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Texas Instruments INA111AU
- Part No.:
- INA111AU
- Manufacturer:
- Texas Instruments
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 16-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
INA111AU.pdf
- Description:
- IC INST AMP 1 CIRCUIT 16SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,197
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Product details
Overview
INA111AU from Texas Instruments (formerly Burr-Brown) is a high-speed, FET-input instrumentation amplifier optimized for precision signal conditioning in noisy, high-impedance sensor interfaces. It delivers 4µs settling time to 0.01% at G = 100, 106dB minimum CMRR at G = 100, and input bias current ≤20pA - enabling accurate amplification of thermocouple, bridge transducer, and medical bio-potential signals.
For engineers reviewing the INA111AU datasheet, INA111AU pinout, INA111AU application, or INA111AU equivalent, key selection considerations include its current-feedback topology (2MHz bandwidth at G = 1), laser-trimmed DC accuracy (±500µV max offset), SOL-16 surface-mount package with output sense pin (Pin 12), and –40°C to +85°C industrial temperature rating.
Technical Context
The INA111AU employs a three-op-amp current-feedback architecture with internal 25kΩ/10kΩ resistor networks, enabling wide bandwidth (2MHz at G = 1) and fast settling (4µs @ G = 100). Gain is set by a single external resistor RG per the equation G = 1 + 50kΩ/RG, supporting 1–10,000× gain range.
Its FET-input stage achieves ≤20pA input bias current and 10¹²Ω || 3pF common-mode input impedance, minimizing loading on high-Z sources. The SOL-16 package includes dedicated output sense (Pin 12) for remote load feedback, unlike the DIP version where this path is internal.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Gain Bandwidth | 2MHz at G = 1; enables wideband sensor signal acquisition without phase distortion |
| Settling Time | 4µs to 0.01% at G = 100; supports high-speed data acquisition with minimal transient error |
| Input Bias Current | ≤20pA max; reduces voltage error across high-impedance source resistors (e.g., >1MΩ) |
| CMRR | 106dB min at G = 100, 10Hz–10kHz; rejects EMI-coupled noise in industrial environments |
| Offset Voltage | ±500µV max at +25°C; ensures <0.5mV absolute error in 1V full-scale medical or strain-gauge systems |
| Supply Range | ±6V to ±18V; compatible with standard dual-rail lab and industrial power supplies |
| Operating Temp | –40°C to +85°C; qualified for embedded industrial control and test equipment deployment |
Pinout & Package
SOL-16 surface-mount package (TI package code DW), 16-pin SOIC with gull-wing leads, moisture sensitivity level 3 (260°C reflow), body size 10.3mm × 7.5mm × 2.35mm.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 3, 5, 7, 9, 13, 15 | No Connect (NC) | Internally unused; must remain unconnected to avoid parasitic coupling |
| 2 | RG | External gain-setting resistor connection; determines G = 1 + 50kΩ/RG |
| 4 | V– | Negative supply rail; decoupling capacitor required within 1cm for stability |
| 6, 10 | VIN– / VIN+ | Differential input terminals; require matched trace routing to preserve CMRR |
| 8 | V+ | Positive supply rail; decoupling capacitor required within 1cm for stability |
| 11 | VO | Main output; drives load directly but benefits from remote sensing via Pin 12 |
| 12 | Feedback | Output sense node; must connect to VO (Pin 11) or remote load for closed-loop accuracy |
| 14 | Ref | Output reference terminal; low-impedance ground connection essential for CMRR integrity |
| 16 | NC | No Connect; electrically isolated; leave floating |
Key Features
| Feature | Design Value |
|---|---|
| Current-feedback topology | Delivers flat 2MHz bandwidth from G = 1 to G = 10, eliminating gain-bandwidth trade-off in sensor front-ends |
| Laser-trimmed thin-film resistors | Ensures ±0.15% gain error at G = 100 and ±5µV/°C offset drift for stable calibration over temperature |
| FET input stage | Enables direct interface to piezoelectric sensors, pH electrodes, and thermocouples without bias-current compensation networks |
| Output sense pin (Pin 12) | Allows Kelvin sensing at remote loads to eliminate errors from PCB trace resistance and contact voltage drops |
| High-frequency CMRR preservation | Maintains >80dB CMRR up to 100kHz via balanced input layout guidance and internal topology |
Applications
| Medical Instrumentation | Data Acquisition |
|---|---|
|
Use Scenario: Amplifying microvolt-level ECG/EEG signals from dry electrodes in portable patient monitors. IC Role / Device Role / Timing Role: Primary signal-conditioning stage providing differential gain, common-mode rejection, and DC-coupled baseline stability. Use Value: 20pA input bias avoids electrode polarization artifacts; 4µs settling supports 250ksps sampling with <0.01% step response error. |
Use Scenario: Conditioning outputs from 350Ω strain-gauge bridges in structural health monitoring nodes. IC Role / Device Role / Timing Role: Precision instrumentation amplifier with programmable gain for ratiometric bridge excitation and measurement. Use Value: Laser-trimmed offset (<500µV) and 106dB CMRR reject power-line interference in unshielded industrial wiring. |
| Bridge Transducer Systems | Industrial Process Control |
|
Use Scenario: Signal conditioning for load cells and pressure sensors in factory automation weighing systems. IC Role / Device Role / Timing Role: High-Z input amplifier driving SAR ADC inputs with minimal gain error and thermal drift. Use Value: ±5µV/°C offset drift ensures <0.02%FS error over –25°C to +70°C ambient without recalibration. |
Use Scenario: Isolated analog input module for PLC analog I/O cards measuring 4–20mA loop signals. IC Role / Device Role / Timing Role: Input-stage amplifier before isolation barrier, rejecting common-mode noise from motor drives and VFDs. Use Value: 10¹²Ω input impedance prevents loading of precision shunt resistors; 2MHz bandwidth supports anti-alias filtering at 100kHz. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar instrumentation amplifier applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AD620ARZ | Voltage-feedback topology; 120dB CMRR at DC, but bandwidth collapses to 1MHz at G = 100; higher 1.0nV/√Hz noise at 1kHz | Better DC precision for static measurements; inferior settling (15µs @ 0.01%) limits high-speed DAQ use | Select AD620ARZ when ultra-low offset (50µV max) and drift (0.6µV/°C) outweigh speed requirements |
| INA128UA | Lower bandwidth (1.3MHz @ G = 1); 400µV max offset; no output sense pin; SO-8 package only | Cost-optimized for general-purpose industrial sensors where 16-pin footprint and remote sensing are unnecessary | Choose INA128UA for space-constrained designs needing basic instrumentation performance without SOL-16 features |
Compared with AD620ARZ and INA128UA, the INA111AU uniquely combines current-feedback speed (4µs settling), FET-input low bias current, and SOL-16 output sense capability - making it optimal for high-accuracy, high-speed sensor front-ends requiring remote load regulation and minimal thermal drift.
