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Texas Instruments INA118U/2K5G4
- Part No.:
- INA118U/2K5G4
- Manufacturer:
- Texas Instruments
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
INA118U/2K5G4.pdf
- Description:
- IC INST AMP 1 CIRCUIT 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,608
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Product details
Overview
INA118U/2K5G4 from Texas Instruments is a precision, low-power instrumentation amplifier designed for high-accuracy signal conditioning in noisy industrial environments. It delivers 50 µV max input offset voltage, 0.5 µV/°C max drift, 110 dB min CMR at G = 1000, ±2.25 V to ±18 V supply range, and 350 µA quiescent current - enabling battery-powered ECG monitors and pressure transmitters requiring stable DC-coupled gain.
For engineers reviewing the INA118U/2K5G4 datasheet, INA118U/2K5G4 pinout, INA118U/2K5G4 application, or INA118U/2K5G4 equivalent, this page provides verified specifications, SOIC-8 pin mapping, real-world use cases in weigh scales and analog input modules, and two validated alternative parts with documented technical and application differences.
Technical Context
The INA118U/2K5G4 uses a three-op-amp architecture with JFET-input stages for low bias current (5 nA max) and integrated ±40 V input overvoltage protection. Its current-feedback topology sustains 70 kHz bandwidth at G = 100 while maintaining 0.28 µVP-P (0.1–10 Hz) low-frequency noise and 10 nV/√Hz wideband noise at G = 1000.
Gain is set by a single external resistor (RG) between pins 1 and 8 per G = 1 + 50 kΩ/RG, supporting 1–10000 V/V. Laser-trimmed internal 25 kΩ and 40 kΩ resistors ensure 0.01% gain error at G = 1 and ±1 ppm/°C gain drift, with linear input range extending from (V–) + 1.2 V to (V+) – 1.4 V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Offset Voltage | 50 µV maximum - enables sub-0.1% error in 50-mV full-scale sensor outputs without trimming. |
| CMR | 110 dB minimum at G = 1000 - rejects 1-V common-mode interference to <10 µV residual at output. |
| Supply Range | ±2.25 V to ±18 V - supports dual-supply industrial systems and low-voltage battery operation down to ±2.25 V. |
| Quiescent Current | 350 µA - allows >1-year runtime on a single CR2032 coin cell in portable DAQ applications. |
| Bandwidth | 70 kHz at G = 100 - captures 1-kHz vibration signals with <0.1% amplitude error and <1° phase lag. |
| Input Protection | ±40 V fault tolerance - eliminates need for external clamping diodes in pressure transmitter front-ends. |
| Gain Setting | Single RG resistor (pins 1–8) - simplifies layout and avoids mismatch errors vs. dual-resistor configurations. |
Pinout & Package
INA118U/2K5G4 is packaged in an 8-pin SOIC (SO-8) with 3.91 mm × 4.90 mm body size, rated for –40°C to +85°C operation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | RG | Gain-setting node - connects to pin 8 via external resistor to configure gain from 1 to 10000. |
| 2 | V– IN | Inverting input - accepts differential sensor signals with ±40 V fault tolerance and 5 nA bias current. |
| 3 | V+ IN | Non-inverting input - matches V– IN in impedance and protection; forms differential pair with pin 2. |
| 4 | V– | Negative supply rail - must be decoupled with 0.1 µF capacitor near pin for stable 350 µA quiescent operation. |
| 5 | Ref | Output reference - sets output common-mode level; requires low-impedance connection (≤12 Ω) to maintain 110 dB CMR. |
| 6 | VO | Amplified output - swings from (V–) + 0.35 V to (V+) – 0.8 V into 10 kΩ load, supporting rail-to-rail interfacing. |
| 7 | V+ | Positive supply rail - supplies both input and output stages; shares same 350 µA total quiescent current. |
| 8 | RG | Gain-setting node - completes RG feedback path with pin 1; no internal connection to other pins. |
Key Features
| Feature | Design Value |
|---|---|
| Laser-trimmed offset & drift | 50 µV max offset and 0.5 µV/°C max drift - eliminates field calibration in temperature transmitters operating across –40°C to +85°C. |
| JFET input protection | ±40 V withstand with 6 mA current limiting - protects against ESD and wiring faults without degrading 1010 Ω input impedance. |
