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Texas Instruments INA155U/2K5G4
- Part No.:
- INA155U/2K5G4
- Manufacturer:
- Texas Instruments
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
INA155U/2K5G4.pdf
- Description:
- IC INST AMP 1 CIRCUIT 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,841
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Product details
Overview
INA155U/2K5G4 from Texas Instruments (formerly Burr-Brown) is a single-supply, rail-to-rail output CMOS instrumentation amplifier optimized for low-voltage sensor signal conditioning. It delivers fixed gains of 10 V/V or 50 V/V via pin strapping, features ±200 µV max input offset voltage, 550 kHz bandwidth at G = 10, and operates from +2.7 V to +5.5 V over –55°C to +125°C - enabling precision bridge and thermocouple amplification in industrial data acquisition systems.
For engineers reviewing the INA155U/2K5G4 datasheet, INA155U/2K5G4 pinout, INA155U/2K5G4 application, or INA155U/2K5G4 equivalent, key selection criteria include its rail-to-rail output swing within 10 mV of rails, ultra-low 0.2 pA typical input bias current, 5 µV/°C offset drift, and SO-8 package compatibility with high-density PCB layouts requiring stable gain accuracy across wide temperature ranges.
Technical Context
The INA155U/2K5G4 integrates two precision op amps and laser-trimmed thin-film resistors in a three-op-amp instrumentation topology. Its internal gain-setting network supports only two discrete configurations: open pins 1 and 8 for G = 10, or shorted pins 1 and 8 for G = 50 - no external resistor required for these modes.
It employs complementary CMOS input stages to achieve rail-to-rail common-mode input range (0.2 V to 2.5 V at VS = 2.7 V), while its class-AB output stage ensures <10 mV output swing from supply rails into 10 kΩ loads. The reference pin (Ref) sets output DC level and directly impacts input common-mode range validity.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Gain Options | Fixed 10 V/V (pins 1 & 8 open) or 50 V/V (pins 1 & 8 shorted); no external resistor needed for either setting |
| Input Offset Voltage | ±200 µV max at +25°C; enables sub-millivolt-level differential signal amplification without trimming |
| Offset Drift | ±5 µV/°C max; ensures stable DC accuracy across –55°C to +125°C operating range |
| Bandwidth (G = 10) | 550 kHz (–3 dB); sufficient for driving SAR ADCs sampling up to ~100 kSPS with minimal settling error |
| Slew Rate | 6.5 V/µs; supports fast transient response in dynamic sensor interfaces like position encoders |
| Input Bias Current | 0.2 pA typical; preserves signal integrity with high-impedance sources such as piezoelectric sensors |
| Supply Voltage Range | +2.7 V to +5.5 V; compatible with Li-ion, USB, and 3.3 V logic systems without level-shifting |
Pinout & Package
INA155U/2K5G4 is housed in an SOIC-8 (Package Drawing D) surface-mount package with standard 1.27 mm pitch, 5.0 mm × 6.2 mm body size, and JEDEC MS-012 compliant footprint.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (RG) | Gain select terminal | Connect to Pin 8 to set G = 50; leave open for G = 10; high-impedance node - must be low-Z for G = 50 |
| 2 (VIN–) | Inverting input | Differential input node; requires bias current return path (e.g., matched resistors to Ref or V–) |
| 3 (VIN+) | Non-inverting input | Differential input node; same bias current requirements as Pin 2 |
| 4 (V–) | Negative supply | Ground or negative rail; must be decoupled locally with 0.1 µF ceramic capacitor |
| 5 (Ref) | Output reference | DC level shift input; output = (VIN+ − VIN−) × G + VREF; must be low-impedance (≤200 Ω) for >90 dB CMRR |
| 6 (VOUT) | Amplified output | Rail-to-rail output capable of swinging within 10 mV of V+ or V– into ≥10 kΩ load |
| 7 (V+) | Positive supply | Single or dual supply rail; decouple locally with 0.1 µF ceramic capacitor |
| 8 (RG) | Gain select terminal | Paired with Pin 1; shorting Pins 1 & 8 configures G = 50; floating configures G = 10 |
Key Features
| Feature | Design Value |
|---|---|
| Rail-to-rail output swing | Within 10 mV of V+ or V– into 10 kΩ load - eliminates need for level-shifting when interfacing with 3.3 V ADCs |
