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Texas Instruments INA331AIDGKRG4
- Part No.:
- INA331AIDGKRG4
- Manufacturer:
- Texas Instruments
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
INA331AIDGKRG4.pdf
- Description:
- IC INST AMP 1 CIRCUIT 8VSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,521
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Product details
Overview
INA331AIDGKRG4 from Texas Instruments is a rail-to-rail output, low-power CMOS instrumentation amplifier optimized for single-supply operation (2.7V to 5.5V), delivering 2.0MHz bandwidth, 5V/µs slew rate, and ±250µV input offset voltage. It features internal gain of 5V/V (0.02% accuracy), shutdown mode drawing only 0.01µA, and operates across –55°C to +125°C - ideal for precision sensor signal conditioning in battery-powered industrial and medical systems.
For engineers reviewing the INA331AIDGKRG4 datasheet, INA331AIDGKRG4 pinout, INA331AIDGKRG4 application, or INA331AIDGKRG4 equivalent, key selection criteria include its low quiescent current (415µA), high CMRR (94dB DC), 0.5pA input bias current, and MSOP-8 package compatibility with space-constrained PCB layouts.
Technical Context
The INA331AIDGKRG4 implements a modified two-op-amp instrumentation architecture with an integrated third gain stage, enabling precise differential-to-single-ended conversion while maintaining rail-to-rail output swing for gains ≥10. Its CMOS input stage delivers ultra-low input bias current (0.5pA typical) and high input impedance (10¹³ Ω || 3pF), making it suitable for high-impedance bridge and RTD sensors.
Gain is internally fixed at 5V/V but scalable to 1000V/V using external resistors per G = 5 + (5R₂/R₁); reference pin control allows output level shifting and offset trimming. Shutdown activation occurs when the SHUTDOWN pin drops below 0.8V (on 5V supply), reducing current to 0.01µA within nanoseconds and placing output in high-impedance state.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage Range | +2.7V to +5.5V - supports direct integration into 3.3V and 5V embedded systems without level-shifting. |
| Bandwidth (–3dB) | 2.0MHz at G = 25 - sufficient for driving sampling ADCs up to ~100kSPS with minimal settling error. |
| Input Offset Voltage | ±250µV max at TA = +25°C - enables accurate amplification of µV-level sensor outputs (e.g., load cells, thermocouples). |
| CMRR | 94dB at DC, 50dB at 45kHz - rejects line-frequency noise and harmonics in industrial EMI environments. |
| Quiescent Current | 415µA max per channel - extends battery life in portable ECG monitors and wireless sensor nodes. |
| Shutdown Current | 0.01µA - allows duty-cycled operation in multi-channel data acquisition systems without significant power penalty. |
| Input Bias Current | 0.5pA typical - prevents loading errors in high-Z sources like piezoelectric sensors or pH electrodes. |
| Operating Temperature | –55°C to +125°C - qualified for under-hood automotive and downhole industrial applications. |
Pinout & Package
INA331AIDGKRG4 is housed in an 8-pin MSOP (DGK) package - 3.0mm × 3.0mm footprint, 0.65mm pitch, 1.0mm height - optimized for compact, high-density PCB layouts.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - RG | Gain-setting resistor connection | Shorted to VOUT for G = 5; used with R₁/R₂ network to set G > 5 per G = 5 + (5R₂/R₁). |
| 2 - VIN– | Inverting input | Differential input terminal; requires matched bias current return path for optimal CMRR. |
| 3 - VIN+ | Non-inverting input | Differential input terminal; referenced to same common-mode potential as VIN– for rejection. |
| 4 - V– | Negative supply rail | Ground or negative rail connection; must be decoupled with 0.1µF capacitor near pin. |
| 5 - Shutdown | Enable/disable control | Pulled high to V+ for normal operation; driven <0.8V (5V supply) to enter sub-µA shutdown mode. |
| 6 - V+ | Positive supply rail | +2.7V to +5.5V supply; requires local 0.1µF ceramic decoupling for noise immunity. |
| 7 - VOUT | Amplified output | Rail-to-rail swing (to within 25mV of rails at RL ≥10kΩ); drives capacitive loads up to 100pF directly. |
