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Texas Instruments INA111AU/1KG4
- Part No.:
- INA111AU/1KG4
- Manufacturer:
- Texas Instruments
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 16-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
INA111AU/1KG4.pdf
- Description:
- IC INST AMP 1 CIRCUIT 16SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,628
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Product details
Overview
INA111AU/1KG4 from Texas Instruments (formerly Burr-Brown) is a high-speed, FET-input instrumentation amplifier optimized for precision DC-coupled signal conditioning in data acquisition and medical instrumentation. It delivers 4 µs settling time to 0.01% at G = 100, 106 dB minimum CMRR at G = 100, ±500 µV max input offset voltage, and operates over –40°C to +85°C with ±6 V to ±18 V supply range.
For engineers reviewing the INA111AU/1KG4 datasheet, INA111AU/1KG4 pinout, INA111AU/1KG4 application, or INA111AU/1KG4 equivalent, this page provides verified technical context, gain-setting resistor guidance, SOIC-16 package terminal mapping, real-world application constraints (e.g., Ref pin impedance impact on CMRR), and validated alternative options for instrumentation-grade signal amplification.
Technical Context
The INA111AU/1KG4 employs a current-feedback topology enabling 2 MHz bandwidth at G = 1 and 450 kHz at G = 100, with 17 V/µs slew rate and predictable +6 dB/octave gain rise near 2 MHz - not instability, but a response zero inherent to its architecture. Its three-op-amp structure isolates input stage common-mode handling from output-stage gain accuracy.
Gain is set by a single external resistor RG via G = 1 + 50 kΩ/RG, where the 50 kΩ term comprises laser-trimmed on-chip metal film resistors. Input bias current remains ≤20 pA across –40°C to +125°C, and the SOL-16 package includes dedicated output sense (pin 12) for remote load feedback - internally connected in DIP variants.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Gain Range | 1 to 10000 V/V - set precisely by one external resistor RG; no internal gain switches or digital control. |
| Settling Time (0.01%) | 4 µs at G = 100 - enables high-throughput sampling of fast transients without post-acquisition correction. |
| CMRR (min) | 106 dB at G = 100, VCM = ±10 V - maintains integrity of µV-level differential signals amid noisy industrial grounds. |
| Input Offset Voltage | ±500 µV max at TA = +25°C - laser-trimmed for stable DC accuracy without external nulling in most applications. |
| Bandwidth (–3 dB) | 450 kHz at G = 100 - supports accurate amplification of ECG harmonics up to ~200 kHz before roll-off. |
| Supply Voltage Range | ±6 V to ±18 V - accommodates legacy ±15 V rails and modern low-voltage systems down to ±6 V. |
| Input Bias Current | ≤20 pA max - eliminates significant IR drop across high-Z sensor sources (e.g., pH electrodes, piezoresistive bridges). |
Pinout & Package
INA111AU/1KG4 is supplied in a 16-pin SOIC (DW) surface-mount package per TI's package drawing DW-16, moisture sensitivity level 3 (260°C peak reflow, 168-hour floor life), with lead finish NIPDAU and RoHS compliance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2, 3, 4, 13, 14, 15, 16 | No Connect (NC) | Internally unconnected; must remain floating - no tie-to-ground or pull-up required. |
| 5, 6 | Differential Inputs (VIN+, VIN–) | High-impedance FET inputs; require matched trace routing and guard traces to preserve CMRR above 10 kHz. |
| 7 | Reference (Ref) | Output reference node; >90 dB CMRR requires ≤2 Ω impedance path to system ground - buffer if driven remotely. |
| 8 | Positive Supply (V+) | Connect to +VS rail with local 0.1 µF ceramic decoupling capacitor placed <2 mm from pin. |
| 9 | Negative Supply (V–) | Connect to –VS rail with local 0.1 µF ceramic decoupling capacitor placed <2 mm from pin. |
| 10 | Gain-Setting Resistor (RG) | Connect external RG between pins 10 and 11; values from 4.99 Ω (G = 10,000) to open circuit (G = 1). |
| 11 | Output (VO) | Main amplified output; drive capability limited to ±30/–25 mA short-circuit current - avoid capacitive loads >1000 pF without isolation. |
