Analog Devices Inc./Maxim Integrated LM4040DIX3-2.1-T

Overview

LM4040DIX3-2.1-T from Maxim Integrated is a precision 2.048V two-terminal shunt voltage reference in SC70-3 package, featuring ±1.0% initial accuracy, ±150ppm/°C temperature coefficient over –40°C to +85°C, 60μA–15mA operating current range, and 28μVRMS wideband noise (10Hz–10kHz). It serves as a stable reference in portable battery-powered systems where space and low quiescent current are critical.

For engineers reviewing the LM4040DIX3-2.1-T datasheet, LM4040DIX3-2.1-T pinout, LM4040DIX3-2.1-T application, or LM4040DIX3-2.1-T equivalent, this page delivers verified electrical parameters, SC70-3 terminal mapping, real-world use cases in notebook computers and industrial controls, and validated alternative options for design flexibility and supply continuity.

Technical Context

The LM4040DIX3-2.1-T implements a bandgap-based shunt reference architecture, functioning like a precision zener diode with reverse breakdown voltage fixed at 2.048V. Its internal laser-trimmed resistor network ensures factory-set accuracy, while low dynamic impedance (≤1.1Ω at 1mA) maintains regulation across load and temperature variations.

No external capacitor is required for stability - the device remains stable under any capacitive load condition. It operates without forward conduction, drawing only reverse current (cathode-to-anode), and tolerates up to 20mA absolute maximum reverse current without damage.

Key Specifications

Pinout & Package

LM4040DIX3-2.1-T uses the 3-pin SC70 surface-mount package (1.8mm × 1.8mm), 50% smaller than SOT23. Pin 3 is no-connect (N.C.) and must remain unconnected 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 LM4040DIX3-2.1-T, TLVH431ACDBVR offers voltage adjustability at the cost of accuracy and external component dependency, while REF3020AIDBZR delivers superior accuracy and tempco but demands higher PCB area and external capacitance - making LM4040DIX3-2.1-T optimal for space-constrained, fixed-voltage, moderate-accuracy shunt reference roles.

Availability

LM4040DIX3-2.1-T is available at Aetrix Electronics and suitable for portable medical sensors, notebook computer power monitoring, and industrial process transmitters requiring stable component supply with lead-free RoHS compliance and tape-and-reel packaging.

Supply support for LM4040DIX3-2.1-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 (now part of Analog Devices) designs precision analog, mixed-signal, and power management ICs for demanding industrial, automotive, and computing applications.

The LM4040 product line delivers micropower, high-accuracy shunt voltage references optimized for space-constrained, battery-operated, and thermally variable environments - targeting portable instrumentation and embedded control systems.

FAQ

What is the exact reference voltage tolerance of LM4040DIX3-2.1-T over its full operating temperature range?

The LM4040DIX3-2.1-T has a nominal reverse breakdown voltage of 2.048V at +25°C, with a guaranteed range of 2.028V to 2.068V (±1.0%) at room temperature. Over –40°C to +85°C, total tolerance expands to ±1.98% (±41mV) due to ±150ppm/°C tempco, as confirmed in Maxim's datasheet Note 2. This includes both initial trim error and temperature-induced drift.

Can LM4040DIX3-2.1-T operate reliably below 60μA shunt current?

No - the LM4040DIX3-2.1-T requires a minimum operating current of 60μA to maintain regulation and specified accuracy. Below this threshold, output voltage deviates significantly (e.g., >50mV drop at 45μA), and tempco performance degrades. The datasheet explicitly specifies 60μA as the lower bound for guaranteed operation across temperature.

Is pin 3 of LM4040DIX3-2.1-T required to be grounded or left floating?

Pin 3 of LM4040DIX3-2.1-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; connecting it elsewhere may cause no functional impact but violates the manufacturer's mechanical and reliability guidance. The SC70-3 top marking "ABM" confirms this variant's N.C. configuration.

How does LM4040DIX3-2.1-T compare to LM4040CIX3-2.1+T in terms of long-term stability?

Both LM4040DIX3-2.1-T and LM4040CIX3-2.1+T specify identical long-term stability: 120ppm change after 1000 hours of operation. The difference lies in initial accuracy (±1.0% vs. ±0.5%) and tempco (±150ppm/°C vs. ±100ppm/°C), not aging behavior. Long-term drift is process-dependent and consistent across LM4040 grades per Maxim's characterization data.

Does LM4040DIX3-2.1-T require an external capacitor for stability in high-frequency noise environments?

No - LM4040DIX3-2.1-T is inherently stable with any capacitive load and does not require an external output capacitor. Its internal design ensures phase margin >45° across 0.1pF to 10µF loads, as verified in typical operating characteristics (Figure 14–15). Adding capacitance may reduce noise but introduces no stability risk.