Texas Instruments LMC6081IMX/NOPB

Overview

LMC6081IMX/NOPB from Texas Instruments is a precision single-channel CMOS operational amplifier optimized for ultra-low-input-bias-current (10 fA), low-offset-voltage (150 µV typical), and rail-to-rail output swing (within 20 mV of rails at 2 kΩ load) in single-supply systems (4.5 V to 15.5 V). It serves as a high-impedance signal conditioner in photodiode preamplifiers, medical instrumentation front-ends, and piezoelectric charge amplifiers.

For engineers reviewing the LMC6081IMX/NOPB datasheet, LMC6081IMX/NOPB pinout, LMC6081IMX/NOPB application, or LMC6081IMX/NOPB equivalent, key selection criteria include input bias current stability over temperature, common-mode range extending to V–, open-loop gain (123 dB), PSRR (≥75 dB), and SOIC-8 thermal performance (R_θJA = 193°C/W).

Technical Context

The LMC6081IMX/NOPB employs a proprietary CMOS input stage enabling femtoampere-level input bias current and full rail-to-rail output swing without compromising voltage gain or phase margin. Its input common-mode range includes V–, supporting true single-supply operation down to ground-referenced sensors.

It features internal compensation for stable operation with capacitive loads up to 100 pF when used with recommended pull-up resistors, and incorporates latch-up immunity enhancements via process-level SCR suppression-critical for high-impedance transducer interfaces where transient overvoltage or ESD events may occur.

Key Specifications

Pinout & Package

LMC6081IMX/NOPB is housed in an 8-pin SOIC (D package) with standard JEDEC MS-012AC footprint (5.3 mm × 6.2 mm, 1.27 mm pitch). Thermal resistance is R_θJA = 193°C/W on 2-layer PCB per TI SNOS630E.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LMC6061IMX/NOPB and OPA333AIDBVR, LMC6081IMX/NOPB uniquely balances femtoampere input bias current, 1.3 MHz bandwidth, and rail-to-rail output-making it optimal for precision, high-impedance, moderate-speed signal chains where both leakage and bandwidth matter.

Availability

LMC6081IMX/NOPB is available at Aetrix Electronics and suitable for photodiode preamplification, medical instrumentation front-ends, and piezoelectric charge amplification requiring stable component supply across production lifecycles.

Supply support for LMC6081IMX/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 delivering analog, embedded processing, and connectivity solutions for industrial, automotive, and personal electronics markets.

The LMC608x family was designed specifically for precision, low-leakage signal conditioning in single-supply instrumentation-targeting applications where input bias current, offset voltage, and rail-to-rail operation are simultaneously critical.

FAQ

What is the maximum capacitive load the LMC6081IMX/NOPB can drive directly?

The LMC6081IMX/NOPB is not characterized for direct capacitive load driving. Per TI SNOS630E Section 6.1.3, stable operation with >100 pF loads requires external compensation-either a pull-up resistor to V+ (≥500 µA current) or RC network at the output. Direct connection to ADC input capacitance (typically 10–20 pF) is acceptable without compensation, but larger loads require mitigation to avoid oscillation or overshoot.

Does the LMC6081IMX/NOPB support dual-supply operation?

Yes, the LMC6081IMX/NOPB supports dual-supply operation from ±2.25 V to ±7.75 V, as specified in Recommended Operating Conditions (Section 5.3). Its input common-mode range extends to V–, and output swings rail-to-rail relative to both supplies-enabling symmetric signal handling in traditional op amp topologies like inverting amplifiers or active filters.

How does the input bias current of the LMC6081IMX/NOPB vary with temperature?

Per Electrical Characteristics (Section 5.7), input bias current is ±10 fA typical at 25°C and increases to ±4 pA maximum over –40°C to +85°C. This represents a 400× increase at temperature extremes-but remains among the lowest available for precision op amps, preserving usability in thermally varying environments like portable medical devices or outdoor sensors.

Is the LMC6081IMX/NOPB pin-compatible with other LMC608x variants?

No-LMC6081IMX/NOPB (single-channel, SOIC-8) has different pinout than LMC6082 (dual-channel, SOIC-8) and LMC6084 (quad-channel, SOIC-14). Pin functions for LMC6081IMX/NOPB are defined in Table 4-1: +IN (Pin 3), –IN (Pin 2), OUT (Pin 6), V+ (Pin 7), V– (Pin 4), and NC (Pins 1, 5, 8). Substitution requires PCB redesign.

What layout practices are essential to achieve the specified 10 fA input bias current in the LMC6081IMX/NOPB?

To realize the 10 fA input bias current, implement guard rings around +IN and –IN traces connected to the same potential as the inputs (e.g., buffered reference), use clean FR-4 with solder mask over non-ground planes, avoid conformal coating near inputs, and minimize contamination. TI recommends air-wiring input pins when ultimate leakage performance is required-bending pins upward and connecting directly to components to eliminate PCB surface leakage paths that dominate at femtoampere levels.