Texas Instruments LM4128BMF-3.0

Overview

LM4128BMF-3.0 from Texas Instruments (formerly National Semiconductor) is a precision micropower series voltage reference in SOT-23-5 package, delivering 3.0 V output with ±0.2% initial accuracy, 75 ppm/°C temperature coefficient, and 60 µA quiescent current. It features an enable pin for 3 µA shutdown mode, supports up to 20 mA load, and operates across −40°C to +125°C - ideal for battery-powered instrumentation and portable data acquisition systems.

For engineers reviewing the LM4128BMF-3.0 datasheet, LM4128BMF-3.0 pinout, LM4128BMF-3.0 application, or LM4128BMF-3.0 equivalent, key selection considerations include dropout voltage (≤400 mV at 10 mA), stability with capacitive loads up to 10 µF, line regulation (70 ppm/V), load regulation (25–120 ppm/mA), and thermal hysteresis (75 ppm).

Technical Context

The LM4128BMF-3.0 uses a band-gap-derived reference core optimized for low-power operation and high DC precision. Its series architecture eliminates need for external stabilization capacitors while maintaining stability with ceramic output capacitance up to 10 µF.

It integrates an enable input (EN) referenced to VIN, with logic thresholds at 35% and 65% of VIN, enabling seamless integration into power-managed systems. Dropout voltage remains ≤400 mV at 10 mA load, supporting operation from as low as 3.4 V input supply.

Key Specifications

Pinout & Package

SOT-23-5 package (NS package number MF05A), surface-mount, 5-terminal plastic case with exposed pad not electrically connected. Dimensions per JEDEC MO-178AA.

Key Features

Applications

Equivalent & Alternatives

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

Compared with REF3030AIDBZR, LM4128BMF-3.0 provides enable control and higher output drive (20 mA vs 15 mA) at the cost of slightly higher tempco; versus ADR3430ARJZ-R7, it delivers 50% lower quiescent current but trades off 6.5× higher temperature coefficient.

Availability

LM4128BMF-3.0 is available at Aetrix Electronics and suitable for portable instrumentation, battery-powered test equipment, and industrial data acquisition systems requiring stable component supply, consistent parametric performance, and long-term manufacturing continuity.

Supply support for LM4128BMF-3.0 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 acquired National Semiconductor in 2011 and maintains full product support, datasheets, and application engineering for legacy references including the LM4128 family.

The LM4128 series was designed specifically for space-constrained, low-power precision analog systems - emphasizing micropower operation, SOT-23 integration, and robustness across automotive and industrial temperature ranges.

FAQ

What is the minimum input voltage required for stable operation of the LM4128BMF-3.0?

The LM4128BMF-3.0 requires VIN ≥ VREF + 400 mV, i.e., ≥3.4 V at 10 mA load. At lighter loads, dropout decreases - e.g., 200 mV typical at 10 mA for 3.0 V version - but 3.4 V ensures guaranteed 3.0 V output within spec across temperature and process variation. Below this, output regulation degrades nonlinearly.

Does the LM4128BMF-3.0 require an input capacitor, and what value is recommended?

Yes - a minimum 0.1 µF ceramic (X5R/X7R) input capacitor (CIN) is mandatory for stability. When using an output capacitor (COUT), CIN must be ≥ COUT. For optimal noise suppression and startup behavior, 4.7 µF to 22 µF input capacitance is recommended, placed close to the VIN and GND pins of the LM4128BMF-3.0.

Can the LM4128BMF-3.0 drive a 10 µF capacitive load without oscillation?

Yes - the LM4128BMF-3.0 is explicitly characterized and guaranteed stable with capacitive loads up to 10 µF, including low-ESR ceramic types. This eliminates need for isolation resistors or damping networks typically required with older references, simplifying design and improving transient response.

What is the function of Pin 1 (N/C) on the LM4128BMF-3.0, and how should it be handled?

Pin 1 is a no-connect terminal - physically present but not bonded to any internal circuitry. It must be left floating (unconnected) on the PCB. Routing traces or applying solder to Pin 1 may induce mechanical stress or parasitic coupling that affects output voltage stability or thermal hysteresis performance of the LM4128BMF-3.0.

How does the enable pin (Pin 3) interface with common microcontrollers?

The LM4128BMF-3.0 EN pin has an internal ~2 µA pull-up and accepts logic-high at ≥65% of VIN (e.g., ≥2.21 V when VIN = 3.4 V). A standard 3.3 V GPIO can directly drive EN high; for 1.8 V logic, use a level-shifting buffer or resistor divider. Driving EN low (<35% VIN) places LM4128BMF-3.0 in 3 µA shutdown mode with full output disable.