| 8 - REF | Output reference level | Sets zero-output voltage; must be low-impedance (<160Ω series) to preserve 94dB CMRR. |
Key Features
| Feature | Design Value |
|---|---|
| Laser-trimmed gain accuracy | 0.02% error at G = 5 ensures stable calibration over temperature (2ppm/°C drift). |
| Rail-to-rail output stage | Swings to within 25mV of supply rails at light loads - eliminates need for dual supplies in single-ended ADC interfaces. |
| Ultra-low input bias current | 0.5pA typical enables use with >10MΩ source impedances (e.g., thermistors, pH probes) without signal degradation. |
| Integrated shutdown function | Nanosecond activation and microsecond wake-up support time-sliced multi-channel sensing with <1µA standby draw. |
| High-frequency CMRR retention | 50dB at 45kHz maintains noise rejection in switched-mode power supply environments and motor drive feedback loops. |
| Wide common-mode input range | 0.35V to 1.5V (at VS = 2.7V) and 0.55V to 3.8V (at VS = 5V) accommodates unregulated sensor excitation voltages. |
Applications
| Industrial Bridge Sensor Amplifier | Portable Medical ECG Front-End |
|---|---|
Use Scenario: Amplifying mV-level differential output from strain-gauge load cells in factory-floor weighing systems operating from 3.3V rails. IC Role / Device Role / Timing Role: Precision instrumentation amplifier providing fixed G = 5 gain, rejecting 50/60Hz line noise via 94dB CMRR, and driving 12-bit SAR ADC inputs. Use Value: Enables direct interface to low-voltage ADCs without external level-shifting; 415µA IQ supports always-on monitoring in energy-conscious IIoT nodes. | Use Scenario: Conditioning biopotential signals from limb electrodes in battery-powered fitness trackers with ECG capability. IC Role / Device Role / Timing Role: Low-noise, low-power front-end amplifier with shutdown control synchronized to heart-rate sampling intervals. Use Value: 0.5pA input bias current prevents electrode polarization errors; rail-to-rail output maximizes dynamic range into 3.3V ADCs. |
| Single-Supply Data Acquisition Channel | Field Utility Meter Analog Front-End |
Use Scenario: Signal conditioning stage in a 4-channel, 100kSPS data logger powered by coin-cell batteries. IC Role / Device Role / Timing Role: Differential amplifier with programmable gain (via external resistors) and microsecond-scale shutdown recovery for channel multiplexing. Use Value: 0.01µA shutdown current reduces average power by >99% during idle periods; 2.0MHz bandwidth supports anti-alias filtering before sampling. | Use Scenario: Isolated current/voltage sensing in smart electricity meters exposed to –40°C to +85°C ambient conditions. IC Role / Device Role / Timing Role: High-CMRR amplifier rejecting common-mode transients on shunt-based current measurement paths. Use Value: Specified operation to +125°C junction temperature ensures reliability in sealed meter enclosures; 72dB CMRR maintained over full temp range. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar instrumentation amplifier applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| INA333AIDGKR | Lower IQ (35µA vs 415µA), improved offset (±25µV), same MSOP-8 package and pinout. | Better suited for ultra-low-power, high-precision applications where sub-100µA total system current is critical. | Select INA333AIDGKR if offset drift and quiescent current are prioritized over cost and legacy design continuity. |
| AD8421ARMZ | Higher bandwidth (10MHz), higher supply range (±2.5V to ±18V), SOIC-8 package, no shutdown pin. | Preferred for bipolar-supply, high-speed applications (e.g., oscilloscope front-ends) requiring wider dynamic range. | Choose AD8421ARMZ when operating from dual supplies or needing >5× bandwidth; not drop-in due to different pinout and missing shutdown. |
Compared with INA333AIDGKR and AD8421ARMZ, the INA331AIDGKRG4 offers the best balance of cost, single-supply convenience, integrated shutdown, and proven performance in battery-operated sensor nodes - making it optimal for volume industrial and portable medical designs where 2MHz bandwidth and 415µA IQ meet system requirements.
