Diodes Incorporated LM4040D41QFTA

Overview

LM4040D41QFTA from Diodes Incorporated is a precision micropower shunt voltage reference with 4.096 V nominal reverse breakdown voltage, ±1% initial tolerance at +25°C, and AEC-Q100 qualification for automotive applications. It operates over 60 µA to 15 mA current range, maintains stability with capacitive loads, and delivers 100 ppm/°C max temperature coefficient across –40°C to +125°C. Used in automotive data acquisition systems for ADC biasing and sensor excitation.

For engineers reviewing the LM4040D41QFTA datasheet, LM4040D41QFTA pinout, LM4040D41QFTA application, or LM4040D41QFTA equivalent, key selection criteria include reverse breakdown voltage accuracy, temperature coefficient, minimum operating current (83 µA at +25°C), dynamic output impedance (1.3 Ω at 1 mA), and SOT23 package compatibility with space-constrained automotive PCB layouts.

Technical Context

The LM4040D41QFTA implements a bandgap-based shunt reference architecture optimized for low-power, high-stability operation in automotive environments. Its design supports stable regulation without an external output capacitor and tolerates wide capacitive loading-critical for noise-sensitive analog front-ends in engine control units and battery management systems.

It functions as a two-terminal device: anode and cathode. Regulation occurs when reverse current flows through the cathode-to-anode path, establishing a precise 4.096 V reference potential relative to the anode. The device's thermal hysteresis is limited to 0.08%, and long-term stability is 120 ppm over 1000 hours at 100 µA.

Key Specifications

Pinout & Package

The LM4040D41QFTA is housed in a standard SOT23-3L surface-mount package (JEDEC TO-236AB). Pin 3 (tab) is internally connected to pin 2 (cathode); therefore, pin 3 must be left floating or tied to pin 2 per manufacturer layout guidance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLVH431AQDBVRQ1 and MAX6008AEUR+T, the LM4040D41QFTA offers optimal balance of fixed 4.096 V accuracy, AEC-Q100 assurance, and minimal board footprint-making it the preferred choice for production automotive systems requiring zero-trim, drop-in reference solutions.

Availability

LM4040D41QFTA is available at Aetrix Electronics and suitable for engine control units, battery management systems, and ADAS camera modules requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for LM4040D41QFTA 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 devices for automotive, industrial, and computing markets, with manufacturing certified to IATF 16949 and AEC-Q100 standards.

The LM4040Q series belongs to Diodes' automotive-qualified precision reference portfolio, engineered specifically to replace legacy LM4040 variants in safety-critical vehicle subsystems while maintaining pin-for-pin compatibility and enhanced thermal stability.

FAQ

What is the maximum reverse current rating for LM4040D41QFTA?

The absolute maximum continuous reverse current is 20 mA. Operation beyond this limit risks permanent damage. For reliable regulation, the device must be biased between its minimum operating current (83 µA at +25°C) and 15 mA-the maximum recommended operating current per datasheet specifications.

Can LM4040D41QFTA drive capacitive loads directly?

Yes-the device is explicitly designed to maintain stability with capacitive loads up to at least 1.0 µF tantalum, as confirmed by typical impedance and noise characterization curves. No series resistance or isolation buffer is required, simplifying layout in automotive sensor interfaces where decoupling capacitance is mandatory.

How does the SOT23 pin 3 connection affect PCB layout?

Pin 3 (the thermal tab) is electrically bonded to pin 2 (cathode) inside the package. Therefore, the PCB land pattern must either leave pin 3 unconnected (floating) or tie it directly to the cathode net. Using pin 3 as an independent node violates the internal construction and may cause regulation failure or parametric shift.

Is LM4040D41QFTA compatible with lead-free reflow processes?

Yes-it is fully RoHS 3 compliant, with matte tin-plated leads qualified per MIL-STD-202, Method 208. The device supports standard JEDEC J-STD-020 moisture sensitivity Level 1 handling and withstands peak reflow temperatures up to 260°C, making it compatible with standard lead-free assembly lines used in automotive electronics manufacturing.