Texas Instruments OPA2156IDGKT

Overview

OPA2156IDGKT from Texas Instruments is a dual-channel, 36-V, rail-to-rail input/output CMOS precision operational amplifier optimized for high-fidelity signal conditioning in demanding industrial and instrumentation systems. It delivers ultra-low voltage noise (3 nV/√Hz at 10 kHz), low offset voltage (±25 µV), and wide gain-bandwidth product (25 MHz), enabling high-resolution data acquisition and photodiode transimpedance amplification with minimal distortion.

For engineers reviewing the OPA2156IDGKT datasheet, OPA2156IDGKT pinout, OPA2156IDGKT application, or OPA2156IDGKT equivalent, key selection criteria include its 3 nV/√Hz noise floor at 10 kHz, ±25 µV max offset, 40 V/µs slew rate, rail-to-rail I/O capability across ±2.25 V to ±18 V supplies, and VSSOP-8 packaging for space-constrained PCB layouts.

Technical Context

The OPA2156IDGKT employs a three-stage architecture with a low-noise PMOS input stage, feed-forward path, and high-current output stage-enabling simultaneous low noise, low distortion, and fast settling (600 ns to 0.01%). Its phase-reversal protection prevents output inversion when inputs exceed common-mode range, critical for noninverting sensor interfaces.

It operates over –40°C to +125°C with ±0.5 µV/°C offset drift and supports dual-supply (±2.25 V to ±18 V) or single-supply (4.5 V to 36 V) configurations. Input bias current remains ultra-low (±5 pA typical), preserving signal integrity in high-impedance photodiode and vibration sensor front-ends.

Key Specifications

Pinout & Package

VSSOP-8 package (3.00 mm × 3.00 mm body size), thermally enhanced for high-power-density applications in compact industrial modules.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar precision op amp applications.

Compared with OPA2156IDGKT, OPA2182IDGKT trades bandwidth and ruggedness for lower noise and offset, while ADA4522-2ARMZ sacrifices speed for near-zero drift-making OPA2156IDGKT the balanced choice for wideband, high-accuracy industrial signal chains requiring both precision and robustness.

Availability

OPA2156IDGKT is available at Aetrix Electronics and suitable for data acquisition systems, photodiode transimpedance amplifiers, and vibration monitor modules requiring stable component supply across extended temperature ranges and multi-year production cycles.

Supply support for OPA2156IDGKT 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 specializing in analog and embedded processing technologies, with decades of expertise in precision amplifiers and industrial-grade IC design.

The OPA2156IDGKT belongs to TI's high-voltage precision op amp family, engineered specifically for 36-V industrial signal chains where low noise, rail-to-rail operation, and robust overvoltage tolerance are mandatory.

FAQ

What is the maximum operating temperature range for the OPA2156IDGKT?

The OPA2156IDGKT is specified over the industrial temperature range of –40°C to +125°C. This rating applies to both SOIC and VSSOP packages per the official TI SBOS900B datasheet, and thermal derating is required above 125°C junction temperature. The device includes thermal protection that activates at 170°C to prevent permanent damage, making it suitable for harsh-environment applications such as motor control cabinets and outdoor instrumentation enclosures. OPA2156IDGKT maintains full electrical specifications across this entire range.

Does the OPA2156IDGKT support single-supply operation?

Yes, the OPA2156IDGKT supports true single-supply operation from 4.5 V to 36 V, with rail-to-rail input and output stages enabling full utilization of the supply voltage range. When operated from a 5-V or 24-V rail, it achieves common-mode input range from V– – 0.1 V to V+ + 0.1 V and output swing within 200 mV of each rail. This eliminates the need for dual supplies in many industrial and portable applications. OPA2156IDGKT retains all key specs-including 3 nV/√Hz noise and ±25 µV offset-under single-supply conditions.

What is the purpose of phase-reversal protection in the OPA2156IDGKT?

Phase-reversal protection in the OPA2156IDGKT prevents output polarity inversion when input voltages exceed the linear common-mode range-a failure mode common in noninverting amplifier configurations during sensor overvoltage events. Instead of reversing, the output saturates cleanly at the nearest rail. This behavior avoids catastrophic control loop errors in safety-critical systems like PLC analog outputs or medical infusion pumps. OPA2156IDGKT implements this via internal circuitry that clamps rather than inverts, as verified in Figure 42 of the SBOS900B datasheet.

Can the OPA2156IDGKT drive capacitive loads without instability?

The OPA2156IDGKT is unity-gain stable and can drive moderate capacitive loads (≤100 pF) directly, but larger loads require isolation resistors (e.g., 25 Ω–50 Ω in series with the output) to maintain phase margin above 45°. Figure 28 in the SBOS900B datasheet shows phase margin vs. capacitive load, confirming stable operation up to 1 nF with R_ISO = 50 Ω. For cable driving or ADC input buffering, this technique preserves 600 ns settling time while preventing peaking or oscillation. OPA2156IDGKT's robust layout guidelines emphasize local decoupling and short traces to minimize parasitic capacitance.

How does the OPA2156IDGKT compare to standard precision op amps in photodiode applications?

In photodiode transimpedance applications, the OPA2156IDGKT outperforms standard precision op amps due to its combination of ultra-low input bias current (±5 pA), low voltage noise (3 nV/√Hz), and rail-to-rail output-enabling high transimpedance gains (>100 MΩ) without saturation or added noise degradation. Unlike bipolar-input op amps, its CMOS input avoids leakage-induced dark current errors. Its 25-MHz GBW also supports wider bandwidths than legacy precision parts (e.g., OP07), allowing faster response to light pulses. OPA2156IDGKT is explicitly recommended by TI for photodiode TIA use in Section 2 of SBOS900B.