Texas Instruments LM4140BCM-4.1

Overview

LM4140BCM-4.1 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 20 mV typical dropout at 1 mA - designed for precision ADC/DAC biasing in portable instrumentation and battery-powered systems.

For engineers reviewing the LM4140BCM-4.1 datasheet, LM4140BCM-4.1 pinout, LM4140BCM-4.1 application, or LM4140BCM-4.1 equivalent, key selection considerations include enable-controlled shutdown (≤1 µA), ultra-low 2.2 µV_PP (0.1–10 Hz) noise, 1.8 V minimum operating voltage, and SOIC-8 package compatibility with standard PCB layouts for metrology-grade signal chains.

Technical Context

The LM4140BCM-4.1 employs 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 supports operation down to VIN = VREF + 20 mV (typical) while maintaining regulation under 1–8 mA load.

Enable functionality provides fast turn-on (<200 µs) and active discharge of the output capacitor during shutdown. The device requires a mandatory 1 µF output capacitor for loop stability and transient response, with ESR constraints validated for tantalum, ceramic, and aluminum electrolytic types per TI's application guidance.

Key Specifications

Pinout & Package

LM4140BCM-4.1 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 internally bonded to minimize thermal resistance and improve PSRR.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM4140BCM-4.1, REF5040IDR trades 4× higher supply current for marginal noise reduction, while ADR4540BRZ achieves tighter specs but forfeits enable control and low-voltage operation - making LM4140BCM-4.1 the optimal balance for portable, battery-gated precision systems.

Availability

LM4140BCM-4.1 is available at Aetrix Electronics and suitable for portable instrumentation, precision data acquisition, battery-powered medical sensors, and automotive diagnostic tools requiring stable component supply with guaranteed long-term continuity.

Supply support for LM4140BCM-4.1 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, embedded processing, and connectivity technologies, with decades of leadership in precision analog ICs.

The LM4140 product line was engineered specifically for high-accuracy, low-power, low-voltage reference needs in portable and industrial measurement systems - emphasizing trimmable tempco, enable-controlled power gating, and robust output drive.

FAQ

What is the minimum input voltage required for stable operation of the LM4140BCM-4.1?

The LM4140BCM-4.1 requires VIN ≥ VREF + 20 mV (typical) for regulation, meaning a minimum of 4.116 V at 25°C and 1 mA load. Over temperature (0°C–70°C), dropout rises to 45 mV max, so 4.141 V is recommended for guaranteed operation across the full range. This enables compatibility with regulated 4.2 V supplies common in Li-ion battery systems.

Does the LM4140BCM-4.1 require an output capacitor, and what type is recommended?

Yes - a 1 µF output capacitor is mandatory 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, provided ESR falls within specified ranges. Ceramic capacitors require ≥0.2 µF due to ESR limitations, and must be selected per manufacturer's temperature-coefficient derating curves.

How does the enable pin function on the LM4140BCM-4.1, and what happens to the output during shutdown?

The LM4140BCM-4.1 enable pin is active-high: driving it ≥0.8×VIN enables the reference, while pulling it ≤0.4 V disables it. During shutdown, the output is actively discharged to GND via internal circuitry - preventing residual voltage hold-up that could interfere with system power sequencing or cause latch-up in downstream circuitry.

What is the output noise performance of the LM4140BCM-4.1, and how does it scale with output voltage?

The LM4140BCM-4.1 delivers 2.2 µV_PP (0.1–10 Hz) noise for the 4.096 V version. Per datasheet Section 6.5 Note (7), output noise is linearly proportional to VREF - so a 2.048 V variant would exhibit ~1.1 µV_PP. This low 1/f noise preserves dynamic range in high-resolution ADCs without requiring external filtering, reducing BOM count and board area.

Can the LM4140BCM-4.1 drive an ADC reference input directly, and what is its maximum load current?

Yes - the LM4140BCM-4.1 can directly drive most precision ADC reference inputs. It sources and sinks up to ±8 mA while maintaining regulation and specified accuracy. For example, it fully supports the AD768x family (up to 500 µA dynamic current) and ADS12xx delta-sigma converters (typically <100 µA), eliminating the need for external buffer amplifiers in most implementations.