Texas Instruments LM4140BCMX-1.0

Overview

LM4140BCMX-1.0 from Texas Instruments is a high-precision, low-noise, low-dropout series voltage reference delivering 1.024 V output with ±0.1% initial accuracy, 3 ppm/°C temperature coefficient (B grade), and 2.2 µV_PP (0.1–10 Hz) output noise. It operates down to 1.8 V input, supports up to 8 mA load, and features an enable pin for shutdown mode consuming ≤1 µA - ideal for precision ADC/DAC biasing in portable instrumentation.

For engineers reviewing the LM4140BCMX-1.0 datasheet, LM4140BCMX-1.0 pinout, LM4140BCMX-1.0 application, or LM4140BCMX-1.0 equivalent, key selection considerations include its sub-bandgap 1.024 V output, EEPROM-trimmed curvature correction, SOIC-8 package compatibility, and requirement for a mandatory 1 µF output capacitor for stability.

Technical Context

The LM4140BCMX-1.0 uses a P-channel pass transistor architecture with integrated CMOS DACs and EEPROM registers for factory trimming of both initial accuracy and temperature coefficient curvature. Its series topology enables operation with VIN as low as VREF + 400 mV over temperature while maintaining regulation.

It implements active output discharge during disable via internal circuitry, achieving VREF turn-on in <200 µs and full shutdown with ≤1 µA supply current. The enable pin accepts logic-level control referenced to VIN, requiring no external pull-up when tied directly to VIN for always-on operation.

Key Specifications

Pinout & Package

LM4140BCMX-1.0 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 ADR3410ARJZ-R7, LM4140BCMX-1.0 provides superior 1.024 V output alignment for 10-bit systems, lower 2.2 µV_PP noise, and EEPROM-trimmed 6 ppm/°C tempco - making it optimal for applications demanding ratiometric accuracy, low-frequency stability, and configurable power management.

Availability

LM4140BCMX-1.0 is available at Aetrix Electronics and suitable for portable instrumentation, precision data acquisition systems, and medical sensor modules requiring stable component supply with guaranteed long-term continuity and traceable lot documentation.

Supply support for LM4140BCMX-1.0 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 specifically for high-accuracy, low-power, low-noise voltage referencing in battery-operated and portable measurement equipment - emphasizing factory-trimmed stability without laser calibration.

FAQ

What is the required output capacitor for stable operation of the LM4140BCMX-1.0?

The LM4140BCMX-1.0 requires a minimum 1 µF ceramic capacitor connected between the VREF pin and GND for loop stability and transient response. Values below 0.2 µF risk oscillation; ESR must fall within the 1–10 Ω range per TI's Figure 23. Tantalum and multilayer ceramic capacitors meeting these criteria are validated in the datasheet. Using less than 1 µF violates the stability guarantee for LM4140BCMX-1.0.

Does the LM4140BCMX-1.0 support true shutdown with zero output current?

Yes - when the Enable pin is driven below 0.4 V, the LM4140BCMX-1.0 enters shutdown mode with supply current ≤1 µA and VREF actively discharged to GND via internal circuitry. Output voltage drops to 0 V within microseconds, eliminating leakage paths. This behavior is confirmed in Section 7.3.1 and Figure 2 of the LM4140BCMX-1.0 datasheet.

Can the LM4140BCMX-1.0 operate from a 1.8 V supply while delivering full 8 mA load current?

Yes - the LM4140BCMX-1.0 supports 1.8 V minimum input across its full 0°C to 70°C operating range. At 1 mA load, dropout is 20 mV typical; at 8 mA, it rises to 235 mV maximum (per Table 6.5). Thus, 1.8 V input sustains regulation for LM4140BCMX-1.0 only up to ~5.5 mA load at worst-case temp - verify actual load and thermal conditions per the dropout vs. current curves in Figure 7.

How does the LM4140BCMX-1.0 achieve 0.1% initial accuracy without laser trimming?

The LM4140BCMX-1.0 achieves ±0.1% initial accuracy using factory-programmed EEPROM registers that control integrated CMOS DACs. These DACs adjust bias currents and curvature compensation in the bandgap core - a method providing higher trimming resolution than traditional laser-zapping of thin-film resistors. This is explicitly described in Section 3 (Description) of the LM4140BCMX-1.0 datasheet.

Is the NC pin (Pin 5) on the LM4140BCMX-1.0 safe to connect to ground or leave floating?

Pin 5 (NC) on the LM4140BCMX-1.0 must remain unconnected - neither grounded nor left floating with stub traces. TI specifies it as "no-connect" in the Pin Functions table (Section 5), and connecting it risks parasitic coupling or EMI susceptibility. Board layouts must omit any copper or solder mask at Pin 5 to prevent unintended interaction with the LM4140BCMX-1.0's internal circuitry.