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Texas Instruments INA321E/2K5G4
- Part No.:
- INA321E/2K5G4
- Manufacturer:
- Texas Instruments
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
INA321E/2K5G4.pdf
- Description:
- IC INST AMP 1 CIRCUIT 8VSSOP
- Quantity:
- Payment:
- Shipping:
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Product details
Overview
INA321E/2K5G4 from Texas Instruments is a rail-to-rail output, micropower CMOS instrumentation amplifier in MSOP-8 package, configured for fixed 5V/V gain with external resistor programmability (G = 5 + 5·R₂/R₁), ±200 µV offset voltage, 94 dB CMRR at DC, and 500 kHz bandwidth - deployed in bridge sensor signal conditioning for industrial metering and ECG front-ends.
For engineers reviewing the INA321E/2K5G4 datasheet, INA321E/2K5G4 pinout, INA321E/2K5G4 application, or INA321E/2K5G4 equivalent, this page delivers verified specifications, validated dual-channel alternatives, real-world use-value per application, and supply-chain support for low-power precision analog designs requiring −55°C to +125°C operation and <1 µA shutdown current.
Technical Context
The INA321E/2K5G4 implements a modified three-op-amp architecture with internal gain stage (G = 5) and external RG-based scaling, enabling user-programmable gains from 5 V/V to 1000 V/V while maintaining 0.02% gain accuracy and ±2 ppm/°C drift. Its CMOS input stage delivers 10 pA bias current and 10¹³ Ω || 3 pF input impedance.
It operates from single +2.7 V to +5.5 V supplies, supports rail-to-rail output swing (to within 20 mV of V+ at G ≥ 10), and features a dedicated shutdown pin that reduces quiescent current to <1 µA with microsecond wake-up - critical for battery-powered multiplexed sensor systems.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Gain Accuracy | ±0.02% at G = 5 - enables high-fidelity differential amplification without post-calibration in precision bridge measurements. |
| Input Offset Voltage | ±200 µV max - ensures sub-millivolt error floor in RTD or thermistor interfaces with 16-bit ADCs. |
| CMRR | 94 dB at DC, >77 dB up to 3 kHz - rejects line-frequency noise and common-mode interference in ECG/EMG front-ends. |
| Bandwidth | 500 kHz at G = 5 - supports fast settling (<8 µs to 0.1%) for driving SAR ADCs like ADS7818 at ≤100 kHz sampling rates. |
| Quiescent Current | 40 µA per channel - allows continuous operation for >1 year on a CR2032 coin cell in portable diagnostic devices. |
| Shutdown Current | <1 µA - enables true low-power sleep mode during sensor channel multiplexing without PCB-level power gating. |
| Operating Temp Range | −55°C to +125°C - qualified for under-hood automotive instrumentation and industrial field utility meters. |
Pinout & Package
INA321E/2K5G4 is packaged in MSOP-8 (DGK) with exposed thermal pad, footprint-compatible with industry-standard 3 mm × 3 mm space-constrained layouts.
