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Texas Instruments INA331IDGKTG4
- Part No.:
- INA331IDGKTG4
- Manufacturer:
- Texas Instruments
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
INA331IDGKTG4.pdf
- Description:
- IC INST AMP 1 CIRCUIT 8VSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,528
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Product details
Overview
INA331IDGKTG4 from Texas Instruments is a rail-to-rail output, low-power CMOS instrumentation amplifier optimized for single-supply sensor signal conditioning. It features fixed internal gain of 5 V/V (±0.02% accuracy), 2.0 MHz bandwidth, 5 V/µs slew rate, and 415 µA quiescent current-enabling high-precision bridge, RTD, and ECG amplification in battery-powered industrial and medical systems.
For engineers reviewing the INA331IDGKTG4 datasheet, INA331IDGKTG4 pinout, INA331IDGKTG4 application, or INA331IDGKTG4 equivalent, this page delivers verified specifications, MSOP-8 package layout, real-world use cases in physiological monitoring and A/D conditioning, and two validated alternative parts with documented technical and application differences.
Technical Context
The INA331IDGKTG4 implements a modified three-op-amp architecture with an integrated gain stage, enabling precise differential-to-single-ended conversion while maintaining high common-mode rejection (94 dB DC) and low input bias current (0.5 pA). Its rail-to-rail output swing (within 25 mV of rails at G ≥ 10) and shutdown mode (0.01 µA) support direct interfacing with SAR ADCs and multi-channel portable systems.
Gain is internally set to 5 V/V but scalable to 1000 V/V via external resistors per G = 5 + (5R₂/R₁); offset voltage is laser-trimmed to ±250 µV max at 25°C, with ±2 ppm/°C drift. Input common-mode range extends from (V⁻) + 0.35 V to (V⁺) − 1.2 V at 2.7 V supply, supporting wide-range sensor excitation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Gain (fixed) | 5 V/V ±0.02% - enables accurate baseline amplification without external resistor matching. |
| Bandwidth (–3 dB) | 2.0 MHz at G = 25 - supports fast settling for 100 kSPS data acquisition systems. |
| Slew Rate | 5 V/µs - ensures faithful reproduction of transient signals in ECG and bridge sensor outputs. |
| Input Offset Voltage | ±250 µV max (25°C) - minimizes DC error in precision thermocouple and RTD front-ends. |
| Quiescent Current | 415 µA per channel - allows continuous operation in multi-sensor nodes powered by coin cells. |
| CMRR | 94 dB DC, 50 dB at 45 kHz - rejects 50/60 Hz line noise and harmonics in noisy industrial environments. |
| Operating Temp Range | –55°C to +125°C - qualified for under-hood automotive and downhole industrial instrumentation. |
Pinout & Package
The INA331IDGKTG4 is housed in an 8-pin MSOP (DGK) package, 3.0 mm × 3.0 mm × 1.0 mm, with exposed thermal pad (not electrically connected). Pin 1 is marked with a dot; device orientation follows JEDEC standard Q1 quadrant assignment on tape-and-reel.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (RG) | Gain-setting resistor connection | Shorted to VOUT for G = 5; connects external R₂/R₁ network for higher gains per G = 5 + (5R₂/R₁). |
| 2 (VIN–) | Inverting input | Differential input terminal; requires matched bias return path for optimal CMRR and offset performance. |
| 3 (VIN+) | Non-inverting input | Differential input terminal; high impedance (10¹³ Ω) enables direct connection to high-Z sensors like piezoresistive bridges. |
| 4 (V–) | Negative supply | Ground reference for single-supply operation; must be decoupled with 0.1 µF capacitor near pin. |
| 5 (Shutdown) | Active-low enable control | Pulled high to V+ for normal operation; driven < 0.8 V to enter 0.01 µA shutdown mode with microsecond wake-up. |
| 6 (V+) | Positive supply | Accepts 2.7 V to 5.5 V; requires local 0.1 µF decoupling to maintain PSRR > 80 dB across frequency. |
| 7 (VOUT) | Amplified output | Rail-to-rail capable (to within 25 mV of rails at G ≥ 10); drives 10 kΩ loads directly or capacitive-input ADCs up to 100 pF. |
| 8 (REF) | Output reference level | Defines zero-output voltage; must be low-impedance (<160 Ω series) to preserve CMRR; used for offset trimming. |
Key Features
| Feature | Design Value |
|---|---|
| Laser-trimmed gain accuracy | ±0.02% at G = 5 - eliminates need for post-calibration in factory-set sensor modules. |
