Texas Instruments LM4140ACMX-1.0/NOPB

Overview

LM4140ACMX-1.0/NOPB from Texas Instruments is a high-precision, low-noise, low-dropout series voltage reference delivering 1.024 V output with ±0.1% initial accuracy, 3 ppm/°C temperature coefficient (A grade), and 20 mV typical dropout at 1 mA. It features an enable pin for power management and operates down to 1.8 V input, making it ideal for precision ADC/DAC biasing in portable instrumentation.

For engineers reviewing the LM4140ACMX-1.0/NOPB datasheet, LM4140ACMX-1.0/NOPB pinout, LM4140ACMX-1.0/NOPB application, or LM4140ACMX-1.0/NOPB equivalent, key selection criteria include ultra-low 2.2 µV_PP (0.1–10 Hz) noise, ≤1 µA shutdown current, 1-µF mandatory output capacitance, and SOIC-8 package compatibility with precision analog signal chains.

Technical Context

The LM4140ACMX-1.0/NOPB uses EEPROM-trimmed CMOS DACs for curvature-corrected temperature compensation and output voltage trimming-enabling sub-bandgap 1.024 V output with 3 ppm/°C drift over 0°C to 70°C. Its P-channel pass transistor architecture supports low dropout and reverse-current protection via inherent body diode.

It operates in two functional modes: normal regulation (EN = VIN) and full shutdown (EN = GND), achieving <200 µs turn-on time and active discharge of the output capacitor during disable. Input voltage range is 1.8 V to 5.5 V, with line regulation as tight as 50 ppm/V (typical) at 25°C.

Key Specifications

Pinout & Package

LM4140ACMX-1.0/NOPB is housed in an 8-pin SOIC package (4.90 mm × 3.91 mm), optimized for automated assembly and thermal performance (R_θJA = 119.3°C/W).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar voltage reference applications.

Compared with REF3012AIDBZR and ADR3410ARJZ-R7, LM4140ACMX-1.0/NOPB uniquely delivers 1.024 V output with 3 ppm/°C drift and 230 µA active current in SOIC-8 - optimizing accuracy, noise, and enable-controlled power cycling for portable precision systems.

Availability

LM4140ACMX-1.0/NOPB is available at Aetrix Electronics and suitable for portable instrumentation, precision data acquisition, battery-powered medical sensors, and automotive cabin monitoring requiring stable component supply across extended production lifecycles.

Supply support for LM4140ACMX-1.0/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 focused on analog and embedded processing technologies, serving industrial, automotive, and personal electronics markets.

The LM4140 product line was engineered to deliver sub-bandgap precision references with EEPROM-based trimming - targeting high-accuracy, low-power applications where traditional bandgap references lack resolution or flexibility.

FAQ

What is the minimum input voltage required for LM4140ACMX-1.0/NOPB to regulate at 1.024 V?

The LM4140ACMX-1.0/NOPB requires a minimum input voltage of 1.8 V, which corresponds to a dropout of 776 mV above its 1.024 V output. At 25°C and 1 mA load, the typical dropout is only 20 mV, meaning VIN ≥ 1.044 V sustains regulation - but the absolute minimum specified operating condition is 1.8 V to guarantee performance across temperature and process variation. This 1.8 V rating makes LM4140ACMX-1.0/NOPB compatible with single-cell Li-ion and Li-polymer battery systems.

Does LM4140ACMX-1.0/NOPB require an output capacitor, and what type is recommended?

Yes, LM4140ACMX-1.0/NOPB mandates a 1-µF output capacitor between VREF and GND for loop stability and transient response. Texas Instruments validates solid tantalum (e.g., Kemet T491A105M010AS) and multilayer ceramic capacitors (e.g., Murata GRM42-6Y5V225Z16) - provided ESR falls within the 0.1–10 Ω range specified in Figures 22–24 of the datasheet. Aluminum electrolytics are discouraged below 0°C due to ESR rise. The capacitor must be placed adjacent to pins 6 (VREF) and 1/4/7/8 (GND) with minimal trace length.

How does the enable function operate on LM4140ACMX-1.0/NOPB, and what happens to the output during shutdown?

The enable pin (pin 3) controls LM4140ACMX-1.0/NOPB's output state: driven high to VIN for normal operation, or pulled to GND to enter shutdown. During shutdown, LM4140ACMX-1.0/NOPB actively discharges the output capacitor through internal circuitry, bringing VREF to 0 V within microseconds. Supply current drops to ≤1 µA, and the device consumes no static power. The enable threshold is V_H = 0.8×V_IN and V_L = 0.4 V, supporting direct interfacing with 1.8-V logic without level shifters.

What is the significance of the "A" grade in LM4140ACMX-1.0/NOPB, and how does it compare to B and C grades?

The "A" in LM4140ACMX-1.0/NOPB denotes the highest accuracy grade: ±0.1% initial output tolerance and 3 ppm/°C maximum temperature coefficient over 0°C to 70°C. Grade B offers ±0.1% initial accuracy but 6 ppm/°C drift; Grade C offers ±0.1% initial accuracy with 10 ppm/°C drift. All grades share identical pinout, package, and electrical characteristics except drift and initial tolerance. The A grade is specified for applications demanding minimal calibration and long-term stability - such as portable test equipment and medical diagnostics where field recalibration is impractical.

Can LM4140ACMX-1.0/NOPB be used to drive an ADC reference input directly, and what is its maximum output current capability?

Yes, LM4140ACMX-1.0/NOPB can directly drive most SAR and delta-sigma ADC reference inputs. Its output is specified to source and sink up to ±8 mA while maintaining regulation and noise performance. Typical ADC reference inputs draw <100 µA average current, well within this limit. For high-speed ADCs with large dynamic current demands (e.g., >1 mA peak), TI recommends adding a local 1-µF bypass capacitor at the ADC REF pin. The LM4140ACMX-1.0/NOPB's 2.2 µV_PP noise and 3 ppm/°C drift ensure ENOB preservation without external buffering in most 16-bit systems.