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Texas Instruments INA111AP
- Part No.:
- INA111AP
- Manufacturer:
- Texas Instruments
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 8-DIP (0.300", 7.62mm)
- Datasheet:
-
INA111AP.pdf
- Description:
- IC INST AMP 1 CIRCUIT 8DIP
- Quantity:
- Payment:
- Shipping:
Inventory:122
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Product details
Overview
INA111AP from Texas Instruments (formerly 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% at G=100, 106dB minimum CMRR at G=100, and ±500µV max input offset voltage - enabling accurate extraction of low-level biomedical or industrial transducer signals.
For engineers reviewing the INA111AP datasheet, INA111AP pinout, INA111AP application, or INA111AP equivalent, key selection considerations include its current-feedback topology for wide bandwidth (2MHz at G=1), laser-trimmed DC accuracy, 8-pin PDIP package with internal DIP-connected gain-setting resistor network, and suitability for medical instrumentation, data acquisition, and bridge sensor amplification where input bias current <20pA and fast settling are critical.
Technical Context
The INA111AP employs a three-op-amp current-feedback architecture with internally connected 10kΩ/25kΩ resistor networks, enabling extended bandwidth and predictable gain-phase response. Its FET-input stage achieves 10¹²Ω input impedance and ±20pA max input bias current, reducing errors from high-Z sources and simplifying RC filter design without offset drift.
Gain is set by a single external resistor RG per G = 1 + 50kΩ/RG, supporting 1–10,000× range. The device operates from ±6V to ±18V supplies, specified over –40°C to +85°C, with output swing up to ±12.7V into 2kΩ load and 17V/µs slew rate - optimized for dynamic, wide-gain-range instrumentation front-ends.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Gain Bandwidth | 2MHz at G=1; enables fast step response in unity-gain buffer or low-gain signal routing |
| Settling Time | 4µs to 0.01% at G=100; supports high-throughput data acquisition with minimal dead time |
| CMRR | 106dB min at G=100; rejects common-mode noise from long sensor cables in ECG or strain gauge systems |
| Input Offset Voltage | ±500µV max; ensures sub-mV error in 10mV full-scale sensor outputs without trimming |
| Input Bias Current | ±20pA max; eliminates significant voltage drop across >1MΩ source impedances (e.g., pH electrodes) |
| Supply Range | ±6V to ±18V; accommodates legacy ±15V rails and modern ±12V industrial power domains |
| Operating Temp | –40°C to +85°C; qualified for industrial and medical equipment deployed in uncontrolled environments |
Pinout & Package
INA111AP is housed in an 8-pin plastic DIP (PDIP) package with 0.3-inch width, compatible with standard through-hole prototyping and production PCBs. Pin 1 is bottom-left corner when notch faces up; leads are tin-lead (NIPDAU) finish, RoHS-compliant.