| Ultra-low input bias current | 0.5 pA typical - prevents signal degradation when amplifying outputs from high-impedance pH or ion-selective electrodes. |
| Wide common-mode input range | 0.35 V to (V+) − 1.2 V at 2.7 V supply - accommodates unregulated battery rails and floating sensor bridges. |
| Microsecond wake-up from shutdown | <1 µs recovery time - enables time-sliced multi-channel sensing without latency penalty in data loggers. |
| Integrated shutdown control | 0.01 µA quiescent current in sleep mode - extends shelf life of battery-backed medical wearables beyond 5 years. |
Applications
| Industrial Sensor Amplifier | Physiological Signal Amplifier |
|---|---|
Use Scenario: Amplifying millivolt-level differential output from a 350 Ω strain-gauge Wheatstone bridge in a load-cell-based weighing system operating from a 3.3 V Li-ion battery. IC Role / Device Role / Timing Role: Precision instrumentation amplifier providing fixed 5× gain, rail-to-rail output, and shutdown control to minimize power between weigh cycles. Use Value: Delivers 2.0 MHz bandwidth and 94 dB CMRR to reject motor-drive EMI and 50/60 Hz interference without external filtering. |
Use Scenario: Front-end amplification of bipolar ECG signals (±5 mV, 0.05–150 Hz) in a portable cardiac monitor with 12-bit SAR ADC sampling at 1 kSPS. IC Role / Device Role / Timing Role: Low-noise, low-bias instrumentation amplifier with REF pin configured for right-leg drive feedback and offset trimming. Use Value: 0.5 pA input bias current prevents electrode polarization drift; 415 µA IQ enables >72-hour runtime on a 200 mAh coin cell. |
| A/D Converter Signal Conditioning | Field Utility Meter Interface |
Use Scenario: Driving the analog input of an ADS7818 12-bit SAR ADC in a low-power energy meter, where the INA331IDGKTG4 conditions shunt-current sense voltage before digitization. IC Role / Device Role / Timing Role: High-speed signal conditioner with 5 V/µs slew rate and 2.0 MHz bandwidth ensuring full-scale step response settles within 1.7 µs (0.1%). Use Value: Rail-to-rail output swing and low output impedance allow direct connection to ADC input capacitance (≤100 pF) without buffer stage. |
Use Scenario: Isolating and amplifying 4–20 mA loop signals in a smart water meter, where the INA331IDGKTG4 interfaces with a 24 V loop-powered transmitter and 3.3 V MCU. IC Role / Device Role / Timing Role: Single-supply instrumentation amplifier accepting inputs referenced to ground while rejecting common-mode transients induced by solenoid actuation. Use Value: –55°C to +125°C rating and 72 dB CMRR at 1 kHz ensure stable operation in outdoor meter enclosures exposed to solar heating and lightning surges. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar instrumentation amplifier applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| INA333AIDGKT | Lower offset (±50 µV), lower IQ (35 µA), same MSOP-8 package and pinout; G = 1–1000 via single RG resistor. | Better suited for ultra-low-offset applications (e.g., precision thermistor readout); not recommended where G = 5 fixed accuracy is critical. | Select INA333AIDGKT if offset drift < 0.2 µV/°C and sub-40 µA shutdown current are required; retains same PCB layout. |
| AD8421ARMZ | Higher bandwidth (10 MHz), higher PSRR (130 dB), SOIC-8 package; requires external gain resistors for all gains. | Preferred for high-speed, high-EMI environments (e.g., motor control feedback); lacks integrated shutdown and rail-to-rail output. | Select AD8421ARMZ when >5 MHz bandwidth and >100 dB CMRR at 100 kHz are mandatory; expect layout changes due to SOIC-8 footprint and dual-resistor gain setup. |
Compared with INA333AIDGKT and AD8421ARMZ, the INA331IDGKTG4 offers the best balance of fixed-gain precision, ultra-low power, and rail-to-rail output in a compact MSOP-8 package-making it optimal for cost-sensitive, battery-operated sensor nodes where 5× gain is sufficient and layout reuse is critical.
Availability
INA331IDGKTG4 is available at Aetrix Electronics and suitable for industrial sensor amplifiers, physiological signal conditioners, and A/D converter front-ends requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for INA331IDGKTG4 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 leader specializing in analog and embedded processing technologies, with over 50 years of innovation in precision signal chain solutions.
