INA126. MicroPOWER INSTRUMENTATION AMPLIFIER Single and Dual Versions IN ) G V IN G = 5 +

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1 INA6 INA6 INA6 INA6 INA6 INA6 INA6 SBOS06A JANUARY 996 REVISED AUGUST 005 MicroPOWER INSTRUMENTATION AMPLIFIER Single and Dual Versions FEATURES LOW QUIESCENT CURRENT: 75µA/chan. WIDE SUPPLY RANGE: ±.35V to ±8V LOW OFFSET VOLTAGE: 50µV max LOW OFFSET DRIFT: 3µV/ C max LOW NOISE: 35nV/ Hz LOW INPUT BIAS CURRENT: 5nA max 8-PIN DIP, SO-8, MSOP-8 SURFACE- MOUNT DUAL: 6-Pin DIP, SO-6, SSOP-6 APPLICATIONS INDUSTRIAL SENSOR AMPLIFIER: Bridge, RTD, Thermocouple PHYSIOLOGICAL AMPLIFIER: ECG, EEG, EMG MULTI-CHANNEL DATA ACQUISITION PORTABLE, BATTERY OPERATED SYSTEMS 3 8 V 7 0kΩ 0kΩ INA6 6 5 V O = (V IN V IN ) G 80kΩ G = 5 DESCRIPTION The INA6 and INA6 are precision instrumentation amplifiers for accurate, low noise differential signal acquisition. Their two-op-amp design provides excellent performance with very low quiescent current (75µA/channel). This, combined with a wide operating voltage range of ±.35V to ±8V, makes them ideal for portable instrumentation and data acquisition systems. Gain can be set from 5V/V to 0000V/V with a single external resistor. Laser trimmed input circuitry provides low offset voltage (50µV max), low offset voltage drift (3µV/ C max) and excellent common-mode rejection. Single version package options include 8-pin plastic DIP, SO-8 surface mount, and fine-pitch MSOP-8 surface-mount. Dual version is available in the space-saving SSOP-6 finepitch surface mount, SO-6, and 6-pin DIP. All are specified for the 0 C to 85 C industrial temperature range. V INA6 0kΩ 0kΩ 0kΩ V O = ( V IN ) G G = 5 V O = (V IN V IN ) G G = 5 80kΩ 80kΩ V 6 8 0kΩ V Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet. All trademarks are the property of their respective owners. PRODUCTION DATA information is current as of publication date. Products conform to specifications per the terms of Texas Instruments standard warranty. Production processing does not necessarily include testing of all parameters. Copyright , Texas Instruments Incorporated

2 ABSOLUTE MAXIMUM RATINGS () Power Supply Voltage, V to V... 36V Input Signal Voltage ()... (V)0.7 to (V)0.7V Input Signal Current ()... 0mA Output Short Circuit... Continuous Operating Temperature C to 5 C Storage Temperature C to 5 C Lead Temperature (soldering, 0s) C NOTES: () Stresses above these ratings may cause permanent damage. () Input signal voltage is limited by internal diodes connected to power supplies. See text. PIN CONFIGURATION (Single) ELECTROSTATIC DISCHARGE SENSITIVITY This integrated circuit can be damaged by ESD. Texas Instruments 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. Top View 8-Pin DIP, SO-8, MSOP-8 PACKAGE/ORDERING INFORMATION 8 PACKAGE PRODUCT PACKAGE-LEAD MARKING V IN 7 V Single V IN V V O Ref INA6PA DIP-8 INA6PA INA6P DIP-8 INA6P INA6UA SO-8 INA6UA INA6U SO-8 INA6U INA6EA () MSOP-8 A6 (3) PIN CONFIGURATION (Dual) Top View 6-Pin DIP, SO-6, SSOP-6 " " " INA6E () MSOP-8 A6 (3) " " " Dual A 6 B INA6PA DIP-6 INA6PA INA6P DIP-6 INA6P A 5 B INA6UA SO-6 INA6UA INA6U SO-6 INA6U A A Ref A B B Ref B INA6EA () SSOP-6 INA6EA " " " INA6E () SSOP-6 INA6E " " " V OA Sense A V V OB Sense B V NOTES: () For the most current package and ordering information, see the Package Option Addendum at the end of this document, or see the TI website at. () MSOP-8 and SSOP-6 packages are available only on 50 or 500 piece reels. (3) Grade designation is marked on reel. INA6, INA6 SBOS06A

