My Inquiry
My Account
Texas Instruments INA321EA/2K5G4
- Part No.:
- INA321EA/2K5G4
- Manufacturer:
- Texas Instruments
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
INA321EA/2K5G4.pdf
- Description:
- IC INST AMP 1 CIRCUIT 8VSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,621
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
INA321EA/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 ECG front-ends and bridge sensor signal conditioning where low quiescent current (40 µA/channel) and −55°C to +125°C operation are critical.
For engineers reviewing the INA321EA/2K5G4 datasheet, INA321EA/2K5G4 pinout, INA321EA/2K5G4 application, or INA321EA/2K5G4 equivalent, key selection criteria include micropower shutdown (<1 µA), rail-to-rail output swing (V⁺ − 0.02 V), high-precision gain accuracy (±0.02% at G=5), input bias current (10 pA), and compatibility with single-supply (2.7–5.5 V) industrial and medical sensing systems.
Technical Context
The INA321EA/2K5G4 implements a three-op-amp instrumentation architecture with internal gain-setting resistors for nominal G = 5, extended via external R₁/R₂ to 5–1000 V/V. Its CMOS input stage delivers 10¹³ Ω input impedance and 10 pA bias current, enabling direct interfacing with high-impedance sensors like thermistors and RTDs without loading error.
It features a dedicated shutdown pin that reduces quiescent current to <1 µA within nanoseconds while placing the output in high-impedance state - ideal for time-multiplexed sensor arrays. The REF pin defines output zero level and enables offset trimming, but requires low-impedance drive to maintain >90 dB CMRR up to 3 kHz.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Gain Accuracy | ±0.02% at G = 5 - ensures sub-0.1 mV error in 5 V full-scale bridge outputs at room temperature |
| Input Offset Voltage | ±200 µV max - enables resolution of <10 µV differential signals after gain, critical for ECG baseline stability |
| CMRR | 94 dB at DC, ≥77 dB over −55°C to +125°C - rejects 50/60 Hz line noise in industrial field meters and physiological amplifiers |
| Bandwidth | 500 kHz at G = 5 - supports fast transient capture in A/D converter signal conditioning up to 100 kSPS |
| Quiescent Current | 40 µA per channel - allows battery-powered operation for >1 year on a CR2032 in intermittent-sampling sensor nodes |
| Rail-to-Rail Output | VOUT swings to (V+) − 20 mV - eliminates need for level-shifting when driving 2.5 V reference ADCs from 3.3 V supply |
| Operating Temp | −55°C to +125°C - qualified for under-hood automotive instrumentation and downhole oilfield sensor modules |
Pinout & Package
INA321EA/2K5G4 is packaged in MSOP-8 (DGK) with exposed thermal pad, footprint compatible with industry-standard 3 mm × 3 mm space-constrained PCB layouts.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (RG) | Gain Resistor Terminal | Connects to external R₂ to set gain per G = 5 + 5·R₂/R₁; open for G = 5, shorted to VOUT for unity-gain buffer mode |
| 2 (VIN−) | Inverting Input | Differential input node; requires matched bias return path (e.g., dual 1 MΩ to REF) to prevent CM saturation |
| 3 (VIN+) | Non-inverting Input | Differential input node; high-impedance (10¹³ Ω) CMOS input accepts microvolt-level bridge outputs directly |
| 4 (V−) | Negative Supply | Ground or negative rail; must be decoupled with 0.1 µF ceramic capacitor placed ≤2 mm from pin |
| 5 (Shutdown) | Enable Control | Pull <0.8 V (at 5 V supply) to enter <1 µA shutdown; rise time <1 µs enables rapid multiplexing between sensor channels |
| 6 (V+) | Positive Supply | 2.7–5.5 V single supply; internal ESD diodes clamp inputs to rails ±0.5 V - external current limiting required beyond that range |
| 7 (VOUT) | Amplified Output | Rail-to-rail output referenced to REF; drives ≥10 kΩ loads directly; buffers needed for <600 Ω or capacitive ADC inputs |
| 8 (REF) | Output Reference | Defines zero-output level; must be driven low-impedance (≤160 Ω) to preserve CMRR; used for offset trimming via external op-amp |
Key Features
| Feature | Design Value |
|---|---|
