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Texas Instruments INA155UA
- Part No.:
- INA155UA
- Manufacturer:
- Texas Instruments
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
INA155UA.pdf
- Description:
- IC INST AMP 1 CIRCUIT 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,815
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Product details
Overview
INA155UA 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, ±200 µV max input offset voltage, 550 kHz bandwidth at G = 10, and operates from +2.7 V to +5.5 V across –55°C to +125°C - enabling high-accuracy bridge and thermocouple amplification in industrial data acquisition systems.
For engineers reviewing the INA155UA datasheet, INA155UA pinout, INA155UA application, or INA155UA 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, internal gain configuration (no external resistors required for G = 10/50), guaranteed operation over extended temperature, and SO-8 package compatibility with legacy PCB layouts.
Technical Context
The INA155UA implements a three-op-amp topology with complementary CMOS input stages enabling rail-to-rail common-mode input range and output swing. Its internal laser-trimmed resistor network sets precise gain ratios (10 or 50), while the reference pin (Ref) establishes output DC level and directly influences input common-mode range boundaries.
Gain selection is implemented via pins 1 and 8: open for G = 10 (±0.1% gain error), shorted for G = 50 (±0.25% gain error). The device uses class-AB output stage architecture to achieve <10 mV output swing from supply rails under 10 kΩ load, and features ESD-protected inputs rated for ±0.5 V beyond supplies.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Gain Options | Fixed 10 V/V or 50 V/V via pin strapping - eliminates external gain-setting resistor for standard configurations |
| Input Offset Voltage | ±200 µV max (–55°C to +125°C) - enables sub-millivolt-level DC-coupled sensor measurements without trimming |
| Input Bias Current | 0.2 pA typical - supports high-impedance sources like piezoelectric sensors and pH electrodes without loading error |
| Bandwidth (G = 10) | 550 kHz - sufficient for driving 500 kSPS SAR ADCs (e.g., ADS7818) with minimal settling delay |
| Rail-to-Rail Output | Swing within 5–10 mV of V+ and V– rails (RL ≥ 10 kΩ) - maximizes dynamic range in single-supply 3.3 V or 5 V systems |
| Supply Range | +2.7 V to +5.5 V - compatible with Li-ion battery, USB-powered, and industrial 3.3 V/5 V rails |
| Operating Temp | –55°C to +125°C - qualified for under-hood automotive, downhole, and industrial control environments |
Pinout & Package
INA155UA is housed in an SO-8 surface-mount package (JEDEC MS-012, TI drawing D), with thermal resistance θJA = 150°C/W. Pin 1 is marked by a beveled corner or dot; pin numbering follows standard SOIC convention (counterclockwise from pin 1).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (RG) | Gain select terminal | Connect to pin 8 for G = 50; leave open for G = 10 - determines internal feedback ratio without external components |
| 2 (VIN–) | Inverting input | Differential input node; requires low-impedance bias path (e.g., matched resistors) for optimal CMRR |
| 3 (VIN+) | Non-inverting input | Differential input node; same bias requirements as VIN– to maintain balance and minimize offset drift |
| 4 (V–) | Negative supply | Ground or negative rail connection; must be decoupled locally with 0.1 µF ceramic capacitor |
| 5 (Ref) | Output reference | Sets output DC level (e.g., VS/2); impedance ≤ 200 Ω required to preserve >92 dB CMRR at G = 10 |
| 6 (VOUT) | Amplified output | Single-ended output referenced to Ref; capable of driving 100 pF capacitive loads directly into ADC inputs |
| 7 (V+) | Positive supply | +2.7 V to +5.5 V supply; requires local 0.1 µF decoupling adjacent to pin |
| 8 (RG) | Gain select terminal | Paired with pin 1; shorting creates G = 50 path - trace impedance must be <20 Ω to avoid 0.2% gain shift |