3 ELECTRICAL CHARACTERISTICS At T A = 5 C, V S = ±5V, R L = 5kΩ, unless otherwise noted. INA6P, U, E INA6P, U, E INA6PA, UA, EA INA6PA, UA, EA PARAMETER CONDITIONS MIN TYP MAX MIN TYP MAX UNITS INPUT Offset Voltage, RTI ±00 ±50 ±50 ±500 µv vs Temperature ±0.5 ±3 ±5 µv/ C vs Power Supply (PSRR) V S = ±.35V to ±8V µv/v Input Impedance 0 9 Ω pf Safe Input Voltage R S = 0 (V)0.5 (V)0.5 V R S = kω (V)0 (V)0 V Common-Mode Voltage Range V O = 0V ±.5 ±.5 V Channel Separation (dual) G = 5, dc 30 db Common-Mode Rejection R S = 0, V CM = ±.5V db INA6U (dual SO-6) 80 9 db INPUT BIAS CURRENT na vs Temperature ±30 pa/ C Offset Current ±0.5 ± ±5 na vs Temperature ±0 pa/ C GAIN G = 5 to 0k V/V Gain Equation G = 5 80kΩ/ V/V Gain Error V O = ±V, G = 5 ±0.0 ±0. ±0.8 % vs Temperature G = 5 ± ±0 ppm/ C Gain Error V O = ±V, G = 00 ±0. ±0.5 ± % vs Temperature G = 00 ±5 ±00 ppm/ C Nonlinearity G = 00, V O = ±V ±0.00 ±0.0 % NOISE Voltage Noise, f = khz 35 nv/ Hz f = 00Hz 35 nv/ Hz f = 0Hz 5 nv/ Hz f B = 0.Hz to 0Hz 0.7 µv PP Current Noise, f = khz 60 fa/ Hz f B = 0.Hz to 0Hz pa PP OUTPUT Voltage, Positive R L = 5kΩ (V)0.9 (V)0.75 V Negative R L = 5kΩ (V)0.95 (V)0.8 V Short-Circuit Current Short-Circuit to Ground 0/5 ma Capacitive Load Drive 000 pf FREQUENCY RESPONSE Bandwidth, 3dB G = 5 00 khz G = 00 9 khz G = khz Slew Rate V O = ±0V, G = 5 0. V/µs Settling Time, 0.0% 0V Step, G = 5 30 µs 0V Step, G = µs 0V Step, G = µs Overload Recovery 50% Input Overload µs POWER SUPPLY Voltage Range ±.35 ±5 ±8 V Current (per channel) I O = 0 ±75 ±00 µa TEMPERATURE RANGE Specification Range 0 85 C Operation Range 55 5 C Storage Range 55 5 C Thermal Resistance, θ JA 8-Pin DIP 00 C/W SO-8 Surface-Mount 50 C/W MSOP-8 Surface-Mount 00 C/W 6-Pin DIP (dual) 80 C/W SO-6 (dual) 00 C/W SSOP-6 (dual) 00 C/W Specification same as INA6P, INA6U, INA6E; INA6P, INA6U, INA6E. INA6, INA6 3 SBOS06A

4 TYPICAL CHARACTERISTICS At T A = 5 C and V S = ±5V, unless otherwise noted. Gain (db) GAIN vs FREQUENCY G = G = G = 0 G = k 0k 00k M Common-Mode Rejection (db) COMMON-MODE REJECTION vs FREQUENCY G = G = G = k 0k 00k M Frequency (Hz) Frequency (Hz) 0 POSITIVE POWER SUPPLY REJECTION vs FREQUENCY G = NEGATIVE POWER SUPPLY REJECTION vs FREQUENCY Power Supply Rejection (db) G = 5 G = 00 Power Supply Rejection (db) G = 000 G = 5 G = k 0k 00k M Frequency (Hz) k 0k 00k M Frequency (Hz) Common-Mode Voltage (V) INPUT COMMON-MODE RANGE vs OUTPUT VOLTAGE, V S = ±5V Limited by A output swing see text 5V V D/ V D/ Ref V CM 5V V O Limited by A output swing see text Input Common-Mode Voltage (V) INPUT COMMON-MODE VOLTAGE RANGE vs OUTPUT VOLTAGE, V S = ±5V Limited by A output swing see text V S = ±5V V S = 5V/0V V REF =.5V Limited by A output swing see text Output Voltage (V) Output Voltage (V) INA6, INA6 SBOS06A

