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Texas Instruments INA321EA/250G4
- Part No.:
- INA321EA/250G4
- Manufacturer:
- Texas Instruments
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
INA321EA/250G4.pdf
- Description:
- IC INST AMP 1 CIRCUIT 8VSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,505
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Product details
Overview
INA321EA/250G4 from Texas Instruments is a micropower, rail-to-rail output CMOS instrumentation amplifier in MSOP-8 package, configured for fixed G = 5 gain with ±200 µV offset voltage, 94 dB CMRR at DC, and 500 kHz bandwidth. It operates from +2.7 V to +5.5 V single supply and supports industrial sensor signal conditioning across −55°C to +125°C.
For engineers reviewing the INA321EA/250G4 datasheet, INA321EA/250G4 pinout, INA321EA/250G4 application, or INA321EA/250G4 equivalent, key selection criteria include quiescent current (40 µA/channel), shutdown current (<1 µA), external gain resistor programmability, rail-to-rail output swing, and high-precision differential amplification for low-noise, battery-powered measurement systems.
Technical Context
The INA321EA/250G4 implements a three-op-amp instrumentation architecture with internal gain-setting resistors for G = 5, plus external RG pin support for user-programmable gains ≥5 via G = 5 + 5(R₂/R₁). Its CMOS input stage delivers 10 pA bias current and 10¹³ Ω || 3 pF input impedance, enabling direct interfacing with high-impedance sensors like RTDs and thermistors.
It features a dedicated shutdown pin that reduces quiescent current to <1 µA within nanoseconds, making it suitable for time-multiplexed sensor arrays and portable medical devices. The rail-to-rail output stage maintains ≤25 mV swing from rails at G ≥10 into 25 kΩ loads, while preserving 0.02% gain accuracy and 2 ppm/°C drift over temperature.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Gain Accuracy | ±0.02% at G = 5, ensuring minimal calibration burden in precision bridge amplifier designs |
| Input Offset Voltage | ±200 µV max at +25°C, enabling sub-millivolt-level differential signal resolution |
| CMRR | 94 dB at DC, rejecting line-frequency interference in industrial sensor front-ends |
| Bandwidth | 500 kHz at G = 5, supporting fast-sampling A/D converter interfaces up to 100 kSPS |
| Quiescent Current | 40 µA per channel, allowing multi-channel operation on coin-cell or energy-harvesting supplies |
| Operating Temp Range | −55°C to +125°C, qualified for under-hood automotive and downhole industrial environments |
| Rail-to-Rail Output | Swings to (V+) − 0.02 V, maximizing dynamic range when driving SAR ADCs with 0–VDD reference |
Pinout & Package
INA321EA/250G4 is packaged in MSOP-8 (DGK) with exposed thermal pad, rated for 150°C/W junction-to-ambient thermal resistance in surface-mount configuration.
| Pin | Circuit Role | Design Meaning |
|---|---|---|
| 1 (RG) | External Gain Resistor Terminal | Connects to R₂ in G = 5 + 5(R₂/R₁) network; open for G = 5, shorted to V− for minimum gain |
| 2 (VIN−) | Inverting Input | Differential input node; requires matched bias return path for optimal CMRR and offset performance |
| 3 (VIN+) | Non-inverting Input | Differential input node; high-impedance CMOS input enables direct connection to bridge sensors |
| 4 (V−) | Negative Supply Rail | Ground reference for single-supply operation; must be decoupled with 0.1 µF capacitor |
| 5 (Shutdown) | Active-Low Enable Control | Pull below 0.8 V (at V+ = 5 V) to enter <1 µA sleep mode; returns in microseconds |
| 6 (V+) | Positive Supply Rail | Accepts +2.7 V to +5.5 V; requires local 0.1 µF bypass capacitor for noise immunity |
| 7 (VOUT) | Amplified Output | Rail-to-rail output referenced to REF pin; drives 25 kΩ loads with <25 mV headroom at G ≥10 |
| 8 (REF) | Output Reference Level | Sets zero-output voltage; must be low-impedance (≤160 Ω) to preserve 94 dB CMRR |
Key Features
| Feature | Design Value |
|---|---|
| Micropower Operation | 40 µA/channel quiescent current enables >1-year battery life in wireless sensor nodes |
| Programmable Gain Architecture | G = 5 + 5(R₂/R₁) allows precise gain tuning from 5× to 1000× without degrading CMRR or noise |
| High-Precision DC Performance | ±200 µV offset and ±2 ppm/°C drift ensure stable baseline in long-duration physiological monitoring |
| Robust Input Protection | ESD diodes clamp inputs to rails ±0.5 V; supports 10 mA fault current with external limiting resistors |
| Wide Common-Mode Range | 0.35 V to 1.5 V at VS = 2.7 V enables operation with low-voltage sensor excitation sources |
Applications
| Industrial Sensor Amplifiers | Physiological Signal Acquisition |
|---|---|
|
Use Scenario: Amplifying mV-level differential outputs from strain-gauge load cells in factory-floor weighing systems. IC Role / Device Role / Timing Role: Precision instrumentation amplifier providing 5× fixed gain, rail-to-rail output, and 94 dB CMRR to reject 50/60 Hz power-line noise. Use Value: Enables direct interface to 16-bit SAR ADCs without additional level-shifting or filtering stages, reducing BOM count and PCB area. |
Use Scenario: Front-end amplification of ECG signals from limb electrodes in portable cardiac monitors. IC Role / Device Role / Timing Role: Low-bias-current (10 pA), low-noise instrumentation amplifier with shutdown control for multiplexed lead selection. Use Value: Delivers <200 µV offset and <1 µA shutdown current, extending battery runtime while maintaining diagnostic-grade signal fidelity. |
| A/D Converter Signal Conditioning | Differential Line Receivers with Gain |
|
Use Scenario: Driving ADS7818 12-bit capacitive-input ADC in low-power data acquisition modules. IC Role / Device Role / Timing Role: Rail-to-rail output buffer with 500 kHz bandwidth and 0.4 V/µs slew rate, optimized for CDAC input settling. Use Value: Eliminates need for external op-amp buffer, reducing power consumption by 40 µA and layout complexity in space-constrained IoT edge nodes. |
