Texas Instruments LMC6494AEMX/NOPB

Overview

LMC6494AEMX/NOPB from Texas Instruments (formerly National Semiconductor) is a quad CMOS rail-to-rail input and output operational amplifier designed for single-supply automotive sensor signal conditioning. It operates from 5V to 15V, delivers rail-to-rail output swing within 20 mV of supply rails at 100 kΩ load, features ultra-low 150 fA input bias current, and supports −40°C to +125°C junction temperature - enabling direct interfacing with high-impedance pressure, oxygen, and temperature sensors in engine control units.

For engineers reviewing the LMC6494AEMX/NOPB datasheet, LMC6494AEMX/NOPB pinout, LMC6494AEMX/NOPB application, or LMC6494AEMX/NOPB equivalent, key selection criteria include guaranteed rail-to-rail input common-mode range beyond supply rails, 82 dB CMRR at 0–15 V input voltage, 1.3 V/µs slew rate, 1.5 MHz gain-bandwidth product, and SOIC-14 packaging for space-constrained automotive PCB layouts.

Technical Context

The LMC6494AEMX/NOPB employs a proprietary CMOS input stage enabling true rail-to-rail input operation - accepting signals up to 0.3 V beyond V− and V+ - eliminating phase inversion and non-linear errors when transducer outputs exceed supply limits. Its output stage delivers symmetrical sourcing/sinking capability with 110 Ω sourcing and 80 Ω sinking impedance at 5 V supply.

It achieves 120 dB open-loop gain and 82 dB CMRR across full common-mode range (0 V to 15 V at V+ = 15 V), ensuring accuracy in non-inverting configurations used in precision sensor front-ends. The device maintains stable operation with capacitive loads when paired with appropriate resistive parallel termination, as validated in TI's application curves.

Key Specifications

Pinout & Package

LMC6494AEMX/NOPB is housed in a 14-pin SOIC (Small Outline Integrated Circuit) package (TI package code M14A), 3.9 mm wide, with standard 1.27 mm pitch. This surface-mount package supports automated assembly and thermal performance of θJA = 118 °C/W on 2-layer PCBs.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLV2474IDR and OPA4340UA, LMC6494AEMX/NOPB uniquely combines extended temperature operation, rail-to-rail input beyond supplies, and 150 fA input bias - making it the only qualified option for high-reliability automotive sensor front-ends requiring simultaneous wide VCM, low IB, and AEC-Q100 alignment.

Availability

LMC6494AEMX/NOPB is available at Aetrix Electronics and suitable for automotive engine control units, battery management systems, and industrial pressure monitoring requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for LMC6494AEMX/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 acquired National Semiconductor in 2011 and maintains full technical and manufacturing continuity for legacy precision analog products including the LMC649x family.

The LMC6494AEMX/NOPB belongs to TI's high-reliability automotive op-amp portfolio, engineered specifically for sensor signal conditioning in harsh-temperature environments where rail-to-rail input margin and ultra-low input current are mandatory.

FAQ

What is the maximum operating temperature range for LMC6494AEMX/NOPB?

The LMC6494AEMX/NOPB is specified for junction temperatures from −40°C to +125°C, matching AEC-Q100 Grade 1 automotive requirements. This range is validated across all electrical parameters in the official datasheet (DS012049, page 3), and applies to the SOIC-14 package variant shipped in tape-and-reel format as LMC6494AEMX/NOPB.

Does LMC6494AEMX/NOPB support true rail-to-rail input beyond the supply rails?

Yes. The LMC6494AEMX/NOPB guarantees an input common-mode voltage range from V− − 0.25 V to V+ + 0.25 V at V+ = 15 V (DS012049, page 2), enabling direct interface with transducers whose outputs exceed supply limits - a key differentiator versus standard rail-to-rail op-amps that clamp at the rails.

What is the typical input bias current of LMC6494AEMX/NOPB, and why does it matter?

The typical input bias current of LMC6494AEMX/NOPB is 150 fA (0.15 fA), with a maximum of 200 pA across temperature. This ultra-low value prevents loading errors in high-impedance sensor circuits - such as piezoresistive bridges or thermopiles - where even nanoamp-level currents would introduce unacceptable offset and gain errors.

Can LMC6494AEMX/NOPB drive capacitive loads directly?

LMC6494AEMX/NOPB is not optimized for direct capacitive load driving. As noted in the Application Hints (DS012049, page 13), capacitive loads reduce phase margin and may cause oscillation. Stable operation requires either a series resistor between output and load or a parallel RC network, as demonstrated in Figure 5 of the datasheet.

Is LMC6494AEMX/NOPB pin-compatible with other LMC6494 variants?

Yes. LMC6494AEMX/NOPB shares identical pinout and footprint with LMC6494AEM, LMC6494BEM, and LMC6494BEMX - all use the SOIC-14 (M14A) package. The 'A' grade denotes tighter input offset voltage (3.0 mV max vs. 6.0 mV for 'B'), while 'MX' indicates tape-and-reel packaging; electrical and mechanical compatibility is fully maintained.