Diodes Incorporated LM4040C50FTA

Overview

LM4040C50FTA from Diodes Incorporated is a precision 5.0V shunt voltage reference in SOT23 package, rated for ±0.5% initial tolerance at +25°C, 60µA–15mA operating current, and −40°C to +125°C temperature range. It delivers low 80µVRMS noise (10Hz–10kHz) and 30ppm/°C max tempco over full industrial range, serving as a stable reference in battery-powered analog signal chains.

For engineers reviewing the LM4040C50FTA datasheet, LM4040C50FTA pinout, LM4040C50FTA application, or LM4040C50FTA equivalent, key selection criteria include reverse breakdown voltage stability under varying load current, capacitive-load tolerance without external capacitor, thermal hysteresis (<0.08%), and compatibility with space-constrained PCB layouts requiring SOT23 footprint.

Technical Context

The LM4040C50FTA operates as a two-terminal bandgap shunt reference, sinking current through its cathode to maintain precise 5.0V reverse breakdown voltage across its anode–cathode terminals. Its internal architecture achieves high stability via curvature-compensated bandgap core and optimized die layout for low thermal hysteresis.

It functions without output capacitance and remains stable with up to 1.0µF tantalum load capacitance, supporting direct integration into ADC reference inputs, DAC bias networks, and portable power monitor circuits where low quiescent current and minimal board area are critical.

Key Specifications

Pinout & Package

SOT23-3 package with exposed die attached to pin 3; pin 3 must be left floating or connected to pin 2 per layout guidelines. Pin 2 must be left floating or connected to pin 1. No SC70-5 variant is active-only SOT23 is in full production.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLV431ACDBVR and MAX6008AEUR+T, the LM4040C50FTA offers the lowest operating current (60µA), best temperature coefficient (30ppm/°C max), and simplest implementation (no external resistors), making it optimal for battery life–critical and thermally demanding embedded systems.

Availability

LM4040C50FTA is available at Aetrix Electronics and suitable for battery-powered instrumentation, precision data acquisition, portable communications devices, and notebook power monitoring requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for LM4040C50FTA 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

Diodes Incorporated is a global semiconductor company specializing in discrete, analog, and mixed-signal solutions, with emphasis on high-reliability, energy-efficient components for industrial, computing, and consumer markets.

The LM4040 series was designed specifically for space-constrained, low-power precision analog systems requiring stable voltage references without external compensation-targeting portable, battery-operated, and thermally variable applications.

FAQ

What is the minimum operating current for LM4040C50FTA at −40°C?

The minimum operating current is 83µA at −40°C to +125°C ambient, verified per Electrical Characteristics table for LM4040-50 C-grade. Below this current, regulation degrades beyond ±0.5% tolerance, risking reference inaccuracy in cold-environment deployments such as outdoor IoT sensors.

Can LM4040C50FTA drive a 1000pF capacitive load without oscillation?

Yes-LM4040C50FTA is explicitly characterized for stability with up to 1.0µF tantalum capacitive loads and exhibits no oscillation with 1000pF ceramic loads. Its internal compensation ensures phase margin remains >45° across full operating current and temperature range, eliminating need for series resistance.

Is pin 3 of LM4040C50FTA electrically connected to any internal node?

Yes-pin 3 is the die attach pad and is electrically tied to pin 2 (cathode) inside the SOT23 package. Per datasheet layout guidance, pin 3 must either float or be shorted to pin 2; connecting it to any other net violates internal routing and risks thermal or electrical malfunction.

How does long-term stability impact calibration interval in metrology equipment?

With 120ppm drift over 1000 hours (≈6 weeks continuous operation), LM4040C50FTA contributes <0.012% error growth per 1000h. In Class I handheld calibrators, this supports 12-month recalibration cycles if initial tolerance (±0.5%) and tempco (±3.75mV) dominate total error budget.