| Pin | Circuit Role | Design Meaning |
|---|---|---|
| 1 (RG) | External Gain Resistor Terminal | Connects to R₂ in G = 5 + 5·R₂/R₁ network; sets programmable gain above 5 V/V with matched TC resistors. |
| 2 (VIN−) | Inverting Input | Differential input node; requires matched bias return path (e.g., dual 47 kΩ to REF) for optimal CMRR and offset stability. |
| 3 (VIN+) | Non-inverting Input | Differential input node; high-impedance (10¹³ Ω) CMOS input enables direct connection to high-Z sensors like piezoresistive bridges. |
| 4 (V−) | Negative Supply Rail | Ground reference for single-supply operation; must be decoupled with 0.1 µF capacitor near pin. |
| 5 (Shutdown) | Active-Low Sleep Control | Pulled high to V+ for normal operation; driven <0.8 V (at 5 V supply) to enter <1 µA shutdown with microsecond wake-up. |
| 6 (V+) | Positive Supply Rail | +2.7 V to +5.5 V operation; absolute max 7.5 V; requires local 0.1 µF ceramic decoupling. |
| 7 (VOUT) | Amplified Output | Rail-to-rail output (to within 20 mV of V+) at G ≥ 10; drives 25 kΩ loads directly or 600 Ω via OPA340 buffer. |
| 8 (REF) | Output Reference Level | Defines zero-output voltage; must be low-impedance (≤160 Ω series) to preserve 94 dB CMRR; used for offset trimming. |
Key Features
| Feature | Design Value |
|---|---|
| Micropower Operation | 40 µA/channel quiescent current enables multi-year battery life in portable physiological monitors and wireless sensor nodes. |
| User-Programmable Gain | G = 5 + 5·R₂/R₁ equation supports precise, temperature-stable gain scaling from 5× to 1000× using external matched resistors. |
| Rail-to-Rail Output | Swings to within 20 mV of V+ at G ≥ 10, maximizing dynamic range when interfacing with 3.3 V or 5 V SAR ADCs. |
| High CMRR Over Frequency | Maintains >77 dB CMRR up to 3 kHz - suppresses 50/60 Hz mains interference without external notch filters in medical ECG circuits. |
| Low Input Bias Current | 10 pA max enables accurate amplification of high-impedance sources (e.g., pH electrodes, thermopiles) without signal degradation. |
Applications
| Industrial Bridge Sensing | Medical ECG Front-End |
|---|---|
Use Scenario: Amplifying mV-level differential output from strain-gauge load cells or pressure transducers in smart utility meters. IC Role / Device Role / Timing Role: Precision instrumentation amplifier providing fixed 5× gain, rejecting common-mode noise from long sensor cables and switching power supplies. Use Value: Enables 16-bit resolution measurement with <0.1% total error across −40°C to +85°C ambient, eliminating discrete op-amp compensation networks. | Use Scenario: Low-noise, low-power amplification of differential heart signals from limb electrodes in portable fitness trackers. IC Role / Device Role / Timing Role: First-stage instrumentation amplifier with shutdown control synchronized to ECG sampling intervals to minimize average power. Use Value: Delivers 94 dB CMRR at 60 Hz and <1 µA shutdown current - extends battery life while meeting IEC 60601-2-51 ECG accuracy requirements. |
| A/D Converter Signal Conditioning | Field Utility Metering |
Use Scenario: Driving the capacitive input of SAR ADCs (e.g., ADS7818) in data acquisition modules with ≤100 kHz sample rates. IC Role / Device Role / Timing Role: High-speed, low-output-impedance buffer delivering fast-settling (8 µs to 0.1%), rail-to-rail signals to ADC inputs. Use Value: Eliminates need for external op-amp buffer stages, reducing BOM count and layout area while preserving SNR in 12-bit systems. | Use Scenario: Signal conditioning for shunt-based current sensing in smart electricity meters operating in harsh outdoor environments. IC Role / Device Role / Timing Role: Precision gain stage converting µV-level shunt voltage to full-scale ADC input, with guaranteed operation from −55°C to +125°C. Use Value: Meets ANSI C12.20 Class 0.2 accuracy over full temperature range without calibration drift compensation firmware. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar instrumentation amplifier applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| INA322E/2K5 | Same MSOP-8 package, but G = 10 (not 5); 0.05% gain error; 350 kHz bandwidth at G = 10. | Better suited for higher-gain, lower-bandwidth applications where 10× fixed gain suffices and 500 kHz is unnecessary. | Select INA322E/2K5 only if system design requires exactly 10× gain and can accept reduced bandwidth and looser gain accuracy. |
| INA333AIDGKR | Zerø-drift architecture; 25 µV max offset; 500 kHz BW at G = 1; 50 µA IQ; TSSOP-8 package. | Superior DC precision for ultra-low-offset applications (e.g., thermocouple amplification), but lacks shutdown and has different pinout. | Choose INA333AIDGKR when offset drift dominates error budget and shutdown functionality is not required. |
Compared with INA322E/2K5 and INA333AIDGKR, the INA321E/2K5G4 uniquely balances 5× fixed gain, 500 kHz bandwidth, <1 µA shutdown, and −55°C to +125°C qualification - making it optimal for cost-sensitive, battery-operated industrial and medical sensor nodes where moderate DC precision and fast settling are jointly critical.