Availability
INA111AU is available at Aetrix Electronics and suitable for medical instrumentation, industrial data acquisition, bridge transducer systems, and process control applications requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for INA111AU includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Texas Instruments (TI) is a global semiconductor leader specializing in analog and embedded processing technologies, with deep heritage in precision amplifiers dating to Burr-Brown's 1992 acquisition.
The INA111AU belongs to TI's legacy instrumentation amplifier product line, designed specifically for high-fidelity signal extraction from low-level, high-impedance sensors in demanding industrial and medical environments.
FAQ
What is the function of Pin 12 (Feedback) on the INA111AU?
Pin 12 is the output sense terminal, unique to the SOL-16 package. It must be connected-typically to Pin 11 (VO) or directly to the load-to close the feedback loop externally. This enables Kelvin sensing, eliminating errors from PCB trace resistance and contact voltage drops. Unlike the DIP version, the INA111AU requires this explicit connection for specified accuracy and stability.
Can the INA111AU operate with a single supply?
No, the INA111AU is specified only for dual-supply operation (±6V to ±18V). Its input common-mode range extends to ±12V and output swing to ±12.7V, requiring symmetric rails. Single-supply use violates absolute maximum ratings and causes input stage saturation; TI does not characterize or guarantee performance under single-rail conditions for the INA111AU.
What is the minimum recommended RG value for stable operation of the INA111AU?
The minimum recommended RG is 4.99Ω (for G ≈ 10,000), per TI's application table. However, for gains ≥100, RG ≤ 511Ω requires careful PCB layout: short, matched traces and avoidance of sockets, as wiring resistance introduces unstable gain error. TI specifies 0.25% gain error max at G = 1000 with RG = 50Ω, confirming viability down to ~10Ω with proper implementation.
How does the INA111AU's current-feedback architecture affect frequency response?
The current-feedback design yields a +6dB/octave gain rise near 2MHz in unity gain-a predictable zero, not instability. To flatten response, TI recommends adding a simple pole ≤700kHz (e.g., RC filter at input). This architecture maintains 2MHz bandwidth from G = 1 to G = 10, unlike voltage-feedback amps where bandwidth scales inversely with gain-making the INA111AU ideal for variable-gain sensor interfaces.
Is the INA111AU RoHS compliant and lead-free?
Yes, the INA111AU is RoHS compliant with lead-free (NIPDAU) termination, per TI's packaging addendum. It carries MSL Level-3 rating (260°C peak reflow, 168-hour floor life) and is qualified for lead-free soldering processes. The part marking "INA111AU" appears on the top surface, and full compliance documentation is available in TI's official materials database.
INA111AU Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 16-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Amplifier Type:
- Instrumentation
- Number of Circuits:
- 1
- Output Type:
- -
- Slew Rate:
- 17V/µs
- Gain Bandwidth Product:
- -
- -3db Bandwidth:
- 2 MHz
- Current - Input Bias:
- 2 pA
- Voltage - Input Offset:
- 200 µV
- Current - Supply:
- 3.3mA
- Current - Output / Channel:
- 30 mA
- Voltage - Supply Span (Min):
- 12 V
- Voltage - Supply Span (Max):
- 36 V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-SOIC
INA111AU FAQ
1.How can I place an order for INA111AU through Aetrix?
Please submit a Request for Quotation (RFQ) for INA111AU on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for INA111AU reliable?
The price and inventory of INA111AU are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for INA111AU is usually 5 days.
3.What payment methods are accepted for INA111AU?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for INA111AU transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for INA111AU?
INA111AU orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your INA111AU order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for INA111AU?
For technical support, including INA111AU datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your INA111AU requirements.
6.How does Aetrix verify that INA111AU is sourced from the original manufacturer or authorized distributors?
All INA111AU products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that INA111AU meets industry standards.
7.What is the process for return or replacement of INA111AU?
All INA111AU units undergo pre-shipment inspection (PSI). If there is an issue with INA111AU, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The INA111AU part is unused and in its original packaging.
Return procedure for INA111AU:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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