| Pin | Circuit Role | Design Meaning |
|---|---|---|
| 1 | V– | Negative supply rail connection; must be decoupled locally to minimize PSRR degradation |
| 2 | VIN– | Inverting input terminal; forms differential pair with Pin 3; requires matched trace routing for CMR integrity |
| 3 | VIN+ | Non-inverting input terminal; high-impedance FET node; needs bias current return path (e.g., matched resistors to ground) |
| 4 | RG | External gain-setting resistor connection; ties to internal 50kΩ feedback sum; determines G = 1 + 50kΩ/RG |
| 5 | Ref | Output reference node; sets output common-mode level; must be low-impedance (≤2Ω) to preserve CMRR |
| 6 | VO | Amplified output; drives loads ≥2kΩ; stability requires ≤1000pF capacitive loading unless compensated |
| 7 | V+ | Positive supply rail connection; decoupling capacitor required adjacent to pin for high-frequency PSRR |
| 8 | NC | No connect; internally unused; must remain floating or grounded per layout best practices |
Key Features
| Feature | Design Value |
|---|---|
| FET Input Stage | 10¹²Ω input impedance and ≤20pA bias current enable direct interfacing with piezoelectric sensors and high-resistance electrodes without signal loss |
| Current-Feedback Topology | Delivers flat 2MHz bandwidth at G=1 and maintains usable bandwidth up to G=1000 (50kHz), unlike voltage-feedback amplifiers whose bandwidth collapses with gain |
| Laser-Trimmed Resistors | On-chip 50kΩ metal-film network trimmed for ±0.15% gain error at G=100, eliminating need for external calibration in production systems |
| 0.01% Settling Time | 4µs at G=100 allows 250kSPS sampling in multiplexed DAQ systems with 16-bit resolution retention |
| High CMRR Stability | 106dB minimum at G=100 and maintained above 90dB up to 10kHz, ensuring robust rejection of 50/60Hz mains interference in clinical monitors |
Applications
| ECG Signal Conditioning | Strain Gauge Bridge Amplification |
|---|---|
Use Scenario: Amplifying microvolt-level differential cardiac signals from dry-electrode chest leads in portable ECG devices. IC Role / Device Role / Timing Role: Primary front-end instrumentation amplifier providing programmable gain (G=100–500), high CMRR, and ultra-low input current to prevent electrode polarization. Use Value: Enables clean acquisition of P/QRS/T waveforms with <1µV RMS noise floor, meeting AHA diagnostic fidelity requirements without active guarding. | Use Scenario: Reading millivolt outputs from 350Ω foil strain gauges in structural health monitoring sensors exposed to temperature swings. IC Role / Device Role / Timing Role: Precision bridge amplifier with gain set by 511Ω RG for G=100, rejecting common-mode thermal EMFs and lead resistance variations. Use Value: Delivers <0.01% nonlinearity and ±5µV/°C offset drift, allowing ±0.1% full-scale accuracy across –25°C to +70°C ambient without recalibration. |
| Data Acquisition Channel Front-End | Thermocouple Cold-Junction Compensation |
Use Scenario: Multiplexed 12-bit ADC input stage handling 8 channels of mixed-signal industrial sensors (RTDs, pressure transducers, flow meters). IC Role / Device Role / Timing Role: Channel-selectable instrumentation amplifier with fast settling (4µs) and rail-to-rail output swing to maximize ADC dynamic range utilization. Use Value: Supports 250kSPS aggregate throughput while maintaining 16-bit effective resolution via 0.01% settling and low THD+N (0.001% at 1kHz). | Use Scenario: Amplifying Type-K thermocouple outputs (≈41µV/°C) referenced to a local cold-junction sensor in oven temperature controllers. IC Role / Device Role / Timing Role: Low-drift, high-Z amplifier with G=500 (RG=100Ω) to boost µV signals above ADC noise floor while rejecting common-mode noise from heater switching. Use Value: Achieves ±0.5°C measurement accuracy from 0°C to 1000°C using only laser-trimmed on-die offset compensation, no external trim pots. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar instrumentation amplifier applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| INA128P | Lower input bias current (±2pA), higher CMRR (120dB), but slower settling (10µs at G=100); uses voltage-feedback topology | Better for ultra-high-Z pH or ion-selective electrodes; less suitable for >100kSPS DAQ due to longer settling | Select INA128P when DC precision dominates speed; choose INA111AP when bandwidth and settling time are critical |
| AD620ANZ | Higher gain error (±0.2% at G=100), wider offset drift (±1µV/°C), but lower cost and same 8-pin DIP footprint | Suitable for cost-sensitive industrial controls where ±0.02% linearity suffices; lacks INA111AP's 2MHz GBW | Use AD620ANZ for budget-constrained designs accepting 5× slower settling; retain INA111AP for medical-grade timing fidelity |
Compared with INA128P and AD620ANZ, the INA111AP uniquely balances 2MHz bandwidth, 4µs settling, and laser-trimmed DC accuracy in an 8-pin DIP - making it optimal for high-speed, high-precision sensor front-ends where both dynamic response and low drift are mandatory.
