Texas Instruments LM4140BCMX-2.5

Overview

LM4140BCMX-2.5 from Texas Instruments is a high-precision, low-noise, low-dropout series voltage reference delivering 2.5 V output with ±0.1% initial accuracy, 10 ppm/°C temperature coefficient (C grade), and 20 mV typical dropout at 1 mA load. It features an enable pin for power management and operates down to 1.8 V input, making it suitable for battery-powered precision ADCs and portable instrumentation.

For engineers reviewing the LM4140BCMX-2.5 datasheet, LM4140BCMX-2.5 pinout, LM4140BCMX-2.5 application, or LM4140BCMX-2.5 equivalent, key selection considerations include its ultra-low 2.2 µV_PP (0.1–10 Hz) noise, 230 µA typical supply current, 1 µF required output capacitor, shutdown current ≤1 µA, and SOIC-8 package compatibility with space-constrained analog signal chains.

Technical Context

The LM4140BCMX-2.5 uses EEPROM-trimmed CMOS DACs for curvature-corrected temperature compensation and output voltage trimming-enabling higher resolution than conventional bandgap references. Its P-channel pass transistor architecture supports operation with VIN as low as VREF + 200 mV over temperature.

It integrates an active output discharge path during disable mode, restoring VREF in <200 µs on enable. The device requires a 1-µF output capacitor for loop stability and transient response, with ESR constraints validated for tantalum, ceramic, and aluminum electrolytic types per TI application guidance.

Key Specifications

Pinout & Package

LM4140BCMX-2.5 is housed in an 8-pin SOIC package (4.90 mm × 3.91 mm body size) with exposed pad not present. 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 REF3025AIDBZR and ADR3425ARJZ-R7, the LM4140BCMX-2.5 uniquely combines 0.1% accuracy, 10 ppm/°C tempco, 2.2 µV_PP noise, and 8 mA drive in SOIC-8 - making it optimal for high-fidelity, enable-controlled, medium-current reference roles where thermal stability and noise dominate design trade-offs.

Availability

LM4140BCMX-2.5 is available at Aetrix Electronics and suitable for portable instrumentation, industrial process control, medical diagnostics, and automotive battery monitoring requiring stable component supply, long-lifecycle support, and guaranteed traceability.

Supply support for LM4140BCMX-2.5 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 communications markets with high-reliability components.

The LM4140 family was designed specifically for high-accuracy, low-noise, low-dropout voltage reference applications in portable and precision measurement systems - emphasizing factory-trimmed stability and enable-controlled power efficiency.

FAQ

What is the recommended output capacitor for LM4140BCMX-2.5 and why is it required?

The LM4140BCMX-2.5 requires a 1 µF capacitor between VREF and GND for loop stability and transient response. This capacitor compensates the internal control loop and supplies instantaneous current during load steps. TI validates performance with solid tantalum (e.g., Kemet T491A105M010AS) and ceramic types meeting minimum ESR requirements - omitting it risks oscillation or overshoot in precision ADC applications.

Does LM4140BCMX-2.5 support shutdown mode, and how is it controlled?

Yes, LM4140BCMX-2.5 supports shutdown mode via its active-high EN pin (Pin 3). Driving EN to GND reduces supply current to ≤1 µA and discharges the output capacitor internally. To enable, tie EN to VIN - never leave it floating. The logic thresholds are VL ≤ 0.4 V (low) and VH ≥ 0.8×VIN (high), ensuring compatibility with 1.8 V to 5 V controllers.

What is the maximum load current LM4140BCMX-2.5 can drive while maintaining 2.5 V accuracy?

The LM4140BCMX-2.5 is specified to source or sink up to 8 mA while maintaining output voltage accuracy within ±0.5% of nominal 2.5 V. At 8 mA load, dropout rises to 235 mV (max) over temperature. For higher currents, TI recommends external boost circuits - e.g., using a PNP transistor as shown in Figure 30 of the LM4140 datasheet - to preserve reference integrity.

How does the temperature coefficient of LM4140BCMX-2.5 impact system accuracy over 0°C to 70°C?

The LM4140BCMX-2.5 (C grade) has a guaranteed 10 ppm/°C temperature coefficient over 0°C to 70°C. Across this 70°C span, maximum drift is 700 ppm (0.07%), or ±1.75 mV from 2.5 V. Combined with ±2.5 mV initial error (0.1%), total worst-case deviation is ±4.25 mV - sufficient for 12-bit systems (LSB = 610 µV at 2.5 V) without calibration.

Can LM4140BCMX-2.5 be used with ceramic output capacitors, and what ESR considerations apply?

Yes, LM4140BCMX-2.5 supports multilayer ceramic capacitors (MLCCs), but ESR must be ≥0.1 Ω (per Figure 23 in SNVS053F) to ensure stability. MLCCs often exhibit very low ESR (<0.01 Ω); therefore, TI recommends verifying manufacturer datasheets and testing with ≥0.2 µF values. Verified examples include Murata GRM42-6Y5V225Z16 (2.2 µF) - avoiding ultralow-ESR types unless series resistance is added.