Availability
INA321E/2K5G4 is available at Aetrix Electronics and suitable for industrial sensor amplifiers, physiological monitoring systems, A/D converter signal conditioning, and field utility metering requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for INA321E/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 leader specializing in analog and embedded processing technologies, with decades of expertise in precision signal chain solutions.
The INA321 family was designed specifically for low-power, high-accuracy instrumentation in space-constrained, battery-operated, and wide-temperature industrial and medical applications - emphasizing micropower consumption, rail-to-rail output, and robust CMRR performance.
FAQ
What is the exact gain configuration of the INA321E/2K5G4?
The INA321E/2K5G4 is internally configured for a fixed gain of 5 V/V, but supports user-programmable gains ≥5 V/V via external resistors using the equation G = 5 + 5·(R₂/R₁). This architecture retains the 0.02% gain accuracy and ±2 ppm/°C drift of the base 5× stage while enabling flexible system-level scaling without sacrificing precision.
Does the INA321E/2K5G4 support true rail-to-rail output swing?
Yes - the INA321E/2K5G4 achieves rail-to-rail output swing to within 20 mV of V+ when gain is ≥10 V/V and load is ≥25 kΩ. At G = 5, output swing is limited to (V+) − 0.02 V. This behavior is explicitly specified in the Electrical Characteristics table and confirmed in Typical Characteristics curves for Output Voltage Swing vs Load Resistance.
How does the shutdown feature of the INA321E/2K5G4 operate?
The INA321E/2K5G4 enters shutdown mode when its Shutdown pin is driven below 0.8 V (at 5 V supply), drawing <1 µA quiescent current. It wakes up in microseconds upon returning the pin to V+. This feature is validated across −55°C to +125°C and enables power cycling in multiplexed sensor arrays without external MOSFET switches or complex sequencing.
Can the INA321E/2K5G4 drive capacitive-input ADCs directly?
Yes - the INA321E/2K5G4 is optimized to drive capacitive-input SAR ADCs such as the ADS7818 (12-bit, ≤100 kHz sampling) without external buffering. Its low output impedance at high frequencies, fast settling time (8 µs to 0.1%), and rail-to-rail swing ensure minimal acquisition error and full utilization of ADC dynamic range.
What is the maximum common-mode input voltage range for the INA321E/2K5G4?
At V+ = 5 V, the INA321E/2K5G4 supports a common-mode input range of 0.55 V to 3.8 V. The upper limit is defined by the second-stage amplifier's input range (V+ − 1.2 V), and the lower limit depends on REF voltage per VOA1 = 5/4·VCM − 1/4·VREF. These limits are measured and guaranteed across −55°C to +125°C per the Electrical Characteristics table.
INA321E/2K5G4 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
INA321E/2K5G4 FAQ
1.How can I place an order for INA321E/2K5G4 through Aetrix?
Please submit a Request for Quotation (RFQ) for INA321E/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 INA321E/2K5G4 reliable?
The price and inventory of INA321E/2K5G4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for INA321E/2K5G4 is usually 5 days.
3.What payment methods are accepted for INA321E/2K5G4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for INA321E/2K5G4 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for INA321E/2K5G4?
INA321E/2K5G4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your INA321E/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 INA321E/2K5G4?
For technical support, including INA321E/2K5G4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your INA321E/2K5G4 requirements.
6.How does Aetrix verify that INA321E/2K5G4 is sourced from the original manufacturer or authorized distributors?
All INA321E/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 INA321E/2K5G4 meets industry standards.
7.What is the process for return or replacement of INA321E/2K5G4?
All INA321E/2K5G4 units undergo pre-shipment inspection (PSI). If there is an issue with INA321E/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 INA321E/2K5G4 part is unused and in its original packaging.
Return procedure for INA321E/2K5G4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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