Texas Instruments LMP7731MFE/NOPB

Overview

LMP7731MFE/NOPB from Texas Instruments is a single-channel, rail-to-rail input/output precision operational amplifier optimized for low-noise, high-accuracy signal conditioning in low-voltage systems. It delivers 2.9 nV/√Hz input voltage noise at 1 kHz, 22 MHz gain bandwidth, and ±1.5 nA input bias current across 1.8 V to 5.5 V supply, enabling high-fidelity sensor front-end amplification in photometric instrumentation.

For engineers reviewing the LMP7731MFE/NOPB datasheet, LMP7731MFE/NOPB pinout, LMP7731MFE/NOPB application, or LMP7731MFE/NOPB equivalent, key selection criteria include its 3 Hz 1/f noise corner, 130 dB CMRR, rail-to-rail output swing within 13 mV of rails (RL = 2 kΩ), and validated performance across −40°C to +125°C industrial temperature range.

Technical Context

The LMP7731MFE/NOPB employs a proprietary bipolar input stage with integrated input bias current cancellation circuitry, achieving ±1.5 nA bias while retaining low voltage noise-uncommon in bipolar-input op-amps. Its 1/f corner at 3 Hz ensures stable DC accuracy for precision measurement.

It features a wide 22 MHz gain-bandwidth product with 60° phase margin (CL = 20 pF, RL = 10 kΩ), supporting stable closed-loop gains up to 100× without compensation. The rail-to-rail input extends common-mode range to 0 V–VS, and rail-to-rail output delivers >99% supply swing under 2 kΩ load.

Key Specifications

Pinout & Package

The LMP7731MFE/NOPB is packaged in a 5-pin SOT-23 surface-mount package (JEDEC MO-178AB), footprint-compatible with industry-standard 5-pin op-amp layouts and optimized for space-constrained portable designs.

Key Features

Applications

Equivalent & Alternatives

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

Compared with OPA333AIDBVR and ADA4625-1ARMZ, the LMP7731MFE/NOPB uniquely balances ultra-low voltage noise (2.9 nV/√Hz), low bias current (±1.5 nA), and 22 MHz bandwidth in a 1.8–5.5 V supply envelope-making it optimal for high-speed, high-resolution photometric and gas-sensing front-ends where both noise and speed constrain system SNR.

Availability

LMP7731MFE/NOPB is available at Aetrix Electronics and suitable for photometric instrumentation, gas analysis instruments, and medical instrumentation requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for LMP7731MFE/NOPB 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 investment in precision amplifier design and characterization.

The LMP7731MFE/NOPB belongs to TI's LMP™ precision amplifier family, engineered specifically for low-noise, rail-to-rail, low-voltage signal conditioning in sensor interfaces where DC accuracy, bandwidth, and power efficiency are simultaneously critical.

FAQ

What is the 1/f noise corner frequency of the LMP7731MFE/NOPB, and why does it matter for DC precision?

The LMP7731MFE/NOPB has a 1/f noise corner at 3 Hz. This exceptionally low corner means voltage noise remains near its broadband value (2.9 nV/√Hz) down to near-DC frequencies, minimizing low-frequency drift and enabling accurate long-integration measurements-critical in gas analysis and photometric applications where signal bandwidth is often <10 Hz.

Can the LMP7731MFE/NOPB drive capacitive loads directly, and what is the maximum recommended capacitance?

The LMP7731MFE/NOPB is not unity-gain stable with large capacitive loads. For reliable operation, capacitive loads should be limited to ≤20 pF when used in unity-gain configuration. For larger loads (e.g., ADC input capacitors), an isolation resistor (≥100 Ω) between LMP7731MFE/NOPB output and the capacitor is required to maintain phase margin and prevent oscillation.

How does the input bias current cancellation circuit in the LMP7731MFE/NOPB work, and what benefit does it provide?

The LMP7731MFE/NOPB uses proprietary circuitry that actively cancels input bias current in its bipolar input stage, reducing net IB to ±1.5 nA. This allows the device to combine the low voltage noise of bipolar inputs with MOSFET-like bias performance-enabling accurate amplification of high-impedance sensor signals (e.g., pH probes, photodiodes) without significant DC error.

Is the LMP7731MFE/NOPB suitable for single-supply operation with rail-to-rail input and output, and what is its guaranteed common-mode range?

Yes, the LMP7731MFE/NOPB supports true single-supply operation with rail-to-rail input (0 V to V_S) and output (within 13 mV of either rail). Its guaranteed common-mode voltage range is 0 V to V_S, and large-signal CMRR remains ≥80 dB across this full range-validated per datasheet Figure 18–20 and Electrical Characteristics tables.

What is the maximum output current capability of the LMP7731MFE/NOPB, and how does it vary with supply voltage?

The LMP7731MFE/NOPB delivers ±33 mA output current (sourcing/sinking) at V_S = 5 V and ±28 mA at V_S = 3.3 V, per Electrical Characteristics tables. Output drive strength scales with supply voltage due to internal current-limiting architecture, ensuring robust loading capability across its full 1.8–5.5 V operating range.