Texas Instruments LMC660AIMX

Overview

LMC660AIMX from Texas Instruments is a quad CMOS operational amplifier optimized for precision, low-leakage, single-supply operation. It delivers rail-to-rail output swing (e.g., 14.63 V at VS = 15 V, RL = 2 kΩ), ultra-low input bias current (2 fA typ.), and high open-loop gain (2000 V/mV into 2 kΩ) - enabling high-impedance sensor buffering and precision current-to-voltage conversion in medical instrumentation and industrial controls.

For engineers reviewing the LMC660AIMX datasheet, LMC660AIMX pinout, LMC660AIMX application, or LMC660AIMX equivalent, this page provides verified specifications, SOIC-14 package details, real-world design implications of its 1.1 V/µs slew rate and 1.4 MHz GBW, and validated alternative options for quad-channel precision op amp selection.

Technical Context

The LMC660AIMX employs a proprietary CMOS front-end topology with differential input stage and rail-to-rail output stage, supporting full input common-mode range down to V− and output swing within 0.35 V of rails under 2 kΩ load. Its ultra-low input bias current (2 fA typ.) stems from guarded input structures and advanced oxide processing, making it suitable for picoampere-level signal conditioning.

It operates across 4.75 V to 15.5 V single supply (or ±2.375 V to ±7.75 V dual supply), with quiescent current per amplifier fixed at 375–550 µA independent of V+, and features 130 dB crosstalk between channels - critical for multi-channel instrumentation where inter-channel coupling must be minimized.

Key Specifications

Pinout & Package

LMC660AIMX is housed in a 14-pin SOIC (D package), 3.90 mm × 8.65 mm body, 1.27 mm pitch, with exposed pad not present. Pin functions are electrically validated per TI SNOSC51D Rev FEBRUARY 2024.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLV2474IDR and OPA4188AIPW, LMC660AIMX uniquely balances femtoampere input bias, rail-to-rail output, and SOIC-14 compatibility - making it optimal for space-constrained, high-impedance, single-supply systems where zero-drift isn't required but leakage must be minimized.

Availability

LMC660AIMX is available at Aetrix Electronics and suitable for medical instrumentation, industrial sensor signal conditioning, and automotive cabin sensors requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for LMC660AIMX 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 heritage in precision op amp design and manufacturing excellence.

The LMC660AIMX belongs to TI's LMC66x family of CMOS rail-to-rail op amps, engineered specifically for ultra-low-input-bias, single-supply precision applications in medical, industrial, and automotive systems where leakage and drift compromise measurement integrity.

FAQ

What is the maximum capacitive load the LMC660AIMX can drive stably?

The LMC660AIMX becomes unstable with purely capacitive loads above ~100 pF in unity-gain follower configuration. For loads >50 pF, TI recommends adding a 50–100 Ω series resistor at the output and a 5–10 pF feedback capacitor from output to inverting input. This compensation restores phase margin without degrading low-frequency gain. The LMC660AIMX datasheet Figure 6-3 and Section 6.1.3 detail this method. Always verify stability on the final PCB layout, as stray capacitance affects threshold.

Does the LMC660AIMX support true rail-to-rail input common-mode range?

Yes - the LMC660AIMX input common-mode range extends from V− to (V+) – 1.9 V at 15 V supply, and includes V− (ground in single-supply use). This allows direct interfacing with sensors whose output swings to ground, such as thermocouples or resistive bridges referenced to system ground. However, input bias current increases near the positive rail, so designs requiring lowest IB should keep VCM below (V+) – 2 V.

How does the LMC660AIMX compare to the LM358 in pin compatibility and performance?

The LMC660AIMX is not pin-compatible with the LM358 - the LM358 is a dual op amp in SOIC-8, while LMC660AIMX is quad in SOIC-14. However, TI states the LMC662 (dual version) is pin-for-pin compatible with LM358. LMC660AIMX offers superior specs: 2 fA vs. 45 nA input bias, 1.4 MHz GBW vs. 1 MHz, and rail-to-rail output vs. ~1.5 V headroom - enabling higher-precision, lower-power, single-supply upgrades where board real estate allows SOIC-14.

What is the recommended bypassing strategy for LMC660AIMX in a 4-channel layout?

Each LMC660AIMX requires at least one 0.1 µF X7R ceramic capacitor placed within 5 mm of Pins 4 (V+) and 11 (V–), with short, low-inductance traces to ground. For multi-channel boards, separate 0.1 µF caps per amplifier pair are preferred. Avoid shared vias - use dedicated ground planes under the SOIC-14 footprint. TI's Layout Guidelines (Section 6.3.1) emphasize guard rings around all input traces to suppress surface leakage, especially critical given the 2 fA bias specification.

Can LMC660AIMX operate from a 3.3 V supply?

No - the LMC660AIMX minimum specified supply voltage is 4.75 V (single supply) per Section 5.3 Recommended Operating Conditions. Operation below 4.75 V is outside guaranteed specifications and may result in degraded rail-to-rail output swing, reduced open-loop gain, or increased input offset voltage. For 3.3 V systems, consider TI's TLV2464 or OPA4340, which are characterized down to 2.7 V and retain rail-to-rail I/O.