Availability
INA331AIDGKRG4 is available at Aetrix Electronics and suitable for industrial sensor amplifiers, portable medical devices, and field utility meters requiring stable component supply and long-term manufacturability.
Supply support for INA331AIDGKRG4 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 decades of expertise in precision amplifiers and signal-chain solutions.
The INA331 family was designed specifically for low-cost, low-power instrumentation tasks in single-supply systems - targeting bridge, RTD, and thermocouple sensor interfaces where accuracy, size, and power efficiency are critical.
FAQ
What is the maximum gain achievable with INA331AIDGKRG4?
The INA331AIDGKRG4 supports externally programmable gain from 5V/V to 1000V/V using the equation G = 5 + (5R₂/R₁). At G = 1000, bandwidth reduces to ~10kHz, and stability requires careful layout and optional feedback capacitance per Figure 8 in the datasheet. Gain accuracy remains dominated by external resistor tolerance and temperature coefficient.
Does INA331AIDGKRG4 require external decoupling capacitors?
Yes - the INA331AIDGKRG4 requires 0.1µF ceramic capacitors placed as close as possible to both V+ (Pin 6) and V– (Pin 4) pins. This is mandatory for stable operation, especially in noisy environments or with high-impedance power sources, as specified in the Applications Information section of the SBOS215C datasheet.
Can INA331AIDGKRG4 drive ADC inputs directly?
Yes - the INA331AIDGKRG4's rail-to-rail output and 2.0MHz bandwidth allow direct connection to SAR and sigma-delta ADCs with input capacitance ≤100pF (e.g., ADS7818). For heavier capacitive loads (>100pF), a buffer such as OPA340 is recommended to prevent settling-time degradation and overshoot.
What is the common-mode input voltage range for INA331AIDGKRG4 at 3.3V supply?
At VS = 3.3V, the INA331AIDGKRG4 common-mode input range is approximately 0.4V to 2.5V (interpolated from datasheet specs at 2.7V and 5.0V). The upper limit is constrained by the second-stage amplifier's headroom (V+ – 1.2V), and the lower limit depends on REF voltage per VOA1 = 5/4·VCM – 1/4·VREF.
Is INA331AIDGKRG4 RoHS compliant and lead-free?
Yes - the INA331AIDGKRG4 is RoHS compliant and features lead-free (NIPDAU) termination, as confirmed in TI's Package Option Addendum (15-Jul-2026). It meets JEDEC MSL Level-2-260C-1 YEAR moisture sensitivity requirements and is qualified for reflow soldering at peak temperatures up to 260°C.
INA331AIDGKRG4 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
INA331AIDGKRG4 FAQ
1.How can I place an order for INA331AIDGKRG4 through Aetrix?
Please submit a Request for Quotation (RFQ) for INA331AIDGKRG4 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 INA331AIDGKRG4 reliable?
The price and inventory of INA331AIDGKRG4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for INA331AIDGKRG4 is usually 5 days.
3.What payment methods are accepted for INA331AIDGKRG4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for INA331AIDGKRG4 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for INA331AIDGKRG4?
INA331AIDGKRG4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your INA331AIDGKRG4 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 INA331AIDGKRG4?
For technical support, including INA331AIDGKRG4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your INA331AIDGKRG4 requirements.
6.How does Aetrix verify that INA331AIDGKRG4 is sourced from the original manufacturer or authorized distributors?
All INA331AIDGKRG4 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 INA331AIDGKRG4 meets industry standards.
7.What is the process for return or replacement of INA331AIDGKRG4?
All INA331AIDGKRG4 units undergo pre-shipment inspection (PSI). If there is an issue with INA331AIDGKRG4, 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 INA331AIDGKRG4 part is unused and in its original packaging.
Return procedure for INA331AIDGKRG4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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