Use Scenario: Receiving and amplifying differential analog signals from isolated fieldbus transceivers in PLC I/O modules. IC Role / Device Role / Timing Role: High-CMRR (94 dB) differential receiver with programmable gain, rejecting common-mode transients on noisy factory floors. Use Value: Maintains signal integrity across 0–100 kHz bandwidth while operating from 3.3 V supply, simplifying power domain isolation design. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar instrumentation amplifier applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| INA322EA/250G4 | Higher bandwidth (1.5 MHz at G = 5), higher quiescent current (100 µA), same MSOP-8 package | Better suited for higher-speed data acquisition where speed outweighs power budget constraints | Select when system requires >1 MHz small-signal bandwidth and can accommodate +60 µA/channel extra current |
| INA333AIDRGT | Zerø-drift architecture, 25 µV max offset, 500 kHz BW, 50 µA IQ, same gain equation and pinout | Superior DC stability for long-duration measurements; no 1/f noise in ECG or precision weigh scales | Choose for applications demanding <1 µV/°C offset drift and ultra-low 0.1–10 Hz noise, accepting slightly higher cost |
Compared with INA322EA/250G4 and INA333AIDRGT, the INA321EA/250G4 offers the lowest quiescent current (40 µA) and best cost-performance balance for battery-powered industrial sensors, while retaining sufficient precision and bandwidth for most bridge and physiological front-ends without zerø-drift overhead.
Availability
INA321EA/250G4 is available at Aetrix Electronics and suitable for industrial sensor amplifiers, physiological signal acquisition, A/D converter signal conditioning, and differential line receivers requiring stable component supply across extended temperature ranges.
Supply support for INA321EA/250G4 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 signal chain solutions.
The INA321 family was designed for low-power, high-accuracy differential amplification in resource-constrained environments-targeting industrial sensing, medical instrumentation, and portable test equipment where micropower and rail-to-rail performance are critical.
FAQ
What is the maximum gain achievable with INA321EA/250G4?
The INA321EA/250G4 supports externally programmable gains from 5 V/V up to 1000 V/V using the equation G = 5 + 5(R₂/R₁). At G = 1000, bandwidth reduces to ~5 kHz, but the device maintains specified CMRR and offset performance across its full gain range. The internal 5× core ensures consistent accuracy regardless of external resistor tolerance.
Does INA321EA/250G4 require external decoupling capacitors?
Yes, the INA321EA/250G4 requires 0.1 µF 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 industrial environments or when driving capacitive loads. Failure to implement local decoupling may cause oscillation or degraded PSRR above 10 kHz.
Can INA321EA/250G4 operate from a 3.3 V supply?
Yes, the INA321EA/250G4 is fully specified from +2.7 V to +5.5 V. At 3.3 V, it delivers rail-to-rail output swing (to within 25 mV of rails at G ≥10), 40 µA quiescent current, and retains 90 dB CMRR across its −55°C to +125°C operating range. Input common-mode range adjusts to 0.35 V–1.5 V, compatible with typical 3.3 V sensor excitation schemes.
How does the shutdown feature affect output behavior in INA321EA/250G4?
When the Shutdown pin (Pin 5) is pulled below 0.8 V (at V+ = 5 V), the INA321EA/250G4 enters a high-impedance state drawing <1 µA total current. Its output goes to high-Z-not tri-stated to a defined voltage-making it ideal for multiplexed sensor arrays where channel isolation is required without loading downstream circuitry.
What is the recommended layout practice for the REF pin on INA321EA/250G4?
The REF pin (Pin 8) must be driven from a low-impedance source (<160 Ω) to maintain 94 dB CMRR. Use a dedicated op-amp buffer (e.g., OPA336) or low-ESR voltage divider with local 0.1 µF bypass. Avoid routing REF through long traces or shared PCB planes; any series resistance >160 Ω degrades CMRR to ≤80 dB, compromising noise rejection in sensitive applications.
INA321EA/250G4 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:
- 0.4V/µs
- Gain Bandwidth Product:
- -
- -3db Bandwidth:
- 500 kHz
- Current - Input Bias:
- 0.5 pA
- Voltage - Input Offset:
- 200 µV
- Current - Supply:
- 40µA
- Current - Output / Channel:
- 16 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
INA321EA/250G4 FAQ
1.How can I place an order for INA321EA/250G4 through Aetrix?
Please submit a Request for Quotation (RFQ) for INA321EA/250G4 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 INA321EA/250G4 reliable?
The price and inventory of INA321EA/250G4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for INA321EA/250G4 is usually 5 days.
3.What payment methods are accepted for INA321EA/250G4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for INA321EA/250G4 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for INA321EA/250G4?
INA321EA/250G4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your INA321EA/250G4 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 INA321EA/250G4?
For technical support, including INA321EA/250G4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your INA321EA/250G4 requirements.
6.How does Aetrix verify that INA321EA/250G4 is sourced from the original manufacturer or authorized distributors?
All INA321EA/250G4 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 INA321EA/250G4 meets industry standards.
7.What is the process for return or replacement of INA321EA/250G4?
All INA321EA/250G4 units undergo pre-shipment inspection (PSI). If there is an issue with INA321EA/250G4, 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 INA321EA/250G4 part is unused and in its original packaging.
Return procedure for INA321EA/250G4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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