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Texas Instruments INA128U/2K5
- Part No.:
- INA128U/2K5
- Manufacturer:
- Texas Instruments
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
INA128U/2K5.pdf
- Description:
- IC INST AMP 1 CIRCUIT 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,284
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Product details
Overview
INA128U/2K5 from Texas Instruments is a precision, low-power instrumentation amplifier designed for high-accuracy differential signal conditioning in noisy industrial and medical environments. It delivers 50 μV maximum offset voltage, 0.5 μV/°C maximum drift, 1.3 MHz bandwidth at G = 1, 120 dB minimum CMRR, and ±40 V input overvoltage protection - enabling reliable front-end amplification in pressure transmitters and ECG systems.
For engineers reviewing the INA128U/2K5 datasheet, INA128U/2K5 pinout, INA128U/2K5 application, or INA128U/2K5 equivalent, key selection criteria include gain-setting resistor dependency (G = 1 + 50 kΩ/RG), SOIC-8 package thermal performance (RθJA = 110 °C/W), dual-supply operation (±2.25 V to ±18 V), and chip-site-origin–dependent bias current (≤5 nA for CSO: SHE).
Technical Context
The INA128U/2K5 implements a three-op-amp architecture with current-feedback input stages, enabling 200 kHz bandwidth even at G = 100. Its laser-trimmed thin-film resistors ensure stable gain accuracy and low drift across temperature.
Input overvoltage protection circuitry clamps ±40 V faults without damage, while the REF pin allows output level shifting relative to ground or system reference - critical for single-supply DAQ interfacing and isolated sensor signal chains.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Offset voltage | 50 μV max (RTI) - ensures ≤0.5 mV error at G = 100 before calibration |
| CMRR | 120 dB min at G = 100 - rejects >1 V common-mode interference as <1 μV error |
| Bandwidth | 1.3 MHz at G = 1 - supports ≥650 kHz sine-wave acquisition without −3 dB attenuation |
| Supply range | ±2.25 V to ±18 V - operates from low-voltage battery rails up to industrial ±15 V systems |
| Quiescent current | 700 μA max - enables <1.5 mW total power at ±5 V, suitable for portable instrumentation |
| Input protection | ±40 V fault tolerance - eliminates need for external series resistors or TVS diodes |
| Gain equation | G = 1 + 50 kΩ/RG - sets precise gain from 1 to 10,000 using one external resistor |
Pinout & Package
INA128U/2K5 is supplied in an 8-pin SOIC (D) package measuring 4.9 mm × 6 mm, optimized for surface-mount assembly and thermal dissipation (RθJA = 110 °C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 8 | RG (gain-set) | Connect external resistor between pins 1 and 8 to set gain per G = 1 + 50 kΩ/RG |
| 2 | VIN− | Inverting input - accepts differential signal with 10 GΩ || 2 pF common-mode impedance |
| 3 | VIN+ | Non-inverting input - matched to VIN− for optimal CMRR and bias current cancellation |
| 4 | V− | Negative supply rail - must be decoupled locally; supports −2.25 V to −18 V operation |
| 5 | REF | Output reference - defines output DC level; requires low-impedance connection to avoid CMRR degradation |
| 6 | VO | Amplified output - swings to within 1.4 V of rails (CSO: SHE); drives 10 kΩ loads |
| 7 | V+ | Positive supply rail - must be decoupled locally; supports +2.25 V to +18 V operation |
Key Features
| Feature | Design Value |
|---|---|
| Laser-trimmed gain resistors | Ensures ≤0.024% gain error at G = 1 and ≤0.5% at G = 1000 without external calibration |
| Overvoltage-protected inputs | Withstands ±40 V continuous input faults - removes need for discrete protection components |
| Low 1/f noise | 0.2 μVPP (0.1–10 Hz) - enables stable microvolt-level DC measurements in weigh scales |
| Wide common-mode range | Operates with inputs from (V−) + 2 V to (V+) − 2 V - accommodates sensor outputs near supply rails |
| Chip-site-origin specification | CSO: SHE variant guarantees ≤5 nA input bias current - critical for high-impedance pH or thermocouple sensors |
Applications
| Pressure Transmitter | Electrocardiogram (ECG) |
|---|---|
Use Scenario: Amplifies mV-level bridge output from strain-gauge-based pressure sensors in industrial process control. IC Role / Device Role / Timing Role: Precision instrumentation amplifier providing fixed-gain (G = 100–500) differential-to-single-ended conversion with rail-to-rail compatible output swing. Use Value: 120 dB CMRR rejects 4–20 mA loop noise; ±40 V input protection survives field wiring faults; 50 μV offset enables <0.1% FS accuracy. |
Use Scenario: Front-end amplification of µV-level differential cardiac signals in portable or bedside ECG monitors. IC Role / Device Role / Timing Role: Low-noise, high-CMRR IA configured for G = 1000 with driven-right-leg (DRL) feedback via REF pin. Use Value: 0.2 μVPP 0.1–10 Hz noise preserves QRS morphology; input protection guards against defibrillation pulses; 700 μA IQ extends battery life. |
| Temperature Transmitter | Analog Input Module |
Use Scenario: Conditioned output from RTD or thermocouple sensors in HVAC or factory automation transmitters. IC Role / Device Role / Timing Role: Programmable-gain IA referenced to 4–20 mA loop ground, with REF pin tied to loop return. Use Value: 0.5 μV/°C drift limits temperature error to <0.05°C over −40°C to +85°C; wide supply range supports 12–24 V loop power. |
Use Scenario: Universal analog input channel in PLC or data acquisition systems accepting ±10 V, 0–20 mA, or thermocouple inputs. IC Role / Device Role / Timing Role: Reconfigurable gain stage (G = 1–1000) with REF pin used for level-shifting into ADC input range. Use Value: Single-resistor gain setting simplifies channel calibration; 1.3 MHz bandwidth supports 100 kSPS sampling; SOIC-8 footprint eases layout reuse. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar instrumentation amplifier applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| INA129U/2K5 | Uses G = 1 + 49.4 kΩ/RG; lower gain drift (±5 ppm/°C vs ±10 ppm/°C); identical pinout and specs otherwise | Preferred where drop-in replacement of legacy 49.4 kΩ-based designs is required | Select INA129U/2K5 only when matching existing gain-resistor networks or upgrading from older INA129 variants |
| INA828IDR | Lower input bias current (0.6 nA max vs 5 nA), lower noise (7 nV/√Hz vs 8 nV/√Hz), same quiescent current and package | Better suited for ultra-high-impedance sources (e.g., glass pH electrodes) and low-noise DAQ | Choose INA828IDR when bias current or broadband noise dominates system error budget - not a pin-compatible substitute |
Compared with INA129U/2K5, the INA128U/2K5 provides industry-standard gain scaling but slightly higher gain drift; versus INA828IDR, it trades 1 nV/√Hz more noise and 4.4 nA higher bias current for proven long-term stability in cost-sensitive industrial transmitters.