Availability
INA111AP is available at Aetrix Electronics and suitable for medical instrumentation, industrial data acquisition, and precision transducer signal conditioning requiring stable component supply across long-lifecycle OEM programs.
Supply support for INA111AP 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, renowned for high-performance op amps, data converters, and interface ICs serving industrial, medical, and test equipment markets.
The INA111 series was developed specifically for high-speed, low-drift instrumentation front-ends - targeting applications demanding simultaneous wide bandwidth, nanovolt-level offset stability, and femtoampere input bias current in compact DIP/SOIC packages.
FAQ
What is the maximum gain achievable with the INA111AP using an external resistor?
The INA111AP supports gains from 1 to 10,000 V/V via external resistor RG according to G = 1 + 50kΩ/RG. For G=10,000, RG = 5.001Ω (nearest 1% value: 4.99Ω). At this gain, bandwidth reduces to 50kHz and settling time increases to 30µs, but the INA111AP maintains functional operation with verified 0.04% nonlinearity. Designers must ensure RG's temperature coefficient and parasitic inductance do not degrade gain stability.
Does the INA111AP require external capacitors for power supply decoupling?
Yes, the INA111AP requires 0.1µF ceramic capacitors placed as close as possible to Pins 1 (V–) and 7 (V+), referenced to a low-impedance ground plane. This is mandatory to maintain specified PSRR (>100dB at 100Hz) and prevent oscillation from supply impedance interactions. Larger bulk capacitors (e.g., 10µF tantalum) may be added remotely, but the 0.1µF units must be within 2mm of the IC pins per TI layout guidelines.
Can the INA111AP drive capacitive loads directly, and what is the limit?
The INA111AP is stable with capacitive loads up to 1000pF when driving a 2kΩ load, as specified in the Absolute Maximum Ratings. Driving >1000pF risks peaking or oscillation; for heavier loads (e.g., ADC input capacitance + PCB trace), TI recommends isolating the output with a 10Ω–50Ω series resistor or using the SOIC version (INA111AU) with its dedicated output sense pin for remote feedback compensation.
How does the INA111AP handle input overvoltage conditions beyond its common-mode range?
The INA111AP inputs tolerate voltages from (V–) –0.7V to (V+) +15V. If common-mode voltage exceeds ±12V (linear range), A1/A2 input stages saturate, causing output to collapse near zero despite valid differential input - a failure mode requiring external clamping. For >1mA fault current, TI recommends 2N4117A diodes (low-leakage) with 10kΩ series resistors, as detailed in Figure 5 of the INA111AP datasheet.
Is the INA111AP pin-compatible with other Burr-Brown instrumentation amplifiers like the INA128?
No, the INA111AP is not pin-compatible with the INA128P. While both use 8-pin DIP packages, their pinouts differ fundamentally: INA111AP assigns Pin 4 to RG and Pin 5 to Ref, whereas INA128P uses Pin 4 for Ref and Pin 5 for RG. Swapping them causes incorrect gain setting and reference misconfiguration. Always verify pin mapping against the specific device's datasheet before PCB layout.
INA111AP 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:
- 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:
- Through Hole
- Supplier Device Package:
- 8-PDIP
INA111AP FAQ
1.How can I place an order for INA111AP through Aetrix?
Please submit a Request for Quotation (RFQ) for INA111AP 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 INA111AP reliable?
The price and inventory of INA111AP are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for INA111AP is usually 5 days.
3.What payment methods are accepted for INA111AP?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for INA111AP transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for INA111AP?
INA111AP orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your INA111AP 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 INA111AP?
For technical support, including INA111AP datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your INA111AP requirements.
6.How does Aetrix verify that INA111AP is sourced from the original manufacturer or authorized distributors?
All INA111AP 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 INA111AP meets industry standards.
7.What is the process for return or replacement of INA111AP?
All INA111AP units undergo pre-shipment inspection (PSI). If there is an issue with INA111AP, 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 INA111AP part is unused and in its original packaging.
Return procedure for INA111AP:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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