OFFSET TRIMMING The INA122 is laser trimmed for low offset voltage and offset voltage drift. Most applications require no external V+ 0.1µF DESIRED GAIN (V/V) RG (Ω) NEAREST 1% RG VALUE 5 10 20 50 100 200 500 1000 2000 5000 10000 NC 40k 13.33k 4444 2105 1026 404 201 100.3 40 20 NC 40.2k 13.3k 4420 2100 1020 402 200 100 40.2 20 7 INA122 3 + VIN 8 6 A1 G = 5 + 200kΩ RG 100kΩ + – V–) G VO = (VIN IN 25kΩ + RG 25kΩ Load NC: No Connection. – 1 – VIN A2 2 100kΩ Also drawn in simplified form: V+ Ref 0.22µF 8 6 INA122 RG 1 5 4 3 IN – VIN VO 5 Single Supply VO Ref V– Dual Supply 2 FIGURE 1. Basic Connections. ® 7 INA122 INPUT PROTECTION The inputs of the INA122 are protected with internal diodes connected to the power supply rails (Figure 4). These diodes will clamp the applied signal to prevent it from damaging the input circuitry. If the input signal voltage can exceed the power supplies by more than 0.3V, the input signal current should be limited to less than 5mA to protect the internal clamp diodes. This can generally be done with a series input resistor. Some signal sources are inherently current-limited and do not require limiting resistors. 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 common-mode range of the INA122 and the input amplifiers will saturate. 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. Microphone, Hydrophone etc. INPUT COMMON-MODE RANGE The common-mode range for some common operating conditions is shown in the typical performance curves. The INA122 can operate over a wide range of power supply and VREF configurations, making it impractical to provide a comprehensive guide to common-mode range limits for all possible conditions. The most commonly overlooked overload condition occurs by attempting to exceed the output swing of A2, an internal circuit node that cannot be measured. Calculating the expected voltages at A2’s output (see equation in Figure 4) provides a check for the most common overload conditions. INA122 47kΩ 47kΩ Thermocouple INA122 The design of A1 and A2 are identical and their outputs can swing to within approximately 100mV of the power supply rails, depending on load conditions. When A2’s output is saturated, A1 can still be in linear operation, responding to changes in the non-inverting input voltage. This may give the appearance of linear operation but the output voltage is invalid. 10kΩ INA122 A single supply instrumentation amplifier has special design considerations. Using commonly available single-supply op amps to implement the two-op amp topology will not yield equivalent performance. For example, consider the condition where both inputs of common single-supply op amps are Center-tap provides bias current return. FIGURE 3. Providing an Input Common-Mode Current Path. V+ + + 0.5V VIN + VIN A1 (3) VO (8) V– 100kΩ 25kΩ RG V+ – – (V + – V – ) 25kΩ + 0.6V VO2 = 1.25VIN IN IN RG 25kΩ (1) (Voltages are referred to VREF) – + 0.5V VIN – VIN 100kΩ Ref (2) V– FIGURE 4. INA122 Simplified Circuit Diagram. ® INA122 (V–) + 0.1V ≤ V02 ≤ (V+) –0.1V V02 A2 8 equal to 0V. The outputs of both A1 and A2 must be 0V. But any small positive voltage applied to VIN+ requires that A2’s output must swing below 0V, which is clearly impossible without a negative power supply. Operation at very low supply voltage requires careful attention to ensure that the common-mode voltage remains within its linear range. To achieve common-mode range that extends to singlesupply ground, the INA122 uses precision level-shifting buffers on its inputs. This shifts both inputs by approximately +0.5V, and through the feedback network, shifts A2’s output by approximately +0.6V. With both inputs and VREF at single-supply, A2’s output is well within its linear range. A positive VIN+ causes A2’s output to swing below 0.6V. As a result of this input level-shifting, the voltages at pin 1 and pin 8 are not equal to their respective input terminal voltages (pins 2 and 3). For most applications, this is not important since only the gain-setting resistor connects to these pins. LOW QUIESCENT CURRENT OPERATION The INA122 maintains its low quiescent current (60µA) while the output is within linear operation (up to 200mV from the supply rails). When the input creates a condition that overdrives the output into saturation, quiescent current increases. With VO overdriven into the positive rail, the quiescent current increases to approximately 400µA. Likewise, with VO overdriven into the negative rail (single supply ground) the quiescent current increases to approximately 200µA. OUTPUT CURRENT RANGE Output sourcing and sinking current values versus the output voltage ranges are shown in the typical performance curves. The positive and negative current limits are not equal. Positive output current sourcing will drive moderate to high load impedances. Battery operation normally requires the careful management of power consumption to keep load impedances very high throughout the design. LOW VOLTAGE OPERATION The INA122 can be operated on a single power supply as low as +2.2V (or a total of +2.2V on dual supplies). Performance remains excellent throughout the power supply range up to +36V (or ±18V). Most parameters vary only slightly throughout this supply voltage range—see typical performance curves. +5V REF200 200µA + VIN 1kΩ VCM ≈ 100mV (60µA) ≈ 200mV 3 7 VO = 0.1V to 4.9V 8 RG INA122 1 – VIN 6 4 2 VO 5 Ref(1) NOTE: (1) To accomodate bipolar input signals, VREF can be offset to a positive voltage. Output voltage is then referred to the voltage applied to Ref. FIGURE 5. Micropower Single Supply Bridge Amplifier. V+ +5V Load 8 IL 1 2.5A + VIN Shunt RS 0.02Ω 3 7 8 50mV RG – VIN 6 INA122 1 2 VREF G = 100 D 1kΩ 2 +IN 5 0.47µF 4 6 Serial Data ADS7816 12-Bit A/D 3 CS –IN CLK 5 7 Chip Select Clock 4 Differential measurement avoids ground loop errors. FIGURE 6. Single-Supply Current Shunt Measurement. ® 9 INA122 PACKAGE OPTION ADDENDUM www.ti.com 14-Oct-2022 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Pins Package Drawing Qty Eco Plan (2) Lead finish/ Ball material MSL Peak Temp Op Temp (°C) Device Marking (3) Samples (4/5) (6) INA122P ACTIVE PDIP P 8 50 RoHS & Green Call TI N / A for Pkg Type INA122PA ACTIVE PDIP P 8 50 RoHS & Green Call TI INA122PAG4 ACTIVE PDIP P 8 50 RoHS & Green INA122U ACTIVE SOIC D 8 75 INA122U/2K5 ACTIVE SOIC D 8 INA122UA ACTIVE SOIC D INA122UA/2K5 ACTIVE SOIC D -40 to 85 INA122P Samples N / A for Pkg Type INA122P A Samples Call TI N / A for Pkg Type INA122P A Samples RoHS & Green Call TI Level-3-260C-168 HR INA 122U Samples 2500 RoHS & Green Call TI Level-3-260C-168 HR INA 122U Samples 8 75 RoHS & Green Call TI Level-3-260C-168 HR INA 122U A 8 2500 RoHS & Green Call TI Level-3-260C-168 HR INA 122U A (1) The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs. LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect. NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design. PREVIEW: Device has been announced but is not in production. Samples may or may not be available. OBSOLETE: TI has discontinued the production of the device. (2) RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may reference these types of products as "Pb-Free". RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption. Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of