Key Features
| Feature | Design Value |
|---|---|
| Laser-trimmed precision gain | Guaranteed ±0.1% gain error at G = 10 ensures accurate scaling of bridge outputs without calibration |
| Rail-to-rail output stage | Delivers full 0–5.49 V output swing on +5.5 V supply - preserves >99% of ADC input range in single-supply systems |
| Ultra-low input bias current | 0.2 pA typical enables use with >100 MΩ source impedances (e.g., RTD sense leads, electrophysiology electrodes) |
| Extended temperature qualification | Specified over –55°C to +125°C - supports deployment in unheated enclosures and engine compartments |
| Low-noise architecture | 40 nV/√Hz voltage noise density at 1 kHz - maintains SNR > 80 dB for 20-bit ADC interfacing at 10 kHz bandwidth |
Applications
| Industrial Sensor Amplifiers | Medical Instrumentation |
|---|---|
Use Scenario: Amplifying millivolt-level differential signals from Wheatstone bridge pressure transducers in factory-floor PLC analog input modules. IC Role / Device Role / Timing Role: Precision instrumentation amplifier providing fixed 10× gain, rail-to-rail output, and 550 kHz bandwidth to drive 16-bit SAR ADCs at 100 kSPS. Use Value: Eliminates need for external gain resistors and offset trim circuits, reducing BOM count and layout area while maintaining ±0.02% gain accuracy over temperature. | Use Scenario: Front-end amplification of ECG electrode signals in portable patient monitors with 3.3 V battery supply. IC Role / Device Role / Timing Role: Low-bias-current, low-noise IA conditioning biopotential signals prior to anti-alias filtering and digitization. Use Value: 0.2 pA input bias prevents electrode polarization errors; rail-to-rail output maximizes dynamic range into 3.3 V ADC, improving resolution for microvolt-level ST-segment detection. |
| Driving A/D Converters | PCMCIA Data Acquisition Cards |
Use Scenario: Direct interface between strain-gauge bridge and high-speed 12-bit ADC (ADS7818, 500 kSPS) in vibration analysis equipment. IC Role / Device Role / Timing Role: Buffering and gain-setting stage with 6.5 V/µs slew rate and 5 µs 0.1% settling time to support full throughput without missing codes. Use Value: Internal gain configuration avoids parasitic capacitance from external resistors, preserving phase margin and enabling stable 100 pF capacitive loading at ADC input. | Use Scenario: Compact signal conditioning for modular PCMCIA-based data loggers used in field-deployed environmental monitoring. IC Role / Device Role / Timing Role: Single-chip solution for amplifying thermocouple and RTD outputs with programmable gain (10/50) and reference-level control. Use Value: SO-8 footprint matches legacy designs; wide supply range (+2.7 V to +5.5 V) accommodates variable PCMCIA bus voltage; –55°C to +125°C rating ensures reliability in outdoor enclosures. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar instrumentation amplifier applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| INA126PA | G = 5–10,000 via external RG; higher 250 µV max offset; 1.2 mA IQ vs 2.1 mA | Requires external gain resistor; better for variable-gain systems but less precise at fixed G = 10/50 | Select when programmable gain >50 or lower quiescent current is critical; not drop-in for pin-strapped INA155UA layouts |
| AD8221ARMZ | G = 10–1000 via RG; 25 µV max offset; 1.1 mA IQ; MSOP-8 only | Superior DC precision and lower noise, but requires external RG and lacks SO-8 option | Choose for highest accuracy (<1 µV/°C drift) in medical or test equipment; requires PCB redesign due to MSOP-8 and different pinout |
Compared with INA155UA, INA126PA offers wider gain flexibility at the cost of reduced DC accuracy and added component count, while AD8221ARMZ delivers superior offset performance but mandates layout changes and external gain configuration - making INA155UA optimal for cost-sensitive, fixed-gain industrial sensor nodes where SO-8 compatibility and simplicity are prioritized.
