Texas Instruments LMC6081AIM

Overview

LMC6081AIM from Texas Instruments is a precision single-channel CMOS operational amplifier optimized for ultra-low-input-bias-current, rail-to-rail output swing, and single-supply operation from 4.5V to 15.5V. It delivers 150μV typical input offset voltage, 10fA typical input bias current, and 123dB open-loop gain into 2kΩ - enabling high-accuracy signal conditioning in photodiode preamplifiers, medical instrumentation, and charge amplifiers for piezoelectric transducers.

For engineers reviewing the LMC6081AIM datasheet, LMC6081AIM pinout, LMC6081AIM application, or LMC6081AIM equivalent, key selection considerations include its guaranteed 10fA input bias current at 25°C, rail-swing capability within 20mV of supply rails under 2kΩ load, input common-mode range extending to V–, and SOIC-8 package compatibility with precision analog PCB layout requirements including guard-ring implementation.

Technical Context

The LMC6081AIM employs a proprietary CMOS input stage with gate-oxide isolation to achieve sub-picoampere input bias current, making it suitable for high-impedance sensor interfaces where leakage dominates error budgets. Its rail-to-rail output stage uses complementary MOSFETs to deliver full dynamic range across the supply, while internal compensation ensures stability with capacitive loads up to 100pF when used with recommended pull-up resistors.

Unlike conventional op amps, the LMC6081AIM maintains >60dB CMRR over 0V to (V+)–1.9V common-mode range and exhibits <1μV/°C offset drift - critical for DC-coupled transducer amplification in unregulated battery-powered systems operating from –40°C to +85°C.

Key Specifications

Pinout & Package

LMC6081AIM is housed in an 8-pin SOIC (D package) with exposed pad thermal enhancement per TI's mechanical drawing SLMA007. Pin 1 and pins 5–8 are no-connect (NC) terminals internally unconnected and may be left floating or tied to ground for EMI suppression.

Key Features

Applications

Equivalent & Alternatives

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

Compared with OPA376AIDBVR and LTC1050CS8#PBF, the LMC6081AIM uniquely balances femtoampere input bias current, rail-to-rail output, and single-supply operation - making it irreplaceable in high-impedance, low-power, DC-coupled sensor interfaces where both leakage and supply constraints dominate design.

Availability

LMC6081AIM is available at Aetrix Electronics and suitable for medical instrumentation, photodiode preamplification, and piezoelectric charge amplification requiring stable component supply across extended production lifecycles.

Supply support for LMC6081AIM 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 over 50 years of innovation in precision analog ICs.

The LMC6081AIM belongs to TI's LMC608x family of precision CMOS op amps, designed specifically for ultra-low-input-bias-current applications including sensor signal conditioning, medical diagnostics, and scientific instrumentation where femtoampere-level leakage must be avoided.

FAQ

What is the maximum supply voltage for the LMC6081AIM?

The LMC6081AIM supports a maximum single-supply voltage of 15.5 V and dual-supply operation up to ±7.75 V. Exceeding 15.5 V risks permanent damage per absolute maximum ratings. For reliable long-term operation, TI recommends limiting V+ to ≤13 V when sinking output current to avoid reliability degradation cited in Section 5.1 Note (3) of the datasheet. The LMC6081AIM must always operate within these bounds to maintain its specified 10 fA input bias current and rail-to-rail output performance.

Does the LMC6081AIM support rail-to-rail input common-mode range?

No, the LMC6081AIM does not support rail-to-rail input common-mode range. Its input common-mode voltage extends to V– (ground) but only up to (V+) – 1.9 V at 25°C - meaning it cannot accept signals within 1.9 V of the positive rail. This limitation is explicitly defined in Table 5-7 under "INPUT VOLTAGE" for VCM range. The LMC6081AIM's strength lies in its rail-to-rail *output* swing and inclusion of V– in the input range, not full rail-to-rail input. Designers must ensure input signals remain ≥1.9 V below V+ to maintain CMRR >60 dB.

Can the LMC6081AIM drive capacitive loads directly?

The LMC6081AIM can drive small capacitive loads (<50 pF) directly, but larger loads require external compensation. As detailed in Section 6.1.3, direct capacitive loading degrades phase margin and causes oscillation due to pole formation between output impedance and load capacitance. TI recommends adding a 10 kΩ pull-up resistor to V+ for loads >100 pF or using the RC network shown in Figure 6-2 (R1/C1) to feed high-frequency components back to the inverting input. These techniques preserve stability while maintaining the LMC6081AIM's 1.3 MHz GBW and 0.8 V/μs slew rate in precision timing circuits.

What is the guaranteed input offset voltage specification for LMC6081AIM over temperature?

The LMC6081AIM guarantees a maximum input offset voltage of ±800 μV over the full operating temperature range of –40°C to +85°C, as specified in Table 5-7 under "OFFSET VOLTAGE" for the LMC608xAI grade. At 25°C, the typical value is ±150 μV with a maximum of ±350 μV. The device also exhibits low drift of ≤1 μV/°C, meaning offset change across the full temperature range contributes ≤125 μV - well within the ±800 μV limit. This performance makes the LMC6081AIM suitable for applications like medical instrumentation where calibration stability is essential.

Is the LMC6081AIM pin-compatible with other members of the LMC608x family?

No, the LMC6081AIM is not pin-compatible with the LMC6082 or LMC6084. While all three share the same SOIC-8 package footprint, the LMC6081AIM is a single-channel amplifier with dedicated +IN (Pin 3), –IN (Pin 2), OUT (Pin 6), V+ (Pin 7), and V– (Pin 4); Pins 1, 5, and 8 are NC. In contrast, the LMC6082 dual op amp uses Pins 1 and 7 for OUT A/B and Pins 2/3/5/6 for its four inputs - making direct substitution impossible without PCB redesign. The LMC6081AIM's unique pinout is optimized for single-amplifier layouts requiring minimal routing complexity and guard-ring isolation.