Texas Instruments LM4140BCMX-1.2/NOPB

Overview

LM4140BCMX-1.2/NOPB from Texas Instruments is a high-precision, low-noise, low-dropout series voltage reference delivering 1.25 V output with ±0.1% initial accuracy, 3 ppm/°C temperature coefficient (A grade), 20 mV typical dropout at 1 mA, and 230 µA typical supply current. It features an enable pin for power management and is designed for precision analog signal chains in portable instrumentation and data acquisition systems.

For engineers reviewing the LM4140BCMX-1.2/NOPB datasheet, LM4140BCMX-1.2/NOPB pinout, LM4140BCMX-1.2/NOPB application, or LM4140BCMX-1.2/NOPB equivalent, key selection criteria include initial accuracy, thermal drift, dropout voltage under load, noise performance (2.2 µV_PP, 0.1–10 Hz), and enable-controlled shutdown capability consuming ≤1 µA.

Technical Context

The LM4140BCMX-1.2/NOPB employs EEPROM-trimmed CMOS DACs for curvature-corrected temperature compensation and output voltage trimming-enabling sub-bandgap 1.25 V output with 3 ppm/°C stability over 0°C to 70°C. Its P-channel pass transistor architecture supports operation down to VIN = VREF + 20 mV (typical) while maintaining regulation.

It integrates internal charge-discharge circuitry on the enable pin to rapidly disable VREF and sink the output capacitor during shutdown (<200 µs turn-on). The device requires a mandatory 1 µF output capacitor for loop stability and transient response, with ESR constraints validated across tantalum, ceramic, and aluminum electrolytic types.

Key Specifications

Pinout & Package

LM4140BCMX-1.2/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 precision voltage reference applications.

Compared with REF3012AIDBZR and ADR3412ARJZ-R7, the LM4140BCMX-1.2/NOPB uniquely delivers 3 ppm/°C stability with enable control and 8 mA drive in a cost-optimized SOIC package-making it optimal for battery-powered precision instruments where accuracy, power gating, and load capability are jointly constrained.

Availability

LM4140BCMX-1.2/NOPB is available at Aetrix Electronics and suitable for portable instrumentation, data acquisition systems, and battery-powered medical devices requiring stable component supply with guaranteed long-term availability.

Supply support for LM4140BCMX-1.2/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, EEPROM-trimmed voltage references for portable, battery-sensitive applications demanding high initial accuracy and ultra-low thermal drift-targeting instrumentation, medical, and industrial measurement markets.

FAQ

What is the maximum load current supported by the LM4140BCMX-1.2/NOPB?

The LM4140BCMX-1.2/NOPB is specified to source up to 8 mA while maintaining output accuracy within datasheet limits. At 8 mA load, dropout voltage rises to 235 mV (max) over temperature, and load regulation degrades to 150 ppm/mA. For reliable operation beyond 5 mA, verify thermal rise and PCB layout per TI's recommended copper pour guidelines.

Does the LM4140BCMX-1.2/NOPB require an output capacitor, and why?

Yes-the LM4140BCMX-1.2/NOPB requires a minimum 1 µF output capacitor connected between VREF and GND for loop stability and transient response. Without it, the device may oscillate or exhibit poor load step recovery. TI validates stability with solid tantalum, ceramic, and aluminum electrolytic types meeting specified ESR ranges, as detailed in Figures 22–24 of the SNVS053F datasheet.

How does the enable pin function on the LM4140BCMX-1.2/NOPB?

The enable pin (Pin 3) controls device power state: driven to VIN (logic high) for normal operation; pulled to GND (logic low) to disable output and reduce supply current to ≤1 µA. During disable, internal circuitry actively discharges the output capacitor to GND. The pin must never be left floating and requires valid logic thresholds (V_H ≥ 0.8×VIN, V_L ≤ 0.4 V) per Electrical Characteristics table.

What is the significance of the 'B' and 'C' in LM4140BCMX-1.2/NOPB?

The 'B' denotes the temperature coefficient grade (6 ppm/°C max), and the 'C' indicates the initial accuracy grade (±0.1%). The full designation LM4140BCMX-1.2/NOPB confirms it is the 1.25 V version, SOIC-8 package (MX), commercial temperature range (0°C to 70°C), and lead-free/nickel-palladium-gold finish (NOPB). This differs from the 'A' grade (3 ppm/°C) and 'C' grade (10 ppm/°C) variants.

Can the LM4140BCMX-1.2/NOPB be used with a 1.8 V supply?

Yes-the LM4140BCMX-1.2/NOPB is explicitly rated for operation down to 1.8 V input (VIN ≥ VREF + 400 mV over temperature), making it compatible with single-cell Li-ion, LiFePO₄, and regulated 1.8 V rails. At 1.8 V, dropout margin is 550 mV, ensuring robust regulation even with line transients or PCB trace resistance.