5 TYPICAL CHARACTERISTICS (Cont.) At T A = 5 C and V S = ±5V, unless otherwise noted. 00 INPUT-REFERRED NOISE vs FREQUENCY k 000 SETTLING TIME vs GAIN Input Voltage Noise (nv/ Hz) 0 Voltage Noise Current Noise 00 Input Current Noise (fa/ Hz) Settling Time (µs) % 0.% 0 00 k 0k Frequency (Hz) k Gain (V/V) Offset Voltage Change (µv) INPUT-REFERRED OFFSET VOLTAGE WARM-UP Time After Turn-On (ms) (Noise) Quiescent Current (µa) QUIESCENT CURRENT AND SLEW RATE vs TEMPERATURE I Q Temperature ( C) SR SR V S = ±.35V V S = ±5V Slew Rate (V/µs) TOTAL HARMONIC DISTORTIONNOISE vs FREQUENCY V OUTPUT VOLTAGE SWING vs OUTPUT CURRENT (V) Sourcing Current THDN (%) R L = Output Voltage (V) (V) (V) G = 5 R L = 00kΩ (V) Sinking Current k Frequency (Hz) 0k V Output Current (ma) INA6, INA6 5 SBOS06A

6 TYPICAL CHARACTERISTICS (Cont.) At T A = 5 C and V S = ±5V, unless otherwise noted. SMALL-SIGNAL RESPONSE, G = 5 SMALL-SIGNAL RESPONSE, G = 00 0mV/div 0mV/div 50µs/div 50µs/div LARGE-SIGNAL RESPONSE, G = 5 VOLTAGE NOISE, 0.Hz to 0Hz 5V/div 0.µV/div 50µs/div 500ms/div CHANNEL SEPARATION vs FREQUENCY, RTI (Dual Version) G = 000 Separation (db) R L = 5kΩ Measurement limited by amplifier or measurement noise. G = 00 G = k 0k 00k M Frequency (Hz) 6 INA6, INA6 SBOS06A

7 APPLICATION INFORMATION Figure shows the basic connections required for operation of the INA6. Applications with noisy or high impedance power supplies may require decoupling capacitors close to the device pins as shown. 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 8Ω in series with the Ref pin will cause a typical device to degrade to approximately 80dB CMR. Dual versions (INA6) have feedback sense connections, Sense A and Sense B. These must be connected to their respective output terminals for proper operation. The sense connection can be used to sense the output voltage directly at the load for best accuracy. SETTING THE GAIN Gain is set by connecting an external resistor,, as shown: G =5 80kΩ Commonly used gains and resistor values are shown in Figure. The 80kΩ term in equation 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. The stability and temperature drift of the external gain setting resistor,, also affects gain. s contribution to gain accuracy and drift can be directly inferred from the gain () equation (). Low resistor values required for high gain can make wiring resistance important. Sockets add to the wiring resistance, which will contribute additional gain error in gains of approximately 00 or greater. OFFSET TRIMMING The INA6 and INA6 are laser trimmed for low offset voltage and offset voltage drift. Most applications require no external offset adjustment. Figure 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. INA6 Ref OPA37 ±0mV Adjustment Range Dual version has external sense connection. 00µA / REF00 00Ω 00Ω 00µA / REF00 FIGURE. Optional Trimming of Output Offset Voltage. V O V V V DESIRED GAIN NEAREST % (V/V) (Ω) VALUE 5 NC NC 0 6k 5.8k Pin numbers are for single version 3 8 INA6 A 7 0.µF 0kΩ 6 Load G = 5 80kΩ V O = (V IN V IN ) G V O NC: No Connection. Also drawn in simplified form: A V IN 0kΩ 0.µF 5 Ref INA6 Ref V O Dual version has external sense connection. V FIGURE. Basic Connections. INA6, INA6 7 SBOS06A