| Micropower Shutdown | Draws <1 µA during sleep, enabling battery life extension in portable ECG monitors and wireless sensor nodes |
| Laser-Trimmed Gain Accuracy | ±0.02% at G = 5 minimizes calibration overhead in factory-trimmed field utility meters |
| High CMRR Over Frequency | Maintains >75 dB CMRR up to 3 kHz - suppresses harmonics in motor-driven industrial equipment |
| Single-Supply Flexibility | Operates from 2.7 V to 5.5 V with rail-to-rail output - eliminates dual-supply complexity in PCMCIA cards and IoT edge nodes |
| Low Input Bias Current | 10 pA maximum avoids voltage drop across high-Z sources (e.g., pH electrodes, piezoresistive sensors) |
Applications
| Industrial Sensor Amplifiers | Physiological Amplifiers |
|---|---|
Use Scenario: Amplifying mV-level differential output from a 350 Ω strain gauge in a load cell under vibration and temperature cycling. IC Role / Device Role / Timing Role: Precision instrumentation amplifier providing fixed G = 5 gain, rejecting common-mode noise from 4–20 mA loop coupling and 50 Hz mains interference. Use Value: 94 dB CMRR and ±200 µV offset enable <0.1% full-scale error across −40°C to +85°C without recalibration. | Use Scenario: Front-end amplification of 1–2 mV ECG signals from limb electrodes in wearable fitness trackers. IC Role / Device Role / Timing Role: Low-noise, micropower IA with shutdown control for duty-cycled acquisition to extend coin-cell battery life. Use Value: 40 µA quiescent current and <1 µA shutdown allow >12-month operation on CR2032; 10 pA bias prevents electrode polarization drift. |
| A/D Converter Signal Conditioning | Differential Line Receivers with Gain |
Use Scenario: Driving ADS7818 12-bit SAR ADC input with 500 kHz bandwidth requirement in portable data loggers. IC Role / Device Role / Timing Role: Signal conditioner delivering rail-to-rail output swing (V⁺ − 20 mV) into capacitive CDAC input without external buffer. Use Value: 500 kHz bandwidth and 0.4 V/µs slew rate ensure <0.1% settling in <8 µs for 2 V step - matching ADC sampling clock timing budgets. | Use Scenario: Receiving balanced analog signals from 100 Ω twisted-pair lines in building automation controllers. IC Role / Device Role / Timing Role: Differential receiver with programmable gain (G = 5–100) rejecting ground-loop noise and RF ingress. Use Value: 110 dB crosstalk (dual version) and 94 dB CMRR suppress inter-channel interference in multi-zone HVAC monitoring. |
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 quiescent current (17 µA), lower offset (±25 µV), but narrower temp range (−40°C to +125°C); same MSOP-8 package | Better suited for ultra-low-power wearable biosensors, less suitable for extended-temperature automotive or aerospace use | Select INA333AIDGKR only if operating temperature stays above −40°C and sub-25 µV offset is mandatory |
| AD8221ARMZ | Higher bandwidth (825 kHz), higher PSRR (120 dB), but higher IQ (350 µA) and no shutdown; 8-lead SOIC package | Preferred for high-speed test equipment requiring fast settling, not for battery-powered or space-constrained designs | Choose AD8221ARMZ when bandwidth >800 kHz and power budget >300 µA/channel is acceptable |
Compared with INA333AIDGKR and AD8221ARMZ, the INA321EA/2K5G4 uniquely balances extended temperature operation (−55°C to +125°C), micropower shutdown (<1 µA), and MSOP-8 footprint - making it optimal for ruggedized industrial sensors and automotive body electronics where reliability and board area are constrained.
Availability
INA321EA/2K5G4 is available at Aetrix Electronics and suitable for industrial sensor amplifiers, physiological monitoring systems, A/D converter signal conditioning, and differential line receivers requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for INA321EA/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 amplifiers and signal chain solutions.
The INA321 family was designed specifically for low-power, high-accuracy instrumentation in harsh environments - targeting bridge-based industrial sensors, medical diagnostics, and field utility metering where micropower, rail-to-rail output, and wide temperature range are non-negotiable.
