Texas Instruments LM4140BCM-1.2/NOPB

Overview

LM4140BCM-1.2/NOPB from Texas Instruments is a high-precision, low-noise, low-dropout series voltage reference delivering 1.25 V output with ±0.1% initial accuracy, 3 ppm/°C temperature coefficient (A grade), and 20 mV typical dropout at 1 mA. It features an enable pin for power management and operates down to 1.8 V input, making it ideal for precision ADC/DAC biasing in portable instrumentation.

For engineers reviewing the LM4140BCM-1.2/NOPB datasheet, LM4140BCM-1.2/NOPB pinout, LM4140BCM-1.2/NOPB application, or LM4140BCM-1.2/NOPB equivalent, key selection criteria include ultra-low 2.2 µV_PP (0.1–10 Hz) noise, ≤1 µA shutdown current, 8 mA output drive, and SOIC-8 package compatibility with standard PCB layouts for metrology-grade signal chains.

Technical Context

The LM4140BCM-1.2/NOPB uses EEPROM-trimmed CMOS DACs for curvature-corrected temperature compensation and output voltage trimming-enabling sub-0.1% accuracy without laser trimming. Its P-channel pass transistor architecture supports operation with VIN as low as VREF + 200 mV over temperature.

It integrates internal charge-discharge circuitry on the enable pin to rapidly discharge the output capacitor during shutdown (<200 µs turn-on), ensuring clean power sequencing in battery-powered systems where ground-current spikes must be minimized.

Key Specifications

Pinout & Package

LM4140BCM-1.2/NOPB is housed in an 8-pin SOIC package (4.90 mm × 3.91 mm body size) with exposed pad not present; thermal resistance R_θJA = 119.3°C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with REF3012AIDBZR and ADR3412ARJZ-R7, LM4140BCM-1.2/NOPB uniquely combines 1.25 V output, 3 ppm/°C tempco, enable control, and 1.8 V operation in SOIC-8-making it the only option for high-accuracy, low-voltage, power-gated applications without redesigning supply architecture.

Availability

LM4140BCM-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 across multi-year production cycles.

Supply support for LM4140BCM-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 specializing in analog and embedded processing technologies, with leadership in precision analog ICs since the 1960s.

The LM4140 product line was designed specifically for high-accuracy, low-noise, low-power voltage reference applications in portable, industrial, and medical equipment-addressing the need for sub-0.1% initial accuracy without laser trimming.

FAQ

What is the maximum load current supported by LM4140BCM-1.2/NOPB?

The LM4140BCM-1.2/NOPB is specified to source up to 8 mA while maintaining output accuracy within datasheet limits. At 8 mA load, dropout voltage rises to 235 mV (max) over temperature. For higher currents, external buffering-such as a PNP transistor boost stage-is required, as shown in TI's Figure 30 application schematic. Exceeding 8 mA may cause VREF deviation beyond ±0.1%.

Does LM4140BCM-1.2/NOPB require an output capacitor, and what type is recommended?

Yes, LM4140BCM-1.2/NOPB requires a minimum 1 µF output capacitor connected between VREF and GND for loop stability and transient response. TI validates solid tantalum (e.g., Kemet T491A105M010AS) and multilayer ceramic (e.g., Murata GRM42-6Y5V225Z16) types. Ceramic capacitors must meet ESR requirements per Figure 23; values below 0.2 µF risk instability. Aluminum electrolytics are discouraged due to ESR drift at low temperatures.

Can LM4140BCM-1.2/NOPB operate from a 1.8 V supply?

Yes, LM4140BCM-1.2/NOPB is explicitly rated for operation down to 1.8 V input (VIN ≥ VREF + 200 mV). At 1.8 V and 1 mA load, dropout is 20 mV typical, leaving sufficient headroom. The device maintains full specification compliance-including 0.1% initial accuracy and 3 ppm/°C tempco-across 1.8 V to 5.5 V input range, making it suitable for single-cell Li-ion and energy-harvesting systems.

How does the enable pin function on LM4140BCM-1.2/NOPB, and what happens during shutdown?

The enable pin (Pin 3) is active-high: driving it ≥0.8×VIN turns on the reference; pulling it ≤0.4 V disables output and reduces supply current to ≤1 µA. During shutdown, internal circuitry actively discharges the output capacitor to GND-ensuring VREF reaches 0 V within microseconds. This eliminates need for external bleed resistors and prevents voltage hold-up in power-gated subsystems.

Is LM4140BCM-1.2/NOPB pin-compatible with other LM4140 variants like LM4140ACM-1.2/NOPB?

Yes, all LM4140 variants-including LM4140BCM-1.2/NOPB and LM4140ACM-1.2/NOPB-share identical SOIC-8 pinout, electrical interface, and footprint. The suffix denotes grade: 'A' = 3 ppm/°C, 'B' = 6 ppm/°C, 'C' = 10 ppm/°C tempco. LM4140BCM-1.2/NOPB is B-grade (6 ppm/°C), not A-grade. Substituting grades affects temperature-induced drift but requires no PCB changes.