Texas Instruments LM4140ACM-4.1/NOPB

Overview

LM4140ACM-4.1/NOPB from Texas Instruments is a high-precision, low-noise, low-dropout series voltage reference delivering 4.096 V output with ±0.1% initial accuracy, 3 ppm/°C temperature coefficient (A grade), and 2.2 µV_PP (0.1–10 Hz) output noise. It operates from as low as 1.8 V input, supports up to 8 mA load, and features an enable pin for power management - ideal for precision ADC/DAC biasing in portable instrumentation.

For engineers reviewing the LM4140ACM-4.1/NOPB datasheet, LM4140ACM-4.1/NOPB pinout, LM4140ACM-4.1/NOPB application, or LM4140ACM-4.1/NOPB equivalent, key selection considerations include dropout voltage at 1 mA (20 mV typ), shutdown current (≤1 µA), required 1-µF output capacitor stability, and SOIC-8 package compatibility with precision analog PCB layouts.

Technical Context

The LM4140ACM-4.1/NOPB uses EEPROM-trimmed CMOS DACs for curvature-corrected temperature compensation and output voltage trimming - enabling sub-bandgap 4.096 V output with 3 ppm/°C drift over 0°C to 70°C. Its P-channel pass transistor architecture delivers low dropout and reverse-current protection via inherent VIN–VREF diode.

It operates in two functional modes: enabled (V_EN ≥ 0.8×V_IN) with 230 µA supply current and disabled (V_EN < 0.4 V) with ≤1 µA quiescent current. Output stability requires a 1-µF capacitor with ESR within 0.1–10 Ω, verified with solid tantalum and selected ceramic types.

Key Specifications

Pinout & Package

LM4140ACM-4.1/NOPB is housed in an 8-pin SOIC package (4.90 mm × 3.91 mm body size) with exposed pad not electrically connected. Pin 5 is NC (no connect); pins 1, 4, 7, and 8 are ground terminals for low-impedance return path and thermal dissipation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM4140ACM-4.1/NOPB, REF5040IDR trades 5× higher supply current for 0.05% accuracy, while ADR4540BRZ offers lower noise and tempco in a physically larger SOIC-8 - making LM4140ACM-4.1/NOPB optimal for space-constrained, battery-powered precision systems requiring balanced performance.

Availability

LM4140ACM-4.1/NOPB is available at Aetrix Electronics and suitable for portable instrumentation, industrial process control, and medical equipment requiring stable component supply with guaranteed long-term availability and traceable lot documentation.

Supply support for LM4140ACM-4.1/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 leadership in precision reference design and manufacturing.

The LM4140 product line was engineered to deliver sub-bandgap reference voltages with EEPROM-based trimming - targeting high-accuracy, low-power applications in portable test equipment and industrial sensors.

FAQ

What is the minimum input voltage required for stable operation of the LM4140ACM-4.1/NOPB?

The LM4140ACM-4.1/NOPB requires a minimum input voltage of V_REF + 20 mV (4.116 V) at 1 mA load to maintain regulation within specification. At higher loads or elevated temperatures, the dropout voltage increases - up to 45 mV over 0°C–70°C - so a 4.15 V minimum supply is recommended for robust margin. This low dropout enables direct use with single-cell Li-ion batteries.

Does the LM4140ACM-4.1/NOPB require an output capacitor, and if so, what type and value?

Yes, the LM4140ACM-4.1/NOPB requires a 1-µF output capacitor for loop stability and transient response. TI specifies ESR between 0.1 Ω and 10 Ω; verified types include Kemet T491A105M010AS (tantalum) and Murata GRM42-6Y5V225Z16 (ceramic). Using no capacitor or one outside this ESR range risks oscillation or overshoot during load steps.

How does the enable pin function on the LM4140ACM-4.1/NOPB, and what happens during shutdown?

The LM4140ACM-4.1/NOPB enable pin (Pin 3) turns the reference on when pulled ≥0.8×V_IN, and off when <0.4 V. During shutdown, V_REF drops to 0 V within 200 µs, and supply current falls to ≤1 µA. Internal circuitry actively discharges the output capacitor to ground - preventing residual voltage that could bias downstream circuitry.

Can the LM4140ACM-4.1/NOPB drive an ADC reference input directly, and what is its maximum load current?

Yes, the LM4140ACM-4.1/NOPB can directly drive most ADC reference inputs, with a guaranteed output drive capability of ±8 mA. For typical 16–24-bit SAR or delta-sigma ADCs drawing <100 µA average current, this provides ample margin. However, pulsed reference currents (e.g., successive-approximation charging) require careful decoupling - TI recommends a 100 nF ceramic capacitor placed adjacent to the ADC REF pin.

What is the long-term stability specification for the LM4140ACM-4.1/NOPB, and how is it measured?

The LM4140ACM-4.1/NOPB exhibits 60 ppm maximum long-term stability after 1000 hours of operation at 25°C - defined as the change in output voltage under constant load and temperature. This metric reflects aging of the trimmed bandgap core and EEPROM calibration data retention, and is validated across production lots using Statistical Quality Control methods per TI's datasheet testing protocol.