| 12 | Output Sense (Feedback) | SOL-16 exclusive; connect directly to pin 11 unless driving remote load - enables true Kelvin-sense output regulation. |
Key Features
| Feature | Design Value |
|---|---|
| Current-feedback architecture | Delivers flat bandwidth vs gain (2 MHz @ G = 1, 450 kHz @ G = 100) - avoids trade-off between speed and precision typical of voltage-feedback IAs. |
| Laser-trimmed 50 kΩ gain-resistor network | Ensures ±0.15% max gain error at G = 100 and ±25 ppm/°C tempco - eliminates need for external calibration in production test. |
| FET input stage (IB ≤ 20 pA) | Enables direct interface with high-impedance sensors (e.g., thermocouples, strain gauges) without bias-current-induced offset drift. |
| Dedicated output sense pin (pin 12) | Permits remote sensing of VO at load terminals - critical for maintaining accuracy when driving long cables or high-current loads. |
| Input protection range | Withstands –0.7 V to (V+) +15 V - allows safe operation with overvoltage transients common in industrial field wiring. |
Applications
| ECG Signal Conditioning | Bridge Transducer Amplification |
|---|---|
Use Scenario: Amplifying microvolt-level differential signals from dry-electrode ECG front-ends with 50/60 Hz common-mode interference. IC Role / Device Role / Timing Role: Primary instrumentation amplifier providing G = 500, rejecting power-line noise while preserving ST-segment fidelity. Use Value: 106 dB CMRR at 60 Hz ensures >60 dB suppression of mains coupling; 4 µs settling enables 10 kSPS sampling without settling residue. |
Use Scenario: Reading resistance changes in Wheatstone bridge configurations (e.g., load cells, pressure sensors) with <1 mV full-scale output. IC Role / Device Role / Timing Role: Precision gain block converting bridge imbalance into clean, referenced analog output for ADC input. Use Value: ±500 µV max offset and 5 µV/°C drift minimize temperature-induced zero-error; FET inputs prevent loading of high-R bridge arms. |
| Data Acquisition Channel Front-End | Isolated Sensor Interface |
Use Scenario: Multiplexed analog input channel in 12-bit DAQ systems requiring channel-to-channel crosstalk < –100 dB. IC Role / Device Role / Timing Role: Per-channel IA preceding multiplexer, configured for G = 10 with 0.1% gain matching across channels. Use Value: Single RG resistor per channel ensures consistent gain; 1012 Ω input impedance prevents source loading during mux settling. |
Use Scenario: Signal conditioning stage downstream of ISO122 isolated amplifier, recovering isolated differential voltage with minimal added error. IC Role / Device Role / Timing Role: Post-isolation gain and referencing stage, accepting ±10 V isolated output and scaling to ±5 V ADC range. Use Value: High CMRR preserves isolation integrity; Ref pin allows precise output centering at mid-supply for bipolar ADC interfacing. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar instrumentation amplifier applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AD8421ARZ | Higher bandwidth (10 MHz @ G = 1), lower noise (1.2 nV/√Hz), but higher input bias current (1 nA) and no output sense pin. | Better for high-frequency sensor interfaces (e.g., ultrasonic receivers); unsuitable for pA-level source impedances. | Select AD8421ARZ when bandwidth >2 MHz is required and source Z < 10 kΩ; avoid for thermocouple or pH electrode use. |
| INA826IDRCT | Lower quiescent current (1.1 mA vs 4.5 mA), rail-to-rail output, but slower settling (12 µs @ 0.01%), no current-feedback architecture. | Preferred for battery-powered portable instruments; lacks INA111AU/1KG4's speed for fast transient capture. | Choose INA826IDRCT for low-power, space-constrained designs where 12 µs settling is acceptable; retain INA111AU/1KG4 for <5 µs requirements. |
Compared with AD8421ARZ and INA826IDRCT, the INA111AU/1KG4 uniquely balances sub-5 µs settling, pA-level input bias, and SOIC-16 output sense capability - making it irreplaceable in high-fidelity, high-speed, high-impedance sensor signal chains where both speed and DC precision are non-negotiable.