FAQ
What is the gain configuration of INA321EA/2K5G4 and how is it set?
The INA321EA/2K5G4 is internally configured for G = 5, but supports user-programmable gains from 5 V/V to 1000 V/V using external resistors R₁ and R₂ per the equation G = 5 + 5·(R₂/R₁). Pin 1 (RG) connects to R₂; R₁ bridges RG and REF. No external resistors yield G = 5. This flexibility allows precise gain tailoring without changing the INA321EA/2K5G4 itself.
Does INA321EA/2K5G4 support true rail-to-rail output swing?
Yes, the INA321EA/2K5G4 delivers rail-to-rail output swing - specifically, VOUT reaches within 20 mV of V+ and V− rails when gain ≥10 and load ≥25 kΩ. At G = 5, output swing is limited to (V+) − 50 mV. This behavior is confirmed in Electrical Characteristics tables and Typical Characteristics curves for Output Voltage Swing vs Load Resistance.
What is the purpose of the REF pin on INA321EA/2K5G4 and how should it be driven?
The REF pin on INA321EA/2K5G4 sets the output's zero-reference level and enables offset trimming. It must be driven with low impedance (≤160 Ω) to preserve CMRR; exceeding this resistance degrades CMRR to ≤80 dB. A buffered voltage (e.g., from OPA336) or precision DAC output is recommended. Direct connection to mid-supply via resistive divider is acceptable only if source impedance is minimized.
Can INA321EA/2K5G4 operate from a single 3.3 V supply?
Yes, the INA321EA/2K5G4 is fully specified for single-supply operation from 2.7 V to 5.5 V. At 3.3 V, it maintains 40 µA quiescent current, ±200 µV offset, 94 dB CMRR, and 500 kHz bandwidth. Input common-mode range extends from 0.55 V to 3.8 V (at VS = 5 V) - scaled proportionally at 3.3 V - and REF must remain ≥1.2 V below V+ for proper A2 amplifier operation.
How does the shutdown feature of INA321EA/2K5G4 behave during system sleep cycles?
The shutdown pin on INA321EA/2K5G4 pulls the amplifier into sub-1 µA quiescent state within nanoseconds when driven below 0.8 V (at 5 V supply); recovery to full operation takes <1 µs. During shutdown, the output enters high-impedance state - enabling safe multiplexing of multiple INA321EA/2K5G4 channels onto shared ADC inputs without cross-talk or loading.
INA321EA/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
INA321EA/2K5G4 FAQ
1.How can I place an order for INA321EA/2K5G4 through Aetrix?
Please submit a Request for Quotation (RFQ) for INA321EA/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 INA321EA/2K5G4 reliable?
The price and inventory of INA321EA/2K5G4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for INA321EA/2K5G4 is usually 5 days.
3.What payment methods are accepted for INA321EA/2K5G4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for INA321EA/2K5G4 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for INA321EA/2K5G4?
INA321EA/2K5G4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your INA321EA/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 INA321EA/2K5G4?
For technical support, including INA321EA/2K5G4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your INA321EA/2K5G4 requirements.
6.How does Aetrix verify that INA321EA/2K5G4 is sourced from the original manufacturer or authorized distributors?
All INA321EA/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 INA321EA/2K5G4 meets industry standards.
7.What is the process for return or replacement of INA321EA/2K5G4?
All INA321EA/2K5G4 units undergo pre-shipment inspection (PSI). If there is an issue with INA321EA/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 INA321EA/2K5G4 part is unused and in its original packaging.
Return procedure for INA321EA/2K5G4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
INA321EA/2K5G4 Tags
-
LM358DT
STMicroelectronics
-
LM358DR
Texas Instruments
-
LM2904DR
Texas Instruments
-
LM358ADR
Texas Instruments
-
LM2904DGKR
Texas Instruments
-
LM324DR
Texas Instruments
-
MCP6006T-E/OT
Microchip Technology
-
MCP6006UT-E/OT
Microchip Technology
-
LM324PWR
Texas Instruments
-
LM2902PWR
Texas Instruments
-
LM2902DR
Texas Instruments
-
LM358P
Texas Instruments
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