Availability
INA155UA is available at Aetrix Electronics and suitable for industrial sensor amplifiers, medical instrumentation, and A/D converter driving applications requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant SO-8 packaging.
Supply support for INA155UA 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 full product support, manufacturing, and documentation for the INA155 series. TI is a global semiconductor leader specializing in analog and embedded processing solutions.
The INA155 product line was designed specifically for low-cost, high-precision signal conditioning in resource-constrained industrial and portable systems - emphasizing rail-to-rail operation, fixed-gain simplicity, and extended temperature reliability without external passive components.
FAQ
What is the maximum operating supply voltage for the INA155UA?
The INA155UA has an absolute maximum supply voltage of 7.5 V across V+ and V– terminals. However, its specified operating range is +2.7 V to +5.5 V. Operation above +5.5 V voids parametric guarantees and may degrade long-term reliability. For designs requiring >5.5 V rails, consider the INA155U/UA's absolute maximum rating as a safety margin only - not a functional specification. Always refer to the latest TI datasheet SBOS114 for derating curves.
Can the INA155UA be used with dual supplies?
Yes, the INA155UA supports dual-supply operation (e.g., ±2.5 V) as well as single-supply configurations. When using dual supplies, the Ref pin should be tied to ground or a mid-supply reference to set output common-mode level. Input common-mode range extends to within 0.3 V of either rail, and rail-to-rail output swing remains functional. The device's internal architecture does not require V– to be at ground potential - enabling flexible biasing in bipolar signal chains.
How do I configure the INA155UA for G = 50?
To configure the INA155UA for G = 50, connect pin 1 (RG) directly to pin 8 (RG) using a low-impedance trace (<20 Ω). Do not use a resistor - a direct metal connection is required. This shorts the internal gain-setting node, selecting the 50 V/V ratio. Confirm continuity with a multimeter before power-up. Note that gain error increases to ±0.25% (vs ±0.1% at G = 10), and CMRR degrades slightly - verify performance in your specific layout using the test conditions in SBOS114 Section 6.3.
Is the INA155UA RoHS compliant and lead-free?
Yes, the INA155UA is RoHS compliant and lead-free. Per TI's Package Option Addendum (Feb 2020), it carries "Green (RoHS & no Sb/Br)" eco-plan status with NIPDAU (nickel-palladium-gold) lead finish and JEDEC Level-2 moisture sensitivity rating. The device marking "INA155U A" appears on the top surface, and full compliance documentation (including substance declarations and test reports) is available via TI's Quality & Environmental Information portal using orderable part number INA155UA.
What is the recommended decoupling for the INA155UA?
TI recommends a 0.1 µF ceramic capacitor placed as close as possible to both V+ (pin 7) and V– (pin 4), with short, low-inductance traces to the ground plane. For noisy supply environments, add a 10 µF tantalum or aluminum electrolytic capacitor in parallel near the board edge. Avoid shared vias between decoupling caps and other ICs. The Ref pin (pin 5) also requires a low-impedance path - if driven by a divider, use ≤200 Ω total Thevenin resistance or buffer with an op amp to prevent CMRR degradation.
INA155UA Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- 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
INA155UA FAQ
1.How can I place an order for INA155UA through Aetrix?
Please submit a Request for Quotation (RFQ) for INA155UA 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 INA155UA reliable?
The price and inventory of INA155UA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for INA155UA is usually 5 days.
3.What payment methods are accepted for INA155UA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for INA155UA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for INA155UA?
INA155UA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your INA155UA 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 INA155UA?
For technical support, including INA155UA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your INA155UA requirements.
6.How does Aetrix verify that INA155UA is sourced from the original manufacturer or authorized distributors?
All INA155UA 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 INA155UA meets industry standards.
7.What is the process for return or replacement of INA155UA?
All INA155UA units undergo pre-shipment inspection (PSI). If there is an issue with INA155UA, 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 INA155UA part is unused and in its original packaging.
Return procedure for INA155UA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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