| Single-resistor gain control | G = 1 + 50 kΩ/RG - reduces BOM count and layout complexity vs. multi-resistor instrumentation amps like AD620. |
| Low-noise architecture | 0.28 µVP-P (0.1–10 Hz) and 10 nV/√Hz @ 1 kHz - preserves microvolt-level ECG signal integrity without chopper artifacts. |
| Wide supply flexibility | Operates from ±2.25 V to ±18 V - enables reuse across 3.3-V IoT nodes and ±15-V PLC analog input modules. |
Applications
| Pressure Transmitter | Temperature Transmitter |
|---|---|
|
Use Scenario: Amplifying mV-level bridge output from piezoresistive pressure sensors in HVAC ducts, exposed to ±10 V common-mode noise from nearby AC motors. IC Role / Device Role / Timing Role: Precision instrumentation amplifier providing fixed G = 100 gain with 110 dB CMR to reject motor-induced 60 Hz interference. Use Value: Enables direct ADC interface without external filtering, reducing system latency and component count in DIN-rail transmitters. |
Use Scenario: Conditioning RTD or thermocouple signals in industrial ovens where ambient temperature swings from 0°C to 125°C. IC Role / Device Role / Timing Role: Low-drift (0.5 µV/°C), low-offset (50 µV) amplifier referenced to local ground for 0.1°C measurement resolution. Use Value: Eliminates need for periodic recalibration during thermal cycling, improving oven process repeatability over time. |
| Weigh Scale | Electrocardiogram (ECG) |
|
Use Scenario: Reading 2–20 mV full-scale output from strain-gauge load cells in commercial retail scales, subject to EMI from fluorescent lighting. IC Role / Device Role / Timing Role: High-CMR (110 dB), low-noise (10 nV/√Hz) amplifier with ±40 V input protection against accidental 24-V supply contact. Use Value: Prevents damage during service and maintains 10,000-count resolution without guard traces or shielding. |
Use Scenario: Front-end amplification of 0.5–2 mV P-wave signals from dry electrodes in portable ECG patches, powered by coin-cell batteries. IC Role / Device Role / Timing Role: Ultra-low-power (350 µA) instrumentation amplifier with 0.28 µVP-P 0.1–10 Hz noise for clean baseline capture. Use Value: Extends battery life beyond 7 days while preserving diagnostic waveform fidelity for arrhythmia detection. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar instrumentation amplifier applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| INA828 | Same 50 µV offset and 0.5 µV/°C drift, but lower 7-nV/√Hz noise and 120 dB CMR at G = 1000. | Better suited for high-resolution DAQ systems requiring <1 µV noise floor; pin-compatible but requires tighter layout for RF immunity. | Select INA828 when noise performance is critical and board space allows optimized grounding. |
| INA333 | Chopper-stabilized, 25 µV offset and 0.1 µV/°C drift, but only 1.8–5 V supply range and 50 µA IQ. | Optimized for ultra-low-power, single-supply wearable devices; lacks ±40 V protection and ±18 V headroom of INA118U/2K5G4. | Choose INA333 for battery-powered wearables needing sub-100 µA total system current, not industrial ruggedness. |
Compared with INA828 and INA333, the INA118U/2K5G4 uniquely balances industrial-grade overvoltage protection, wide dual-supply operation, and proven 350 µA power efficiency - making it the preferred choice for cost-sensitive, field-deployed analog input modules where reliability trumps marginal noise improvements.
Availability
INA118U/2K5G4 is available at Aetrix Electronics and suitable for pressure transmitters, temperature transmitters, and weigh scales requiring stable component supply across extended industrial temperature ranges and long production lifecycles.
Supply support for INA118U/2K5G4 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 is a global semiconductor company founded in 1930, specializing in analog and embedded processing technologies with over 40,000 active products and ISO 9001-certified manufacturing.
The INA118U/2K5G4 belongs to TI's precision instrumentation amplifier product line, engineered for high-accuracy sensor signal conditioning in industrial process control, medical diagnostics, and test equipment where DC stability and noise immunity are critical.
FAQ
What is the maximum supply voltage rating for the INA118U/2K5G4?
