Texas Instruments LM4140BCM-2.5/NOPB

Overview

LM4140BCM-2.5/NOPB from Texas Instruments is a high-precision, low-noise, low-dropout series voltage reference delivering 2.5 V output with ±0.1% initial accuracy, 3 ppm/°C temperature coefficient (A grade), and 20 mV typical dropout at 1 mA load. It features an enable pin for power management and supports portable instrumentation, precision DACs, and battery-powered data acquisition systems.

For engineers reviewing the LM4140BCM-2.5/NOPB datasheet, LM4140BCM-2.5/NOPB pinout, LM4140BCM-2.5/NOPB application, or LM4140BCM-2.5/NOPB equivalent, key selection considerations include ultra-low 2.2 µV_PP (0.1–10 Hz) noise, 230 µA typical supply current, shutdown current ≤1 µA, and mandatory 1 µF output capacitor for stability.

Technical Context

The LM4140BCM-2.5/NOPB uses EEPROM-trimmed CMOS DACs for curvature-corrected temperature compensation and output voltage trimming-enabling sub-bandgap 2.5 V output with 3 ppm/°C drift over 0°C to 70°C. Its P-channel pass transistor architecture supports operation down to VIN = VREF + 20 mV (typical) at 1 mA.

It operates in two functional modes: normal (EN = VIN) and shutdown (EN = GND), with VREF settling in <200 µs on enable. The device requires external 1 µF output capacitance for loop stability and transient response, with ESR constraints validated for tantalum, ceramic, and aluminum electrolytic types.

Key Specifications

Pinout & Package

LM4140BCM-2.5/NOPB is housed in an 8-pin SOIC package (4.90 mm × 3.91 mm body size) with exposed pad not electrically connected. Ground pins are distributed across four locations (pins 1, 4, 7, 8) to minimize ground impedance and improve PSRR.

Key Features

Applications

Equivalent & Alternatives

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

Compared with REF5025IDR and ADR4525BRZ, LM4140BCM-2.5/NOPB uniquely combines enable functionality, 2.52 V minimum operating voltage, and 0.1% accuracy in SOIC-8 - making it the only option among the three suitable for battery-gauging ICs and energy-harvesting systems with aggressive power cycling.

Availability

LM4140BCM-2.5/NOPB is available at Aetrix Electronics and suitable for portable instrumentation, precision DAC reference design, and battery-powered sensor nodes requiring stable component supply, long-lifecycle support, and TI-qualified traceability.

Supply support for LM4140BCM-2.5/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 and embedded processing chips for industrial, automotive, and consumer markets.

The LM4140 product line delivers high-accuracy, low-noise, low-dropout voltage references optimized for portable, battery-constrained, and precision measurement applications - with EEPROM-based trimming enabling performance previously requiring laser calibration.

FAQ

What is the minimum input voltage required for stable operation of the LM4140BCM-2.5/NOPB?

The LM4140BCM-2.5/NOPB requires a minimum input voltage of VREF + 20 mV (2.52 V) at 1 mA load and 25°C, with 45 mV maximum dropout across 0°C to 70°C. Operation below 2.52 V risks output regulation loss and increased noise. Always verify margin against worst-case dropout (45 mV) and temperature extremes in final design.

Does the LM4140BCM-2.5/NOPB require an output capacitor, and what type is recommended?

Yes - a 1 µF capacitor is mandatory between VREF and GND for loop stability and transient response. TI validates solid tantalum (e.g., Kemet T491A105M010AS), multilayer ceramic (e.g., Murata GRM42-6Y5V225Z16), and aluminum electrolytic types. Ceramic capacitors must meet minimum ESR requirements per Figure 22–24 in the datasheet to prevent oscillation.

How does the enable pin function on the LM4140BCM-2.5/NOPB, and what happens to the output during shutdown?

The LM4140BCM-2.5/NOPB enable pin is active-high: driving EN ≥0.8×VIN turns the device on; pulling EN ≤0.4 V disables it. During shutdown, VREF drops to 0 V within 200 µs, and internal circuitry actively discharges the output capacitor to ground - eliminating hold-up voltage and ensuring clean power sequencing in multi-rail systems.

What is the output noise specification of the LM4140BCM-2.5/NOPB, and how does it scale with output voltage?

The LM4140BCM-2.5/NOPB delivers 2.2 µV_PP (0.1–10 Hz) output noise. Per datasheet Section 6.5 Note 7, noise is linearly proportional to VREF - so the 2.5 V version exhibits 2.2 µV_PP, while the 4.096 V variant would show ~4.4 µV_PP. This scaling enables predictable noise budgeting across the LM4140 family's voltage options.

Can the LM4140BCM-2.5/NOPB drive an ADC reference input directly, and what is its maximum output current capability?

Yes - the LM4140BCM-2.5/NOPB can directly drive most SAR and delta-sigma ADC reference inputs. It sources and sinks up to ±8 mA, with load regulation of 1–20 ppm/mA (2.5 V version). For ADCs drawing >1 mA peak current, ensure the 1 µF output capacitor meets ESR requirements to maintain stability during switching transients.