Analog Devices Inc./Maxim Integrated LM4040BEX3-3.3+T

Overview

LM4040BEX3-3.3+T from Maxim Integrated is a precision 3.3V two-terminal shunt voltage reference in SC70-3 package, featuring 0.2% initial accuracy, ±100ppm/°C temperature coefficient, and guaranteed operation from −40°C to +125°C. It delivers stable reverse breakdown voltage with 60μA–15mA shunt current capability and low 50μVRMS wideband noise (10Hz–10kHz), ideal for high-accuracy analog sensing and power supply feedback in space-constrained portable electronics.

For engineers reviewing the LM4040BEX3-3.3+T datasheet, LM4040BEX3-3.3+T pinout, LM4040BEX3-3.3+T application, or LM4040BEX3-3.3+T equivalent, key selection criteria include its fixed 3.3V output, SC70-3 footprint compatibility, AEC-Q100-qualified extended temperature range, and absence of required output capacitance-critical for battery-powered instrumentation and automotive subsystems requiring long-term stability and low quiescent current.

Technical Context

The LM4040BEX3-3.3+T uses bandgap-based shunt regulation to maintain a precise 3.3V reverse breakdown voltage across its anode and cathode terminals without external components. Its internal laser-trimmed resistor network ensures tight initial tolerance, while thermal design guarantees ≤±100ppm/°C drift over −40°C to +125°C.

It operates as a two-terminal device with no ground reference needed, sinking 60μA–15mA shunt current to regulate voltage. The NC pin (Pin 3) must remain unconnected or tied to cathode, preserving SC70-3 mechanical integrity and electrical performance under capacitive loads up to 1µF.

Key Specifications

Pinout & Package

LM4040BEX3-3.3+T is housed in a RoHS-compliant 3-pin SC70 surface-mount package (1.8mm × 1.8mm), 50% smaller than SOT23 equivalents. Pin 3 is No Connect (NC) and must be left floating or tied to Pin 2 per datasheet requirement.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLVH431ACDBVR and REF3033AIDBZR, LM4040BEX3-3.3+T offers superior thermal stability in shunt configuration, eliminates external resistors, and supports true two-terminal operation-making it optimal for ultra-compact, low-power, and high-reliability designs where layout simplicity and long-term drift matter most.

Availability

LM4040BEX3-3.3+T is available at Aetrix Electronics and suitable for portable medical sensors, automotive cabin controllers, industrial process transmitters, and smart energy meters requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for LM4040BEX3-3.3+T 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

Maxim Integrated is a semiconductor company specializing in analog and mixed-signal ICs for power management, sensing, and communication applications.

The LM4040 product line delivers precision shunt voltage references optimized for space-constrained, battery-powered, and automotive systems demanding high accuracy, low noise, and extended temperature operation without external compensation.

FAQ

What is the exact output voltage tolerance of LM4040BEX3-3.3+T at +25°C?

The LM4040BEX3-3.3+T has a nominal reverse breakdown voltage of 3.300V with a tolerance of ±6.0mV (±0.2%) at +25°C, as specified in the Electrical Characteristics table for the B-grade 3.3V variant. This corresponds to a guaranteed range of 3.294V to 3.306V under standard test conditions, enabling high-fidelity reference performance in precision analog circuits.

Does LM4040BEX3-3.3+T require an external capacitor for stability?

No, LM4040BEX3-3.3+T does not require an external output capacitor for stability. Its internal design ensures unconditional stability with any capacitive load, including values up to 1µF. This eliminates BOM cost, reduces PCB area, and avoids potential phase-margin issues-making LM4040BEX3-3.3+T especially suitable for compact, low-component-count applications like wearable health monitors.

What is the maximum operating temperature range for LM4040BEX3-3.3+T?

The LM4040BEX3-3.3+T is rated for operation from −40°C to +125°C, as indicated by the "E" suffix in its part number (LM4040BEX3-3.3+T). This extended temperature range meets AEC-Q100 requirements for automotive under-hood and industrial environments, and is validated across all electrical parameters in the datasheet's E-grade specifications.

How is the NC pin (Pin 3) of LM4040BEX3-3.3+T configured in circuit design?

Pin 3 of LM4040BEX3-3.3+T is designated N.C. (No Connection) and must either be left unconnected or tied directly to Pin 2 (cathode). It is not internally bonded and serves only as a mechanical placeholder in the SC70-3 package. Incorrect connection-such as tying Pin 3 to V_IN or leaving it floating without referencing Pin 2-may compromise thermal performance or long-term reliability per Maxim's pin configuration guidance.

What is the minimum shunt current required for LM4040BEX3-3.3+T to maintain regulation?

The LM4040BEX3-3.3+T requires a minimum shunt current of 67μA to maintain regulation across its full temperature range (−40°C to +125°C), as specified in the Electrical Characteristics table for the 3.3V B-grade variant. At +25°C, the typical minimum is 67μA, with a maximum of 73μA-ensuring reliable startup and regulation even under worst-case process and temperature conditions.