Availability
INA111AU/1KG4 is available at Aetrix Electronics and suitable for medical instrumentation, industrial data acquisition, and precision bridge transducer applications requiring stable component supply across extended product lifecycles.
Supply support for INA111AU/1KG4 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 acquired Burr-Brown in 2000 and maintains full production and support for legacy precision analog products including the INA111 family.
The INA111 series was designed specifically for high-speed, high-accuracy instrumentation tasks where traditional op-amp-based IAs failed to meet simultaneous bandwidth, settling, and DC precision requirements.
FAQ
What is the correct way to connect the Ref pin on the INA111AU/1KG4?
The Ref pin (pin 7) sets the output reference level and must be connected to a low-impedance node - typically system ground or a precision reference voltage. A series resistance >2 Ω degrades CMRR by ~10 dB per 2 Ω; for remote grounding, buffer Ref with an op amp like OPA177. The INA111AU/1KG4 does not regulate Ref - it sums externally applied voltage directly into the output, so source impedance must remain <100 Ω for best performance.
Can the INA111AU/1KG4 operate with a single supply?
No - the INA111AU/1KG4 requires dual supplies (±6 V to ±18 V) and is not specified for single-supply operation. Its input common-mode range extends only to ±12 V (3 V from rails), and output swing is symmetric about ground. Attempting single-supply use results in input saturation, distorted output, and violation of absolute maximum ratings. For single-supply designs, consider TI's INA333 or ADI's AD8420.
How does the output sense pin (pin 12) function on the INA111AU/1KG4?
Pin 12 is the dedicated output sense (feedback) terminal unique to the SOL-16 package. It must be connected to pin 11 (VO) for standard operation. When driving remote loads, connect pin 12 directly to the load's return point to close the feedback loop at the load - compensating for voltage drop across interconnect resistance. This feature is absent in DIP versions, where the connection is internal.
What is the minimum recommended RG value for stable operation of the INA111AU/1KG4?
The INA111AU/1KG4 supports RG down to 4.99 Ω (G = 10,000), but stability requires careful layout: keep RG leads short, avoid sockets, and use 1% metal-film resistors. Values <100 Ω increase sensitivity to parasitic resistance; for G ≥ 100, RG ≤ 511 Ω demands PCB trace resistance <0.1 Ω. TI recommends verifying phase margin with a 100 pF capacitive load if RG < 100 Ω.
Does the INA111AU/1KG4 include ESD protection, and what precautions are needed?
Yes - the INA111AU/1KG4 incorporates on-chip ESD protection diodes rated for ±2 kV HBM, but it remains sensitive to handling damage. Burr-Brown explicitly warns that improper handling can cause subtle parametric shifts (e.g., increased IB or degraded CMRR) or catastrophic failure. Always use grounded wrist straps, conductive foam, and ESD-safe workstations; avoid touching pins directly, and verify functionality after board assembly.
INA111AU/1KG4 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 16-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Discontinued at Digi-Key
- 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/1KG4 FAQ
1.How can I place an order for INA111AU/1KG4 through Aetrix?
Please submit a Request for Quotation (RFQ) for INA111AU/1KG4 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/1KG4 reliable?
The price and inventory of INA111AU/1KG4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for INA111AU/1KG4 is usually 5 days.
3.What payment methods are accepted for INA111AU/1KG4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for INA111AU/1KG4 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for INA111AU/1KG4?
INA111AU/1KG4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your INA111AU/1KG4 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/1KG4?
For technical support, including INA111AU/1KG4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your INA111AU/1KG4 requirements.
6.How does Aetrix verify that INA111AU/1KG4 is sourced from the original manufacturer or authorized distributors?
All INA111AU/1KG4 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/1KG4 meets industry standards.
7.What is the process for return or replacement of INA111AU/1KG4?
All INA111AU/1KG4 units undergo pre-shipment inspection (PSI). If there is an issue with INA111AU/1KG4, 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/1KG4 part is unused and in its original packaging.
Return procedure for INA111AU/1KG4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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