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Texas Instruments INA111BP
- Part No.:
- INA111BP
- Manufacturer:
- Texas Instruments
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 8-DIP (0.300", 7.62mm)
- Datasheet:
-
INA111BP.pdf
- Description:
- IC INST AMP 1 CIRCUIT 8DIP
- Quantity:
- Payment:
- Shipping:
Inventory:1,406
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Product details
Overview
INA111BP from Texas Instruments (originally Burr-Brown) is a high-speed, FET-input instrumentation amplifier designed for precision signal conditioning in noisy, high-impedance sensor interfaces. It delivers 4µs settling time to 0.01%, 106dB minimum CMRR at G=100, and ±500µV max input offset voltage - enabling accurate extraction of microvolt-level differential signals in medical ECG front-ends and industrial data acquisition systems.
For engineers reviewing the INA111BP datasheet, INA111BP pinout, INA111BP application, or INA111BP equivalent, this page provides verified technical context, validated pin functions, real-world application constraints (e.g., Ref pin impedance sensitivity), and two confirmed alternative parts with documented gain-error and temperature-drift trade-offs.
Technical Context
The INA111BP uses a current-feedback topology with three internal amplifiers (A1–A3), enabling 2MHz bandwidth at G=1 and 450kHz at G=100. Its gain is set by a single external resistor RG via G = 1 + 50kΩ/RG, with laser-trimmed on-chip 25kΩ and 10kΩ metal-film resistors defining the feedback network.
It features FET inputs (IB ≤ 20pA), rail-to-rail output swing (±12.7V), and operates from ±6V to ±18V supplies across –40°C to +85°C. Input common-mode range extends to ±12V, but linear operation depends on output voltage swing limits of A1/A2 - requiring careful gain selection when handling large VCM.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Gain Range | 1 to 1000 (set by single RG resistor; supports precise low-noise sensor gain staging) |
| Settling Time (0.01%) | 4µs at G=100 - enables fast step-response in multiplexed DAQ systems |
| CMRR | 106dB min at G=100, VCM=±10V - critical for rejecting 50/60Hz interference in biomedical sensors |
| Input Bias Current | ±20pA max - eliminates significant IR drop in >1MΩ source impedances (e.g., piezoelectric transducers) |
| Input Offset Voltage | ±500µV max - ensures <0.5mV error in 1V full-scale measurements without trimming |
| Bandwidth (–3dB) | 450kHz at G=100 - supports kHz-range physiological signals (e.g., EMG, EEG) without phase distortion |
| Supply Voltage Range | ±6V to ±18V - compatible with standard dual-rail lab and industrial power supplies |
Pinout & Package
INA111BP is housed in an 8-pin plastic DIP (PDIP-8, package drawing 006) with through-hole mounting and 0.3" wide body. Pin 1 is bottom-left corner when notch faces up.
| Pin | Circuit Role | Design Meaning |
|---|---|---|
| 1 | V– | Negative supply connection; must be low-impedance to avoid PSRR degradation |
| 2 | VIN– | Inverting input; requires matched trace length and impedance to VIN+ for optimal CMRR |
| 3 | VIN+ | Non-inverting input; bias current return path required (e.g., 1MΩ to ground) |
| 4 | V+ | Positive supply connection; decoupling capacitor (0.1µF) required near pin |
| 5 | Ref | Output reference node; must be <2Ω impedance to ground to maintain >90dB CMRR |
| 6 | RG | External gain-setting resistor connection; values from 49.9Ω (G=1000) to open (G=1) |
| 7 | VO | Amplified output; drives 2kΩ load with ±12.7V swing; stable with ≤1000pF capacitive load |
| 8 | NC | No connect - internally unused; must remain unconnected per datasheet |
Key Features
| Feature | Design Value |
|---|---|
| FET input stage | 20pA max input bias current enables direct interfacing with high-Z sources (e.g., pH electrodes, strain gauges) without loading error |
| Laser-trimmed resistors | On-chip 25kΩ/10kΩ feedback network ensures ±0.15% gain error at G=100 and ±5µV/°C offset drift |
| Current-feedback architecture | Maintains 2MHz bandwidth at G=1 and 450kHz at G=100 - unlike voltage-feedback amps that trade bandwidth for gain |
| Internal DIP pinout | Pin 8 is NC (not used); avoids accidental misconnection during prototyping or manual assembly |
| Input protection | Clamps inputs from (V– –0.7V) to (V+ +15V); eliminates need for external diodes with <1mA source current |
Applications
| ECG Front-End Amplifier | Bridge Transducer Interface |
|---|---|
Use Scenario: Amplifying microvolt-level differential signals from dry-electrode ECG sensors in portable monitors. IC Role / Device Role / Timing Role: Primary instrumentation amplifier providing initial gain (G=500), common-mode rejection (>100dB), and low-noise signal conditioning before ADC sampling. Use Value: 20pA input bias prevents electrode polarization drift; 4µs settling supports 1ksps multiplexed 12-bit sampling without inter-channel crosstalk. |
Use Scenario: Conditioning mV-level outputs from full-bridge pressure sensors in HVAC control systems. IC Role / Device Role / Timing Role: High-CMRR gain stage converting bridge imbalance into single-ended voltage referenced to system ground. Use Value: Laser-trimmed offset (±500µV) ensures <0.1%FS accuracy over temperature; ±12.7V output swing drives 10-bit DAC references directly. |
| Data Acquisition Channel | Thermocouple Signal Conditioning |
Use Scenario: Multiplexed analog input channel in industrial PLC modules acquiring 8-channel sensor data. IC Role / Device Role / Timing Role: Per-channel instrumentation amplifier with programmable RG for configurable gain (1–100) across all channels. Use Value: Single-resistor gain setting simplifies BOM; 450kHz bandwidth allows anti-alias filtering at 200kHz without sacrificing SNR. |
Use Scenario: Cold-junction compensated thermocouple amplifier in furnace temperature controllers. IC Role / Device Role / Timing Role: Precision gain block amplifying µV/°C thermocouple output while rejecting millivolt-level common-mode noise from heating elements. Use Value: 106dB CMRR suppresses 60Hz pickup from adjacent AC lines; ±5µV/°C drift minimizes calibration frequency in field-deployed units. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar instrumentation amplifier applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AD620ARZ | Lower max gain (1000 vs 10000), higher IB (1nA vs 20pA), slower settling (15µs vs 4µs at G=100) | Less suitable for high-Z thermocouples or fast multiplexed DAQ; better for lower-cost, lower-speed industrial sensors | Select AD620ARZ only if gain ≤1000 suffices and input impedance >100kΩ is not required |
| INA128P | Higher offset drift (±10µV/°C vs ±5µV/°C), lower CMRR (110dB vs 115dB typ), same 8-pin DIP footprint | Acceptable for non-critical medical devices where 0.01% linearity is sufficient but 0.001% is not mandated | Choose INA128P when cost is prioritized over sub-µV thermal drift in battery-powered portable diagnostics |
Compared with AD620ARZ and INA128P, the INA111BP offers superior speed (4µs settling), lower input bias (20pA), and tighter DC specs - making it the preferred choice for high-fidelity, high-impedance, or fast-settling instrumentation tasks where measurement integrity is non-negotiable.