8 INPUT BIAS CURRENT RETURN The input impedance of the INA6/6 is extremely high approximately 0 9 Ω. However, a path must be provided for the input bias current of both inputs. This input bias current is typically 0nA (current flows out of the input terminals). High input impedance means that this input bias current changes very little with varying input voltage. 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 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 advantages of lower input offset voltage due to bias current and better high-frequency common-mode rejection. Microphone, Hydrophone etc. Thermocouple 7kΩ FIGURE 3. Providing an Input Common-Mode Current Path. INPUT COMMON-MODE RANGE The input common-mode range of the INA6/6 is shown in the typical characteristic curves. The commonmode range is limited on the negative side by the output voltage swing of A, an internal circuit node that cannot be measured on an external pin. The output voltage of A can be expressed as: 7kΩ INA6 V O =.5 ( ) (/ ) () (Voltages referred to Ref terminal, pin 5) INA6 INA6 Center-tap provides bias current return. The internal op amp A is identical to A and its output swing is limited to typically 0.7V from the supply rails. When the input common-mode range is exceeded (A s output is saturated), A can still be in linear operation and respond to changes in the non-inverting input voltage. The output voltage, however, will be invalid. LOW VOLTAGE OPERATION The INA6/6 can be operated on power supplies as low as ±.35V. Performance remains excellent with power supplies ranging from ±.35V to ±8V. Most parameters vary only slightly throughout this supply voltage range see typical characteristic curves. Operation at very low supply voltage requires careful attention to ensure that the commonmode voltage remains within its linear range. See Input Common-Mode Voltage Range. The INA6/6 can be operated from a single power supply with careful attention to input common-mode range, output voltage swing of both op amps and the voltage applied to the Ref terminal. Figure shows a bridge amplifier circuit operated from a single 5V power supply. The bridge provides an input common-mode voltage near.5v, with a relatively small differential voltage. INPUT PROTECTION The inputs are protected with internal diodes connected to the power supply rails. These diodes will clamp the applied signal to prevent it from exceeding the power supplies by more than approximately 0.7V. If the signal source voltage can exceed the power supplies, the source current should be limited to less than 0mA. This can generally be done with a series resistor. Some signal sources are inherently currentlimited and do not require limiting resistors. CHANNEL CROSSTALK DUAL VERSION The two channels of the INA6 are completely independent, including all bias circuitry. At DC and low frequency 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 crosstalk 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. Carefully balance the stray capacitance of each input to ground, and 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 that is rejected by the IA s input. 8 INA6, INA6 SBOS06A

9 5V The ADS787 s V REF input current is proportional to conversion rate. A conversion rate of 0kS/s or slower assures enough current to turn on the reference diode. Converter input range is ±.V. Output swing limitation of INA6 limits the A/D converter to somewhat greater than bits of range. Bridge Sensor.5V V.5V V INA6 A 0kΩ A 0kΩ 6 5.V R kω C 0.7µF R kω R, C, R : 30Hz LP 33µA 3 IN IN V REF 8 ADS787 -Bit A/D INA6 and ADS787 are available in fine-pitch MSOP-8 package D C S Ck 6 Serial Data 5 7 Chip Select Clock 6 8 REF00C-. A similar instrumentation amplifier, INA5, provides an internal reference voltage for sensor excitation and/or A/D converter reference. Dual version has external sense connection. Pin numbers shown are for single version. FIGURE. Bridge Signal Acquisition Single 5V Supply. R INA6 Ref I B V I O = IN G R A I O A I B Error Load OPA77 OPA30 OPA60 OPA9 ±.5nA ±0pA ±pa ±00fA Dual version has external sense connection. FIGURE 5. Differential Voltage-to-Current Converter. INA6, INA6 9 SBOS06A

10 PACKAGE MATERIALS INFORMATION 8-Apr-03 TAPE AND REEL INFORMATION *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Reel Diameter (mm) Reel Width W (mm) A0 (mm) B0 (mm) K0 (mm) P (mm) W (mm) Pin Quadrant INA6E/50 VSSOP DGK Q INA6EA/50 VSSOP DGK Q INA6UA/K5 SOIC D Q Pack Materials-Page

11 PACKAGE MATERIALS INFORMATION 8-Apr-03 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) INA6E/50 VSSOP DGK INA6EA/50 VSSOP DGK INA6UA/K5 SOIC D Pack Materials-Page

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