Texas Instruments LM4140CCMX-1.2/NOPB

Overview

LM4140CCMX-1.2/NOPB from Texas Instruments is a high-precision, low-noise, low-dropout series voltage reference with 1.25 V nominal output, 0.1% initial accuracy, 3 ppm/°C temperature coefficient (C grade), 20 mV typical dropout at 1 mA, and enable-controlled shutdown consuming ≤1 µA. It serves as a stable reference in precision ADCs, DACs, and portable instrumentation where low supply voltage (as low as 1.8 V) and ultra-low noise (2.2 µV_PP, 0.1–10 Hz) are critical.

For engineers reviewing the LM4140CCMX-1.2/NOPB datasheet, LM4140CCMX-1.2/NOPB pinout, LM4140CCMX-1.2/NOPB application, or LM4140CCMX-1.2/NOPB equivalent, key selection considerations include its EEPROM-trimmed curvature correction for superior TC stability, 1-µF mandatory output capacitor requirement, enable pin logic thresholds (V_H = 0.8×V_IN, V_L = 0.4 V), and SOIC-8 package compatibility with standard PCB assembly processes.

Technical Context

The LM4140CCMX-1.2/NOPB uses a P-channel pass transistor with integrated EEPROM and CMOS DACs for factory trimming of both initial accuracy and temperature coefficient curvature-enabling 3 ppm/°C performance without external compensation. Its series architecture supports operation down to V_IN = V_REF + 20 mV (typical) and delivers up to 8 mA output current while maintaining regulation.

Functional modes are strictly binary: EN tied to V_IN enables normal operation with 230 µA typical supply current; EN pulled to GND forces shutdown with ≤1 µA quiescent current and active discharge of the output capacitor. The device requires no input capacitor but mandates a 1-µF output capacitor (±20% tolerance, ESR 0.1–10 Ω) for loop stability across 0°C to 70°C.

Key Specifications

Pinout & Package

LM4140CCMX-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 5 is NC (no connect); pins 1, 4, 7, and 8 are all ground terminals requiring low-impedance connection to PCB ground plane.

Key Features

Applications

Equivalent & Alternatives

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

Compared with REF3012AIDBZR and ADR3412ARJZ-R7, the LM4140CCMX-1.2/NOPB delivers the lowest combined error envelope (initial + tempco + noise) for battery-powered precision systems, though it requires more PCB area and a mandatory 1-µF output capacitor.

Availability

LM4140CCMX-1.2/NOPB is available at Aetrix Electronics and suitable for portable instrumentation, precision data acquisition, battery-powered medical sensors, and automotive cabin monitoring requiring stable component supply with full traceability and long-term lifecycle support.

Supply support for LM4140CCMX-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 company headquartered in Dallas, Texas, designing and manufacturing analog and embedded processing chips for industrial, automotive, and personal electronics markets.

The LM4140 product line was developed to deliver ultra-stable, low-power voltage references for portable and battery-operated precision measurement systems where traditional bandgap references could not meet sub-ppm/°C stability targets.

FAQ

What is the minimum input voltage required for stable operation of LM4140CCMX-1.2/NOPB?

The LM4140CCMX-1.2/NOPB requires a minimum input voltage of V_REF + 20 mV (1.27 V) at 1 mA load to maintain regulation within specification. At higher loads or elevated temperatures, the dropout voltage increases-up to 45 mV over 0°C to 70°C. For reliable operation across full temperature and load range, TI recommends maintaining VIN ≥ 1.3 V. This low dropout enables direct use with single-cell lithium batteries throughout their discharge curve.

Does LM4140CCMX-1.2/NOPB require an input capacitor?

The LM4140CCMX-1.2/NOPB does not require an input capacitor for basic regulation, but Texas Instruments recommends a 0.1 µF ceramic capacitor placed close to the VIN pin to improve transient response and reduce high-frequency noise coupling. Unlike the mandatory 1-µF output capacitor, the input capacitor is optional and serves only to enhance dynamic performance-not stability. Its absence will not cause oscillation or failure, but may degrade PSRR above 10 kHz.

Can LM4140CCMX-1.2/NOPB drive a 10 kΩ load directly?

Yes, the LM4140CCMX-1.2/NOPB can directly drive a 10 kΩ load (125 µA current) with negligible error. Its specified load regulation is 1–20 ppm/mA over 1–8 mA, translating to <±2.5 µV change at 125 µA-well within its 0.1% (1.25 mV) initial accuracy. For loads below 1 mA, output voltage deviation remains dominated by temperature coefficient and long-term drift rather than load effects, making it suitable for high-impedance ADC reference inputs and op-amp bias networks.

What is the purpose of the NC pin (Pin 5) on LM4140CCMX-1.2/NOPB?

Pin 5 on the LM4140CCMX-1.2/NOPB is designated NC (No Connect) and must remain unconnected-neither tied to ground, supply, nor left floating. Internally, it is not bonded and has no electrical function. Soldering or routing to this pin risks mechanical stress on the die bond wire or contamination during assembly, potentially degrading long-term reliability. TI's datasheet explicitly states "This pin must be left open," and violating this violates the device's qualified SOIC-8 package construction.

How does the enable pin of LM4140CCMX-1.2/NOPB behave during power-up?

The LM4140CCMX-1.2/NOPB enable pin (Pin 3) requires a valid logic high (≥0.8×V_IN) to activate the reference; if left floating during power-up, the internal state is undefined and may result in erratic output or latch-up. TI specifies that the enable pin must be actively driven-either tied to VIN for permanent enable or controlled by a clean digital signal. During power-up sequencing, V_IN must stabilize before the enable signal transitions high to ensure proper internal biasing and avoid output overshoot exceeding 200 µs turn-on time.