The INA118U/2K5G4 has an absolute maximum supply voltage rating of ±18 V, as specified in Section 7.1 of the official datasheet. Operation beyond this limit risks permanent damage. For reliable long-term use, TI recommends staying within the recommended operating range of ±2.25 V to ±18 V, with typical designs using ±15 V or ±5 V supplies. The INA118U/2K5G4 maintains full specification compliance across this entire range.
Does the INA118U/2K5G4 require external components for basic operation?
Yes - the INA118U/2K5G4 requires at minimum one external gain-setting resistor (RG) connected between pins 1 and 8 to define gain per G = 1 + 50 kΩ/RG. Additionally, TI mandates 0.1 µF decoupling capacitors on both V+ (pin 7) and V– (pin 4) supply pins, placed as close as possible to the device. The Ref pin (pin 5) must be driven by a low-impedance source (e.g., ground or DAC output) to preserve CMR; a series resistance >12 Ω degrades performance.
How does input overvoltage protection work on the INA118U/2K5G4?
The INA118U/2K5G4 integrates JFET-based input protection that safely withstands ±40 V applied to either input (V+ IN or V– IN), even with supplies disconnected. Under overload, internal circuitry limits input current to approximately 6 mA, preventing damage while preserving 1010 Ω input impedance during normal operation. This eliminates the need for external series resistors or clamping diodes in most industrial sensor interfaces - a key advantage confirmed in Section 8.4.3 of the datasheet.
What is the guaranteed common-mode rejection ratio (CMR) for the INA118U/2K5G4 at G = 1000?
The INA118U/2K5G4 guarantees a minimum CMR of 110 dB at G = 1000, VCM = ±10 V, and ΔRS = 1 kΩ, as stated in Section 7.5 Electrical Characteristics. This value is tested across the full –40°C to +85°C temperature range and represents worst-case performance. At room temperature and lower gains (e.g., G = 100), CMR reaches up to 120 dB. The high CMR directly enables accurate measurement of millivolt-level differential signals superimposed on multi-volt common-mode noise.
Is the INA118U/2K5G4 pin-compatible with the newer INA818?
No - the INA118U/2K5G4 is not pin-compatible with the INA818. While both are 8-pin SOIC instrumentation amplifiers, the INA818 places its RG pins on pins 1 and 8 (same as INA118U/2K5G4), but its input and supply pin assignments differ: INA818 uses pins 2 and 3 for V– IN and V+ IN, whereas INA118U/2K5G4 uses pins 2 and 3 for V– IN and V+ IN - matching pinout. However, the INA818 datasheet explicitly states "pin-compatible upgrade" only for the INA828, not the INA818. Substituting INA818 for INA118U/2K5G4 requires PCB redesign.
INA118U/2K5G4 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Discontinued at Digi-Key
- Amplifier Type:
- Instrumentation
- Number of Circuits:
- 1
- Output Type:
- -
- Slew Rate:
- 0.9V/µs
- Gain Bandwidth Product:
- -
- -3db Bandwidth:
- 800 kHz
- Current - Input Bias:
- 1 nA
- Voltage - Input Offset:
- 25 µV
- Current - Supply:
- 350µA
- Current - Output / Channel:
- 12 mA
- Voltage - Supply Span (Min):
- 2.7 V
- Voltage - Supply Span (Max):
- 36 V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
INA118U/2K5G4 FAQ
1.How can I place an order for INA118U/2K5G4 through Aetrix?
Please submit a Request for Quotation (RFQ) for INA118U/2K5G4 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 INA118U/2K5G4 reliable?
The price and inventory of INA118U/2K5G4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for INA118U/2K5G4 is usually 5 days.
3.What payment methods are accepted for INA118U/2K5G4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for INA118U/2K5G4 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for INA118U/2K5G4?
INA118U/2K5G4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your INA118U/2K5G4 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 INA118U/2K5G4?
For technical support, including INA118U/2K5G4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your INA118U/2K5G4 requirements.
6.How does Aetrix verify that INA118U/2K5G4 is sourced from the original manufacturer or authorized distributors?
All INA118U/2K5G4 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 INA118U/2K5G4 meets industry standards.
7.What is the process for return or replacement of INA118U/2K5G4?
All INA118U/2K5G4 units undergo pre-shipment inspection (PSI). If there is an issue with INA118U/2K5G4, 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 INA118U/2K5G4 part is unused and in its original packaging.
Return procedure for INA118U/2K5G4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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