Texas Instruments INA155E/250

Overview

INA155E/250 from Texas Instruments (formerly Burr-Brown) is a single-supply, rail-to-rail output CMOS instrumentation amplifier with fixed gain options of 10V/V or 50V/V, ±200µV max input offset voltage, ±5µV/°C drift, and 550kHz bandwidth at G=10. It operates from +2.7V to +5.5V and is specified over –55°C to +125°C for industrial sensor signal conditioning.

For engineers reviewing the INA155E/250 datasheet, INA155E/250 pinout, INA155E/250 application, or INA155E/250 equivalent, key selection criteria include rail-to-rail output swing within 10mV of rails, ultra-low input bias current (0.2pA typ), CMRR ≥92dB at G=10, and MSOP-8 package compatibility with high-density PCB layouts.

Technical Context

The INA155E/250 implements a three-op-amp architecture with internal laser-trimmed thin-film resistors enabling precise fixed gains. Its rail-to-rail output stage uses complementary common-source transistors, supporting low-voltage A/D converter driving without external level-shifting.

Gain selection is implemented via pin strapping: open pins 1 and 8 yields G=10 (±0.1% gain error), shorting them yields G=50 (±0.25% gain error); intermediate gains require an external resistor RG per G = 10 + 400kΩ/(10kΩ + RG). Input common-mode range depends on reference voltage and output level, with degradation above (V+) – 1.8V.

Key Specifications

Pinout & Package

INA155E/250 is housed in an 8-pin VSSOP (MSOP-8) package (drawing DGK), 3.0mm × 3.0mm footprint, 0.65mm pitch, RoHS-compliant, moisture sensitivity level 2 (260°C peak reflow).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar instrumentation amplifier applications.

Compared with INA126PA and AD8221ARMZ, the INA155E/250 offers the lowest component count for fixed-gain sensor interfaces, smallest PCB footprint among precision instrumentation amplifiers, and best balance of rail-to-rail output, ultra-low bias current, and extended temperature specification in MSOP-8.

Availability

INA155E/250 is available at Aetrix Electronics and suitable for industrial sensor amplifiers, medical ECG front-ends, and PCMCIA data acquisition systems requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for INA155E/250 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 INA155E/250 belongs to TI's instrumentation amplifier product line, designed specifically for low-voltage, single-supply sensor signal conditioning where rail-to-rail output, low drift, and minimal external components are critical.

FAQ

What gain options does the INA155E/250 support, and how are they configured?

The INA155E/250 supports two fixed gain options: 10V/V and 50V/V. Gain is selected by hardware pin strapping - leaving pins 1 and 8 open configures G=10, while shorting them together configures G=50. No external resistors are needed for these standard gains, simplifying layout and improving reliability. The INA155E/250 datasheet specifies ±0.1% gain error at G=10 and ±0.25% at G=50 over temperature.

Does the INA155E/250 require external offset trimming in typical applications?

No, the INA155E/250 does not require external offset trimming in most applications. It features laser-trimmed input offset voltage (±200µV max) and low drift (±5µV/°C), making it suitable for precision DC-coupled measurements without adjustment. The reference pin (Pin 6) can optionally apply a correction voltage if fine-tuning is needed, but this is rarely necessary. The INA155E/250's factory calibration ensures consistent performance across production lots.

What is the maximum operating temperature range for the INA155E/250, and is it qualified for automotive use?

The INA155E/250 is fully specified over –55°C to +125°C and operates reliably from –65°C to +150°C. While not AEC-Q200 qualified, its extended temperature rating and robust construction make it suitable for under-hood automotive sensor interfaces such as exhaust gas oxygen or manifold absolute pressure sensing, provided system-level qualification is performed. The INA155E/250's guaranteed performance across this range eliminates derating concerns in harsh thermal environments.

Can the INA155E/250 drive ADC inputs directly, and what load conditions ensure stability?

Yes, the INA155E/250 is optimized to drive capacitive-input ADCs directly. Its 6.5V/µs slew rate and rail-to-rail output allow clean step response into typical CDAC loads (e.g., 10–100pF). Stability is maintained with capacitive loads up to 100pF, as verified in the INA155E/250 typical performance curves. For heavier loads, a small series resistor (≤10Ω) isolates the output capacitance without degrading bandwidth significantly.

What package type and footprint does the INA155E/250 use, and are there thermal considerations?

The INA155E/250 uses an 8-pin VSSOP (MSOP-8) package (drawing DGK), measuring 3.0mm × 3.0mm with 0.65mm lead pitch. Its thermal resistance θJA is 150°C/W. For continuous operation at full ambient temperature (e.g., +125°C), power dissipation should remain below 16.7mW (calculated from (125°C − 25°C)/150°C/W). Layout best practices include using thermal vias under the exposed pad (if present) and minimizing trace length to decoupling capacitors.