Texas Instruments INA155E/2K5

Overview

INA155E/2K5 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 - optimized for low-voltage sensor signal conditioning in industrial bridge and RTD measurement systems.

For engineers reviewing the INA155E/2K5 datasheet, INA155E/2K5 pinout, INA155E/2K5 application, or INA155E/2K5 equivalent, key selection criteria include guaranteed –55°C to +125°C operation, MSOP-8 package compatibility, rail-to-rail output swing within 10mV of rails, 0.2pA typical input bias current, and internal gain-setting architecture requiring no external resistors for G=10 or G=50 configurations.

Technical Context

The INA155E/2K5 implements a three-op-amp topology with complementary CMOS input stages enabling rail-to-rail common-mode input range and rail-to-rail output swing. Its internal laser-trimmed resistor network fixes gain at 10V/V (RG pins open) or 50V/V (RG pins shorted), eliminating external gain-setting components while maintaining ±0.1% gain error at G=10 and ±0.25% at G=50 over temperature.

Designed for single-supply operation from +2.7V to +5.5V, the device uses a low-impedance reference terminal (Ref) to set output common-mode level, supporting direct interfacing to SAR ADCs like ADS7818. Input protection diodes clamp signals to V± ±0.5V, and ESD robustness meets JEDEC JS-001 Class 2 requirements.

Key Specifications

Pinout & Package

INA155E/2K5 is packaged in an 8-pin MSOP (VSSOP-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 INA126UA/2K5 and AD8421ARMZ-REEL7, the INA155E/2K5 uniquely balances fixed-gain simplicity, rail-to-rail output, and extended temperature operation in a space-constrained MSOP-8 package - making it optimal for cost-sensitive, high-volume industrial sensor nodes where 550kHz bandwidth and ±5µV/°C drift are sufficient.

Availability

INA155E/2K5 is available at Aetrix Electronics and suitable for industrial sensor amplifiers, medical ECG front-ends, and PCMCIA data acquisition systems requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for INA155E/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 acquired Burr-Brown in 2000 and maintains its precision analog portfolio, emphasizing high-performance signal chain ICs for industrial, medical, and test equipment markets.

The INA155 product line was designed specifically for low-cost, single-supply instrumentation amplifier applications requiring rail-to-rail output, fixed gain, and operation from –55°C to +125°C - targeting bridge-based sensors and portable data acquisition.

FAQ

What is the maximum operating supply voltage for the INA155E/2K5?

The INA155E/2K5 has an absolute maximum supply voltage of 7.5V between V+ and V–, but its specified operating range is +2.7V to +5.5V. Operation beyond +5.5V voids parametric guarantees, and exceeding 7.5V risks permanent damage. The device draws 1.7–2.1mA quiescent current within its specified range, making it suitable for battery-powered 3.3V or 5V systems.

How does the INA155E/2K5 achieve rail-to-rail output swing?

The INA155E/2K5 uses a class AB output stage with complementary n- and p-channel MOSFETs to achieve rail-to-rail output swing within 5mV of the supply rails under 10kΩ load. This architecture allows full utilization of the supply voltage range - critical for maximizing SNR in low-voltage ADC interfaces. Performance degrades slightly at heavier loads or extreme temperatures, as shown in the "Output Voltage Swing vs Output Current" curve.

Can the INA155E/2K5 be used with dual power supplies?

Yes, the INA155E/2K5 supports dual-supply operation (e.g., ±2.5V) in addition to single-supply mode. Its input common-mode range extends to within 0.3V of either rail, and the Ref pin can be set to any voltage between V– and V+ to define output common-mode level. However, the device's rail-to-rail output and low-voltage optimization make it most effective in single-supply configurations from +2.7V to +5.5V.

What is the purpose of the Ref pin on the INA155E/2K5?

The Ref pin on the INA155E/2K5 sets the output common-mode voltage: VOUT = G × (VIN+ − VIN−) + VREF. It must be driven by a low-impedance source (<200Ω) to maintain ≥80dB CMRR. Typical use ties Ref to VS/2 for symmetric output swing in single-supply systems. Applying a fixed DC voltage here enables level-shifting without external op amps - simplifying interface to unipolar ADCs.

Is the INA155E/2K5 pin-compatible with other Burr-Brown instrumentation amplifiers?

No, the INA155E/2K5 is not pin-compatible with other Burr-Brown instrumentation amplifiers such as the INA128 or INA118. Its unique RG pin strapping (pins 1 and 8) for fixed gain, combined with dedicated Ref and V– terminals, defines a distinct pinout. Substitution requires PCB layout revision. Always verify pin functions against the official INA155E/2K5 datasheet before replacement.