| Laser-trimmed thin-film resistors | Ensures ±0.1% max gain error at G = 10 and ±0.25% at G = 50 - enables direct use in calibrated measurement systems |
| Ultra-low input bias current | 0.2 pA typical - prevents loading errors in high-Z sensor circuits (e.g., pH electrodes, piezoresistive bridges) |
| Wide common-mode input range | 0.2 V to 2.5 V at VS = 2.7 V - accommodates mid-supply common-mode voltages in single-supply bridge applications |
| Specified over extended temperature | Full parametric performance guaranteed from –55°C to +125°C - suitable for under-hood automotive and downhole industrial use |
Applications
| Bridge Sensor Amplifier | ECG Signal Conditioning |
|---|---|
Use Scenario: Amplifying microvolt-level differential signals from Wheatstone bridge strain gauges in load cells or pressure transducers powered from +5 V. IC Role / Device Role / Timing Role: Precision instrumentation amplifier providing fixed G = 10 or G = 50 gain, referenced to mid-supply for bipolar output swing. Use Value: ±200 µV offset and ±5 µV/°C drift ensure <0.1% full-scale error over temperature without recalibration. |
Use Scenario: Front-end amplification of low-amplitude, high-impedance biopotential signals from ECG electrodes in portable patient monitors. IC Role / Device Role / Timing Role: First-stage differential amplifier rejecting 50/60 Hz common-mode interference while preserving signal fidelity up to 150 Hz. Use Value: 0.2 pA input bias current prevents electrode polarization and DC drift; rail-to-rail output drives 12-bit SAR ADC directly. |
| Thermocouple Interface | PCMCIA Data Acquisition |
Use Scenario: Cold-junction compensated amplification of Type-K thermocouple outputs (≈41 µV/°C) in industrial temperature controllers. IC Role / Device Role / Timing Role: High-common-mode-rejection amplifier (92 dB min at G = 10) isolating small thermocouple voltage from noisy plant ground potentials. Use Value: 550 kHz bandwidth allows fast scan rates across multi-channel thermocouple arrays without phase lag. |
Use Scenario: Analog front-end for PCMCIA-based portable data loggers acquiring sensor data in field-deployed environmental monitoring units. IC Role / Device Role / Timing Role: Low-power, single-supply signal conditioner enabling compact, battery-operated designs with minimal external components. Use Value: +2.7 V to +5.5 V operation and 2.1 mA quiescent current extend battery life; SO-8 package fits tight PCMCIA card real estate. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar instrumentation amplifier applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| INA126P | Lower bandwidth (200 kHz), higher offset (±250 µV), but includes internal precision resistors for G = 5, 10, 100, 500 | Better suited for ultra-low-noise DC-coupled applications where gain flexibility outweighs speed needs | Select INA126P if programmable gain and lower noise density (11 nV/√Hz) are prioritized over bandwidth and rail-to-rail output |
| AD8221ARMZ | Higher bandwidth (825 kHz), lower drift (±0.3 µV/°C), but requires external gain resistor and consumes 1.2 mA more quiescent current | Preferred for high-precision, wide-temperature medical imaging systems needing tighter long-term stability | Select AD8221ARMZ when sub-µV/°C drift and >800 kHz bandwidth justify added external components and power budget |
Compared with INA155U/2K5G4, INA126P trades bandwidth and rail-to-rail output for broader gain options and lower noise, while AD8221ARMZ offers superior drift and speed at the cost of higher power and external resistor dependency.
Availability
INA155U/2K5G4 is available at Aetrix Electronics and suitable for industrial sensor amplifiers, medical biopotential monitoring, and PCMCIA data acquisition systems requiring stable component supply with extended temperature qualification and RoHS-compliant packaging.
Supply support for INA155U/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 acquired Burr-Brown in 2000 and maintains its precision analog portfolio, emphasizing high-performance signal chain solutions for industrial, medical, and test equipment markets.
