Texas Instruments LM4128DMF-4.1

Overview

LM4128DMF-4.1 from Texas Instruments (formerly National Semiconductor) is a precision micropower series voltage reference in SOT-23-5 package, delivering 4.096 V output with ±1.0% initial accuracy and 100 ppm/°C temperature coefficient over −40°C to +125°C. It features 60 µA quiescent current, 400 mV dropout voltage at 10 mA load, and an enable pin supporting 3 µA shutdown mode-ideal for battery-powered instrumentation and portable data acquisition systems.

For engineers reviewing the LM4128DMF-4.1 datasheet, LM4128DMF-4.1 pinout, LM4128DMF-4.1 application, or LM4128DMF-4.1 equivalent, key selection considerations include its D-grade accuracy and tempco specification, SOT-23-5 footprint compatibility, enable-controlled power gating, and stability with up to 10 µF capacitive loads without external compensation.

Technical Context

The LM4128DMF-4.1 implements a band-gap–derived series reference architecture with internal enable logic and short-circuit protection. Its design eliminates need for external stabilization capacitors while maintaining stability with ceramic output capacitance up to 10 µF, and supports input voltages from VREF + 400 mV (4.496 V) to 5.5 V.

It operates across −40°C to +125°C junction temperature range, delivers up to 20 mA output current, and exhibits 350 µVPP (0.1–10 Hz) output noise and 50 ppm long-term stability over 1000 hours-enabling use in precision ADC biasing and closed-loop regulation where drift and noise impact measurement fidelity.

Key Specifications

Pinout & Package

SOT-23-5 package (NS package number MF05A), 1.6 mm × 2.9 mm footprint, 1.1 mm height, gull-wing leads. RoHS-compliant, lead-free finish.

Key Features

Applications

Equivalent & Alternatives

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

Compared with REF3040AIDBZR and MAX6029AEUR+T, the LM4128DMF-4.1 trades higher initial error and tempco for guaranteed operation up to +125°C junction temperature and integrated enable functionality in the same SOT-23-5 package-making it optimal for cost-sensitive, wide-temperature industrial designs where moderate accuracy suffices.

Availability

LM4128DMF-4.1 is available at Aetrix Electronics and suitable for instrumentation & process control, portable battery-powered equipment, and data acquisition systems requiring stable component supply with consistent D-grade parametric performance across production lots.

Supply support for LM4128DMF-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 acquired National Semiconductor in 2011 and maintains legacy product lines including precision analog ICs. TI is a global leader in analog and embedded processing, with broad portfolio spanning voltage references, data converters, and power management.

The LM4128 series belongs to TI's precision voltage reference product line, designed specifically for space-constrained, low-power applications demanding stable DC bias-such as portable instrumentation, sensor signal chains, and battery-operated measurement systems.

FAQ

What is the output voltage tolerance of the LM4128DMF-4.1 over temperature?

The LM4128DMF-4.1 has a guaranteed temperature coefficient of 100 ppm/°C maximum over −40°C to +125°C junction temperature. At 4.096 V nominal output, this corresponds to a worst-case drift of ±0.512 V across the full range. The device also specifies 75 ppm thermal hysteresis and 50 ppm long-term stability over 1000 hours-parameters critical for uncalibrated field deployments where LM4128DMF-4.1 serves as the primary reference.

Does the LM4128DMF-4.1 require an input capacitor?

Yes-the LM4128DMF-4.1 requires a minimum 0.1 µF ceramic input capacitor (X5R or X7R) when no output capacitor is used. If an output capacitor COUT is present, CIN must be ≥ COUT. This input capacitor ensures stability and suppresses supply noise that would otherwise modulate the 4.096 V reference output. Layout best practice mandates placing CIN within 2 mm of the LM4128DMF-4.1 VIN and GND pins to minimize parasitic inductance.

Can the LM4128DMF-4.1 drive a 10 µF load capacitance?

Yes-the LM4128DMF-4.1 is explicitly characterized for stability with capacitive loads up to 10 µF, including low-ESR ceramic types. This capability eliminates need for external isolation resistors or compensation networks. However, larger output capacitance increases turn-on time (e.g., 78.8 µs to 90% with 10 µF vs 33.2 µs with 1 µF), which must be accounted for in fast-wakeup applications using the LM4128DMF-4.1 enable pin.

What is the minimum input voltage required for regulation with the LM4128DMF-4.1?

The LM4128DMF-4.1 requires VIN ≥ VREF + 400 mV for proper regulation, i.e., ≥4.496 V at 10 mA load. Dropout voltage is specified up to 400 mV maximum at 10 mA, and line regulation remains valid across VREF + 400 mV ≤ VIN ≤ 5.5 V. Below 4.496 V, the output collapses nonlinearly-so LM4128DMF-4.1 is incompatible with 3.3 V or 3.6 V supply rails unless boosted.

How does the enable pin function on the LM4128DMF-4.1?

The EN pin (Pin 3) is an active-high digital control input. When pulled above 65% of VIN, the LM4128DMF-4.1 operates normally (60 µA IQ). When pulled below 35% of VIN, it enters shutdown mode drawing 3 µA. An internal 2 µA pull-up allows tying EN directly to VIN for always-on operation. The pin tolerates voltages up to VIN but must never exceed VIN-applying EN > VIN risks damage and invalidates LM4128DMF-4.1 functionality.