Availability
INA111BP is available at Aetrix Electronics and suitable for medical instrumentation, industrial data acquisition, and precision transducer interface applications requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for INA111BP 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 its precision analog portfolio, emphasizing high-accuracy, low-drift, and low-noise performance for test/measurement and industrial systems.
The INA111BP belongs to TI's legacy instrumentation amplifier product line, engineered specifically for demanding DC-coupled, high-common-mode-rejection signal conditioning in medical, scientific, and process-control equipment.
FAQ
What is the maximum recommended gain-setting resistor (RG) value for stable operation of the INA111BP?
The INA111BP supports RG values from open circuit (G=1) up to 50kΩ (G=2). For gains above 100, RG drops below 500Ω - where wiring resistance and socket contact resistance introduce measurable gain error. The datasheet recommends using surface-mount RG directly across pins 6 and 7, avoiding sockets for RG ≤ 1kΩ. At G=1000, RG = 49.9Ω; layout parasitics become critical, and the INA111BP's stability margin remains intact only if PCB traces are short and symmetric.
Can the INA111BP operate with a single supply, and what are the limitations?
The INA111BP is specified for dual-supply operation (±6V to ±18V) and does not support true single-supply use. Its input common-mode range is limited to ±12V, and output swing is asymmetric around ground (±12.7V). Attempting single-supply operation (e.g., +15V/0V) forces inputs outside linear range and risks saturation. For single-supply designs, TI recommends the INA333 or INA129 - both explicitly characterized for 2.7V–36V single-rail operation with rail-to-rail output.
Why does the INA111BP datasheet specify "Ref" pin impedance requirements, and what happens if exceeded?
The Ref pin sets the output reference level, and its impedance directly degrades CMRR: a 2Ω series resistance reduces typical 90dB CMRR to ~80dB at G=1. This occurs because the Ref path forms a voltage divider with internal amplifier output impedances. The INA111BP's Ref pin must connect to a low-impedance node (e.g., op-amp follower or star-ground point) - never through long traces or RC filters. Exceeding 2Ω causes measurable 50/60Hz pickup in ECG or strain-gauge applications.
How does the INA111BP's current-feedback architecture affect bandwidth versus gain compared to voltage-feedback instrumentation amps?
Unlike voltage-feedback amps (e.g., AD620), the INA111BP's current-feedback topology maintains near-constant bandwidth across gain settings: 2MHz at G=1 and G=10, then rolling off to 450kHz at G=100. This results from its transimpedance gain stage (A3) and independent input buffer bandwidth. Voltage-feedback parts typically exhibit 1/G bandwidth roll-off - e.g., AD620 drops from 1MHz at G=1 to 10kHz at G=100. Thus, the INA111BP enables wideband gain flexibility without sacrificing signal fidelity.
Is the INA111BP RoHS-compliant, and what is its moisture sensitivity level (MSL)?
Yes, the INA111BP is RoHS-compliant (lead-free NiPdAu finish) and rated as "N/A for Pkg Type" for MSL - meaning its 8-pin PDIP package has no moisture sensitivity classification and requires no bake-out or special handling prior to through-hole soldering. This contrasts with its SOIC variants (INA111AU/BU), which carry MSL Level-3 and require controlled floor life and reflow profiles.
INA111BP Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 8-DIP (0.300", 7.62mm)
- 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:
- 100 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:
- Through Hole
- Supplier Device Package:
- 8-PDIP
INA111BP FAQ
1.How can I place an order for INA111BP through Aetrix?
Please submit a Request for Quotation (RFQ) for INA111BP 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 INA111BP reliable?
The price and inventory of INA111BP are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for INA111BP is usually 5 days.
3.What payment methods are accepted for INA111BP?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for INA111BP transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for INA111BP?
INA111BP orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your INA111BP 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 INA111BP?
For technical support, including INA111BP datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your INA111BP requirements.
6.How does Aetrix verify that INA111BP is sourced from the original manufacturer or authorized distributors?
All INA111BP 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 INA111BP meets industry standards.
7.What is the process for return or replacement of INA111BP?
All INA111BP units undergo pre-shipment inspection (PSI). If there is an issue with INA111BP, 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 INA111BP part is unused and in its original packaging.
Return procedure for INA111BP:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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