Texas Instruments LMC6081IM/NOPB

Overview

LMC6081IM/NOPB from Texas Instruments is a precision single-channel CMOS operational amplifier optimized for ultra-low-input-bias-current signal conditioning in high-impedance sensor interfaces. It delivers 150 μV typical offset voltage, 10 fA typical input bias current, rail-to-rail output swing within 20 mV of supply rails (at 2 kΩ load), and operates from 4.5 V to 15.5 V single supply - enabling accurate photodiode preamplification and medical transducer amplification without dual-rail complexity.

For engineers reviewing the LMC6081IM/NOPB datasheet, LMC6081IM/NOPB pinout, LMC6081IM/NOPB application, or LMC6081IM/NOPB equivalent, key selection criteria include verified input bias current stability over temperature, guaranteed output swing margin at 2 kΩ and 600 Ω loads, confirmed SOIC-8 package thermal resistance (193 °C/W), and documented compatibility with RES11A matched resistor networks in instrumentation amplifier topologies.

Technical Context

The LMC6081IM/NOPB employs a proprietary CMOS input stage with guarded differential pair architecture to achieve 10 fA input bias current while maintaining 123 dB open-loop gain and 1.3 MHz gain-bandwidth product. Its rail-to-rail output stage uses complementary push-pull drivers with internal compensation tuned for stability with ≥600 Ω resistive loads and moderate capacitive loads when externally compensated.

Input common-mode range extends to V– (ground in single-supply mode), supporting true ground-referenced sensing; PSRR exceeds 75 dB (positive) and 84 dB (negative) at 25 °C, ensuring robust operation in noisy supply environments typical of portable instrumentation and industrial sensor nodes.

Key Specifications

Pinout & Package

LMC6081IM/NOPB is housed in an 8-pin SOIC (D package) with exposed pad not present; thermal resistance is 193 °C/W (junction-to-ambient). Pin 1, 5, and 8 are no-connect (NC) and must remain unconnected or floating.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LMC6081IM/NOPB, LMC6062IM/NOPB trades bandwidth and offset for micropower operation, while OPA333AIDBVR replaces ultra-low bias current with zero-drift stability - making LMC6081IM/NOPB uniquely balanced for high-Z, medium-speed, single-supply precision sensing.

Availability

LMC6081IM/NOPB is available at Aetrix Electronics and suitable for photodiode preamplification, medical transducer signal conditioning, and precision DAC buffering requiring stable component supply across production lifecycles.

Supply support for LMC6081IM/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 expertise in precision op amps and sensor interface solutions.

The LMC608x family was designed specifically for high-impedance, low-leakage applications including medical instrumentation, analytical chemistry sensors, and scientific measurement systems where femtoampere-level input bias current is mandatory.

FAQ

What is the maximum capacitive load the LMC6081IM/NOPB can drive directly?

The LMC6081IM/NOPB is not characterized for direct capacitive load driving. Stability degrades beyond ~100 pF without external compensation. For loads >100 pF, use a series resistor (≥100 Ω) between output and load, or implement the pull-up resistor method shown in TI's application note SNOS630E Figure 6-3. Verified stable operation with 1 nF loads requires either 500 μA pull-up current or RC feedback compensation per Section 6.1.3.

Does the LMC6081IM/NOPB support true single-supply operation with input signals at ground?

Yes. The LMC6081IM/NOPB features an input common-mode voltage range that includes V–, meaning it accepts input signals at 0 V when V– = 0 V (standard single-supply configuration). This is confirmed in Section 5.7 Electrical Characteristics (VCM to negative rail: V– – 0.1 V min) and enables direct interfacing with grounded sensors like pH electrodes and bridge transducers without level-shifting circuitry.

What is the guaranteed input bias current specification over temperature for LMC6081IM/NOPB?

The LMC6081IM/NOPB guarantees input bias current ≤ ±4 pA over the full operating temperature range of –40°C to +85°C, per Section 5.7 Electrical Characteristics. At 25°C, typical value is 10 fA - three orders of magnitude lower - but design-critical applications must use the worst-case ±4 pA limit for leakage budgeting in high-impedance feedback networks.

Can LMC6081IM/NOPB replace LMC6041 in existing designs?

No. While both are TI precision CMOS op amps, LMC6041 has different pinout (SOIC-8 but nonstandard assignment), lower GBW (0.22 MHz), and no guaranteed rail-to-rail output swing. LMC6081IM/NOPB pin 1, 5, 8 are NC; LMC6041 uses all 8 pins. Direct replacement would require PCB redesign and may compromise bandwidth and output headroom - consult TI's LMC6041 datasheet SNOS122 for comparison.

Is LMC6081IM/NOPB suitable for driving ADC inputs directly?

Yes, when configured as a unity-gain buffer with proper layout. Its rail-to-rail output swing (within 20 mV of rails at 2 kΩ) matches standard SAR and delta-sigma ADC reference ranges, and its 0.8 V/µs slew rate supports settling to 0.1% in <1 µs for 10 V steps. However, guard rings around +IN/–IN and star-grounded V– are mandatory to preserve 10 fA input bias performance and prevent ADC code errors from leakage currents.