Texas Instruments LM4140ACM-1.0/NOPB

Overview

LM4140ACM-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 and battery-powered data acquisition systems.

For engineers reviewing the LM4140ACM-1.0/NOPB datasheet, LM4140ACM-1.0/NOPB pinout, LM4140ACM-1.0/NOPB application, or LM4140ACM-1.0/NOPB equivalent, key selection considerations include its sub-bandgap 1.024 V output, ultra-low 2.2 µV_PP (0.1–10 Hz) noise, EEPROM-trimmed curvature correction, 230 µA operating supply current, and 1 µA shutdown mode - all in an SOIC-8 package.

Technical Context

The LM4140ACM-1.0/NOPB uses a P-channel pass transistor architecture with integrated CMOS DACs and EEPROM registers for factory trimming of both output voltage accuracy and temperature coefficient curvature. Its series topology enables direct connection to load without external resistors, while the enable-controlled internal discharge path actively sinks charge from the output capacitor during shutdown.

It requires a mandatory 1 µF output capacitor for loop stability and transient response, supports load currents up to 8 mA, and maintains regulation with input as low as V_REF + 200 mV over 0°C to 70°C - enabled by its 20 mV typical dropout and 1.8 V minimum operating voltage.

Key Specifications

Pinout & Package

LM4140ACM-1.0/NOPB is housed in an 8-pin SOIC package (4.90 mm × 3.91 mm body size) with exposed pad not electrically connected. Pin functions are validated per TI SNVS053F Rev F datasheet.

Key Features

Applications

Equivalent & Alternatives

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

Compared with REF3012AIDBZR and ADR3410ARJZ-R7, LM4140ACM-1.0/NOPB uniquely delivers 1.024 V with 0.1% accuracy, 3 ppm/°C tempco, and active output discharge - making it optimal for metrology-grade portable instrumentation where bit-perfect scaling and clean power-down behavior are essential.

Availability

LM4140ACM-1.0/NOPB is available at Aetrix Electronics and suitable for portable instrumentation, precision data acquisition, and medical sensor systems requiring stable component supply, long-term calibration integrity, and low-power operation.

Supply support for LM4140ACM-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 company headquartered in Dallas, Texas, designing and manufacturing analog ICs, embedded processors, and system-on-chip solutions for industrial, automotive, and consumer markets.

The LM4140 product line was developed to deliver sub-bandgap precision references with EEPROM-based trimming for applications demanding metrology-grade accuracy without laser calibration - targeting portable test equipment and high-resolution data converters.

FAQ

What is the minimum input voltage required for LM4140ACM-1.0/NOPB to regulate at 1.024 V?

The LM4140ACM-1.0/NOPB requires a minimum input voltage of V_REF + 200 mV over temperature, i.e., 1.224 V, to maintain regulation. At 25°C, dropout is typically 20 mV, allowing operation from 1.044 V - but the 1.224 V specification ensures reliable performance across 0°C to 70°C. This 1.8 V absolute minimum rating provides margin for PCB trace drops and supply ripple.

Does LM4140ACM-1.0/NOPB require an output capacitor, and what type is recommended?

Yes, LM4140ACM-1.0/NOPB requires a 1 µF output capacitor for loop stability and transient response, as specified in the datasheet. Solid tantalum (e.g., Kemet T491A105M010AS) or multilayer ceramic capacitors (e.g., Murata GRM42-6Y5V225Z16) are recommended. The capacitor must meet ESR requirements shown in Figures 22–24; aluminum electrolytics are discouraged below 0°C due to rising ESR.

How does the enable pin function on LM4140ACM-1.0/NOPB, and what happens to the output during shutdown?

The enable pin on LM4140ACM-1.0/NOPB is active-high: driving it ≥0.8×V_IN enables regulation, while pulling it ≤0.4 V disables output. During shutdown, LM4140ACM-1.0/NOPB actively discharges the output capacitor to ground via internal circuitry - ensuring VREF reaches 0 V rapidly and preventing floating reference states that could disrupt downstream circuitry.

Can LM4140ACM-1.0/NOPB drive an ADC reference input directly, and what is its maximum load current?

Yes, LM4140ACM-1.0/NOPB can drive most precision ADC reference inputs directly, as it sources up to 8 mA while maintaining regulation and low noise. For example, it fully supports the reference input of 16-bit SAR ADCs like the ADS8860 (I_REF ≈ 100 µA) and 24-bit delta-sigma converters such as the ADS124S08 (I_REF < 1 mA). Load regulation remains within 20 ppm/mA up to 8 mA.

What is the significance of the "A" grade in LM4140ACM-1.0/NOPB, and how does it differ from B or C grades?

The "A" in LM4140ACM-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% accuracy with 6 ppm/°C tempco, and Grade C offers ±0.1% with 10 ppm/°C. All grades share identical pinout, package, and enable functionality - only the trimmed performance parameters differ.