STMicroelectronics LM4040BECT-2.5

Overview

LM4040BECT-2.5 from STMicroelectronics is a precision micropower shunt voltage reference delivering a stable 2.5 V output with ±0.2% initial accuracy at 25 °C, 70 ppm/°C max temperature coefficient, and ultra-low 10 µA operating current - ideal for battery-powered instrumentation and portable data acquisition systems.

For engineers reviewing the LM4040BECT-2.5 datasheet, LM4040BECT-2.5 pinout, LM4040BECT-2.5 application, or LM4040BECT-2.5 equivalent, key selection criteria include low-current regulation capability (10 µA min), low-frequency noise (10 µV_p-p), capacitive-load stability, and SOT323-5L space-constrained packaging.

Technical Context

The LM4040BECT-2.5 operates as a two-terminal shunt reference, sinking current through its cathode to maintain precise 2.5 V across an external load. It achieves regulation without requiring a ground connection, enabling floating or high-side biasing configurations in analog signal chains.

Its internal bandgap core is trimmed for ±0.2% accuracy at 25 °C and exhibits 120 ppm thermal hysteresis over -40 °C to +125 °C. Dynamic impedance remains below 0.3 Ω across 10 µA–10 mA operating current, ensuring minimal output voltage shift under varying load conditions.

Key Specifications

Pinout & Package

SOT323-5L package: 1.25 mm × 2.10 mm footprint, 0.65 mm pitch, 5-pin configuration with 2 NC pins. Designed for high-density PCB layouts where board space is constrained.

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, LM4040BECT-2.5 uniquely balances ±0.2% accuracy, 10 µA operation, and SOT323-5L miniaturization - making it optimal for space- and power-constrained industrial and portable instrumentation.

Availability

LM4040BECT-2.5 is available at Aetrix Electronics and suitable for portable medical sensors, industrial data acquisition systems, and smart meter analog front-ends requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for LM4040BECT-2.5 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing analog, microcontroller, power, and sensor solutions for industrial, automotive, and consumer markets.

LM4040 belongs to ST's precision analog portfolio, engineered specifically for high-accuracy, low-power voltage reference applications in harsh-environment instrumentation and portable electronics.

FAQ

What is the minimum operating current required for regulation at 2.5 V?

The LM4040BECT-2.5 requires a minimum cathode current of 10 µA at 25 °C to maintain regulation. At full temperature range (-40 °C to +125 °C), the minimum increases to 12 µA for 2.5 V versions, as confirmed in Table 3 of DS13886 Rev 4.

Can the NC pins on the SOT323-5L package be grounded?

No - pins 2, 4, and 5 are internally unconnected and must remain floating or be tied to the anode (pin 3) only, per Figure 1 and note in DS13886 Rev 4. Grounding NC pins may induce leakage paths or degrade thermal performance.

How does the LM4040BECT-2.5 perform with capacitive loads?

It remains stable with output capacitance from 0 nF up to 1 µF, as shown in Figure 11 (Stability plane vs. C_OUT). No series resistance or external compensation is needed - a key advantage over older shunt references that oscillate with >10 nF loads.

Is the 2.5 V output guaranteed across the full -40 °C to +125 °C range?

Yes - the 2.5 V output is guaranteed over the full industrial temperature range, with total error bounded by initial ±0.2% accuracy plus ≤70 ppm/°C tempco drift, resulting in worst-case deviation of ±0.235% (±5.88 mV) at extremes, per Table 4 and thermal characterization data.