The INA155 belongs to TI's legacy instrumentation amplifier family designed specifically for low-cost, single-supply sensor signal conditioning - balancing precision, speed, and ease-of-use in compact SO-8 and MSOP-8 packages.
FAQ
What gain options does the INA155U/2K5G4 support, and how are they configured?
The INA155U/2K5G4 supports only two factory-set gain options: 10 V/V and 50 V/V. Gain is selected by pin strapping - leaving pins 1 and 8 open configures G = 10; shorting them together configures G = 50. No external resistor is required for either mode, and the device does not support intermediate gains without adding external components that degrade accuracy.
Does the INA155U/2K5G4 require external passive components for basic operation?
Yes - the INA155U/2K5G4 requires local 0.1 µF ceramic decoupling capacitors on both V+ (Pin 7) and V– (Pin 4). Additionally, the Ref pin (Pin 5) must be driven by a low-impedance source (≤200 Ω) to maintain specified CMRR; a simple resistor divider from V+ to V– is insufficient unless buffered. Input bias current return paths are also mandatory for proper DC operation.
What is the maximum operating temperature range qualified for the INA155U/2K5G4?
The INA155U/2K5G4 is fully specified and guaranteed over –55°C to +125°C. This extended temperature range is validated per the datasheet's "SPECIFICATIONS: VS = +2.7V to +5.5V" table with boldface limits applying across this range, making it suitable for under-hood automotive, downhole oil/gas, and industrial control environments where thermal robustness is critical.
Can the INA155U/2K5G4 drive capacitive loads such as ADC inputs directly?
Yes - the INA155U/2K5G4 is characterized for stable operation with capacitive loads up to 100 pF, as confirmed in the "Settling Time" and "Overshoot vs Load Capacitance" typical curves. It directly drives capacitive-input SAR ADCs like the ADS7818 (12-bit, 500 kSPS) without isolation resistors, provided layout minimizes parasitic capacitance and the Ref pin remains low-impedance.
Is the INA155U/2K5G4 RoHS compliant and lead-free?
Yes - the INA155U/2K5G4 carries the "Green (RoHS & no Sb/Br)" eco plan designation per TI's Package Option Addendum, with NIPDAU lead finish and JEDEC MSL Level-2-260°C-1 year rating. It meets current EU RoHS requirements for all 10 restricted substances, including ≤0.1% by weight thresholds for lead, cadmium, mercury, and hexavalent chromium.
INA155U/2K5G4 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm 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:
- 6.5V/µs
- Gain Bandwidth Product:
- -
- -3db Bandwidth:
- 550 kHz
- Current - Input Bias:
- 1 pA
- Voltage - Input Offset:
- 200 µV
- Current - Supply:
- 1.7mA
- Current - Output / Channel:
- 50 mA
- Voltage - Supply Span (Min):
- 2.7 V
- Voltage - Supply Span (Max):
- 5.5 V
- Operating Temperature:
- -55°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
INA155U/2K5G4 FAQ
1.How can I place an order for INA155U/2K5G4 through Aetrix?
Please submit a Request for Quotation (RFQ) for INA155U/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 INA155U/2K5G4 reliable?
The price and inventory of INA155U/2K5G4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for INA155U/2K5G4 is usually 5 days.
3.What payment methods are accepted for INA155U/2K5G4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for INA155U/2K5G4 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for INA155U/2K5G4?
INA155U/2K5G4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your INA155U/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 INA155U/2K5G4?
For technical support, including INA155U/2K5G4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your INA155U/2K5G4 requirements.
6.How does Aetrix verify that INA155U/2K5G4 is sourced from the original manufacturer or authorized distributors?
All INA155U/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 INA155U/2K5G4 meets industry standards.
7.What is the process for return or replacement of INA155U/2K5G4?
All INA155U/2K5G4 units undergo pre-shipment inspection (PSI). If there is an issue with INA155U/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 INA155U/2K5G4 part is unused and in its original packaging.
Return procedure for INA155U/2K5G4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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