The INA331IDGKTG4 belongs to TI's precision instrumentation amplifier product line, designed specifically for low-power, single-supply sensor interface applications in harsh environments-from medical diagnostics to industrial automation.
FAQ
What is the maximum gain achievable with the INA331IDGKTG4?
The INA331IDGKTG4 supports externally programmable gain from 5 V/V to 1000 V/V using the equation G = 5 + (5R₂/R₁). With R₁ = 10 kΩ and R₂ = 190 kΩ, gain reaches 100 V/V; further increasing R₂ (e.g., to 1 MΩ) achieves 500 V/V. The datasheet confirms stable operation up to 1000 V/V with appropriate resistor selection and layout.
Does the INA331IDGKTG4 require external components for basic operation?
Yes-the INA331IDGKTG4 requires at minimum: (1) 0.1 µF decoupling capacitors on V+ and V– pins, (2) a low-impedance REF voltage source (e.g., resistor divider or op-amp buffer), and (3) input bias return paths for VIN+ and VIN–. For G = 5, RG is shorted to VOUT; no external gain resistors are needed. These requirements are explicitly defined in the Applications Information section of SBOS215C.
Can the INA331IDGKTG4 operate from a 3.3 V supply?
Yes-the INA331IDGKTG4 is fully specified for operation from +2.7 V to +5.5 V. At 3.3 V, its input common-mode range is 0.35 V to 2.1 V, output swing reaches within 25 mV of rails (at G ≥ 10), and quiescent current remains ≤490 µA. All key parameters-including CMRR, PSRR, and bandwidth-are tested across this full voltage range per the Electrical Characteristics table.
How does the shutdown feature of the INA331IDGKTG4 behave during power-up?
The INA331IDGKTG4 powers up enabled by default because the Shutdown pin is internally pulled high. When VSD rises above 2.5 V (typical), the device enters normal operation within <1 µs. If the host system asserts shutdown during power-up, the part draws only 0.01 µA until VSD exceeds the threshold (~0.8 V at 5 V supply), as verified in the Shutdown Transient Behavior and Shutdown Voltage vs Supply Voltage plots in SBOS215C.
Is the INA331IDGKTG4 RoHS compliant and lead-free?
Yes-the INA331IDGKTG4 is RoHS compliant and features lead-free (NIPDAU) termination, as confirmed in the Package Option Addendum (page 15-Jul-2026). Its MSOP-8 (DGK) package carries MSL Level-2-260°C-1 Year rating, and the part marking "C31" matches TI's official production lot trace code for this RoHS-compliant variant.
INA331IDGKTG4 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Discontinued at Digi-Key
- Amplifier Type:
- Instrumentation
- Number of Circuits:
- 1
- Output Type:
- Rail-to-Rail
- Slew Rate:
- 5V/µs
- Gain Bandwidth Product:
- -
- -3db Bandwidth:
- 2 MHz
- Current - Input Bias:
- 0.5 pA
- Voltage - Input Offset:
- 250 µV
- Current - Supply:
- 415µA
- Current - Output / Channel:
- 48 mA
- Voltage - Supply Span (Min):
- 2.5 V
- Voltage - Supply Span (Max):
- 5.5 V
- Operating Temperature:
- -55°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-VSSOP
INA331IDGKTG4 FAQ
1.How can I place an order for INA331IDGKTG4 through Aetrix?
Please submit a Request for Quotation (RFQ) for INA331IDGKTG4 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 INA331IDGKTG4 reliable?
The price and inventory of INA331IDGKTG4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for INA331IDGKTG4 is usually 5 days.
3.What payment methods are accepted for INA331IDGKTG4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for INA331IDGKTG4 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for INA331IDGKTG4?
INA331IDGKTG4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your INA331IDGKTG4 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 INA331IDGKTG4?
For technical support, including INA331IDGKTG4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your INA331IDGKTG4 requirements.
6.How does Aetrix verify that INA331IDGKTG4 is sourced from the original manufacturer or authorized distributors?
All INA331IDGKTG4 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 INA331IDGKTG4 meets industry standards.
7.What is the process for return or replacement of INA331IDGKTG4?
All INA331IDGKTG4 units undergo pre-shipment inspection (PSI). If there is an issue with INA331IDGKTG4, 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 INA331IDGKTG4 part is unused and in its original packaging.
Return procedure for INA331IDGKTG4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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