Availability
INA128U/2K5 is available at Aetrix Electronics and suitable for pressure transmitter design, ECG front-end development, and analog input module production requiring stable component supply and full traceability.
Supply support for INA128U/2K5 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 delivering analog and embedded processing solutions for industrial, automotive, and communications markets.
The INA12x family was engineered for precision sensor signal conditioning in harsh environments - emphasizing low drift, robust input protection, and flexible gain configuration without sacrificing power efficiency.
FAQ
What is the maximum gain achievable with INA128U/2K5?
The INA128U/2K5 supports gains from 1 to 10,000 using a single external resistor per the equation G = 1 + 50 kΩ/RG. At G = 10,000, RG = 5 Ω (±1% tolerance recommended). Bandwidth reduces to 20 kHz (CSO: SHE) or 33 kHz (CSO: FRE), and gain error increases to ±1% max. The INA128U/2K5 maintains functionality across this full range under specified operating conditions.
Does INA128U/2K5 require external capacitors for stability?
No external compensation capacitors are required for stability with the INA128U/2K5. It is internally compensated for unity-gain stability and remains stable driving capacitive loads up to 1000 pF. For loads >100 pF, TI recommends adding a 10 Ω series resistor between VO and the load to maintain phase margin - a practice verified in the INA128U/2K5 datasheet Figure 8-1 and Section 8.5.
How does the REF pin function in INA128U/2K5 circuits?
The REF pin on the INA128U/2K5 sets the output DC level: VO = G × (VIN+ − VIN−) + VREF. It must be driven by a low-impedance source (<8 Ω) to preserve CMRR. Grounding REF yields ground-referenced output; connecting to a DAC or bias voltage enables level-shifting - essential for interfacing with unipolar ADCs. This behavior is intrinsic to the INA128U/2K5's three-op-amp topology.
Is INA128U/2K5 suitable for single-supply operation?
Yes, the INA128U/2K5 operates from a single 4.5 V to 36 V supply (e.g., +5 V or +24 V with V− = GND). Input common-mode range extends from (V−) + 2 V to (V+) − 2 V, and output swings to within 1.4 V of each rail (CSO: SHE). For true rail-to-rail input/output, external level-shifting or a different amplifier family is required - the INA128U/2K5 does not support VIN = V− or VIN = V+.
What is the impact of chip site origin (CSO) on INA128U/2K5 performance?
The INA128U/2K5 is qualified across multiple fabrication flows, labeled CSO: SHE or CSO: FRE. CSO: SHE guarantees ≤5 nA input bias current and 1.3 MHz bandwidth; CSO: FRE offers lower bias current (≤0.6 nA) but reduced bandwidth (33 kHz at G = 1000) and higher output swing capability (to within 0.15 V of rails). System design must account for CSO-specific parameters - the INA128U/2K5 part number itself does not encode CSO, so datasheet tables must be consulted per lot.
INA128U/2K5 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Amplifier Type:
- Instrumentation
- Number of Circuits:
- 1
- Output Type:
- -
- Slew Rate:
- 4V/µs
- Gain Bandwidth Product:
- -
- -3db Bandwidth:
- 1.3 MHz
- Current - Input Bias:
- 2 nA
- Voltage - Input Offset:
- 10 µV
- Current - Supply:
- 700µA
- Current - Output / Channel:
- 15 mA
- Voltage - Supply Span (Min):
- 4.5 V
- Voltage - Supply Span (Max):
- 36 V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
INA128U/2K5 FAQ
1.How can I place an order for INA128U/2K5 through Aetrix?
Please submit a Request for Quotation (RFQ) for INA128U/2K5 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 INA128U/2K5 reliable?
The price and inventory of INA128U/2K5 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for INA128U/2K5 is usually 5 days.
3.What payment methods are accepted for INA128U/2K5?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for INA128U/2K5 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for INA128U/2K5?
INA128U/2K5 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your INA128U/2K5 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 INA128U/2K5?
For technical support, including INA128U/2K5 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your INA128U/2K5 requirements.
6.How does Aetrix verify that INA128U/2K5 is sourced from the original manufacturer or authorized distributors?
All INA128U/2K5 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 INA128U/2K5 meets industry standards.
7.What is the process for return or replacement of INA128U/2K5?
All INA128U/2K5 units undergo pre-shipment inspection (PSI). If there is an issue with INA128U/2K5, 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 INA128U/2K5 part is unused and in its original packaging.
Return procedure for INA128U/2K5:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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