Texas Instruments LMV431BIMFX

Overview

LMV431BIMFX from Texas Instruments is a precision 1.24-V adjustable shunt regulator in SOT-23-3 package, offering 0.5% initial reference voltage tolerance, 55 µA minimum cathode current for regulation, 0.25 Ω dynamic output impedance, and operation across −40°C to +85°C. It functions as a low-voltage voltage reference or error amplifier in 3-V off-line switching regulators and low-dropout shunt-based power management circuits.

For engineers reviewing the LMV431BIMFX datasheet, LMV431BIMFX pinout, LMV431BIMFX application, or LMV431BIMFX equivalent, key selection criteria include its industrial temperature range, tight 1.24 V reference accuracy, low quiescent current, stable performance with capacitive loads ≥10 nF, and compatibility with standard SOT-23-3 PCB footprints.

Technical Context

The LMV431BIMFX implements a band-gap referenced shunt regulator architecture with negative feedback from cathode to adjust pin, enabling precise voltage setting via external resistor divider. Its internal op-amp-like control loop maintains cathode voltage at 1.24 V ±0.5% over temperature and load.

It operates with cathode voltages from 1.24 V up to 30 V and supports cathode currents from 55 µA to 15 mA. The device achieves 39 ppm/°C temperature coefficient and remains stable with capacitive loads between 10 nF and 50 pF - critical for noise-sensitive feedback paths in DC/DC converters.

Key Specifications

Pinout & Package

SOT-23-3 (DBZ) package, 2.92 mm × 1.30 mm body size, surface-mount, RoHS-compliant with Sn lead finish and Level-1 MSL rating.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLVH431ACDBVR and LM4040CIM3-ADJ/NOPB, the LMV431BIMFX uniquely combines industrial temperature range (−40°C to +85°C), 30 V cathode capability, and full adjustability - making it the only option among the three qualified for automotive or extended-temperature industrial shunt regulation.

Availability

LMV431BIMFX is available at Aetrix Electronics and suitable for 3-V off-line switching regulators, low-dropout shunt regulators, and voltage-monitoring circuits requiring stable component supply with guaranteed long-term manufacturability.

Supply support for LMV431BIMFX 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

Texas Instruments is a global semiconductor leader delivering analog and embedded processing solutions with deep expertise in precision analog ICs and power management.

The LMV431B series belongs to TI's precision shunt regulator product line, designed specifically for low-voltage, high-accuracy voltage reference and error amplification in cost-sensitive industrial and consumer power systems.

FAQ

What is the operating temperature range of the LMV431BIMFX?

The LMV431BIMFX is rated for industrial operation from −40°C to +85°C. This range is confirmed in the "Recommended Operating Conditions" table of the SNVS041G datasheet and applies specifically to the "I" grade (e.g., LMV431BIMFX). It is not rated for commercial (0°C to 70°C) or extended temperature ranges.

How does the LMV431BIMFX achieve 0.5% reference voltage accuracy?

The LMV431BIMFX achieves 0.5% initial tolerance at 25°C through laser-trimmed band-gap reference circuitry. Per the LMV431BC/LMV431BI Electrical Characteristics tables, its reference voltage is specified as 1.234 V to 1.246 V at 25°C - a ±0.5% deviation around the nominal 1.24 V - and this grade is explicitly assigned to part numbers containing "B" and "I" (e.g., LMV431BIMFX).

Can the LMV431BIMFX replace a Zener diode in existing designs?

Yes, the LMV431BIMFX can directly replace many Zener diodes in shunt regulator or voltage reference roles. Unlike Zeners, it offers superior 0.5% tolerance, lower dynamic impedance (0.25 Ω vs. typical Zener >10 Ω), and stable operation down to 1.24 V. However, it requires three terminals (anode, cathode, adjust), so two-terminal Zener replacements require reworking the feedback network to include the adjust pin.

What is the minimum cathode current needed for regulation in the LMV431BIMFX?

The LMV431BIMFX requires a minimum cathode current of 55 µA to maintain regulation, as specified in the "LMV431BC" and "LMV431BI" Electrical Characteristics tables under I_Z(MIN). This value is guaranteed across the full −40°C to +85°C temperature range and enables reliable startup and regulation in ultra-low-power applications.

Is the LMV431BIMFX stable with ceramic output capacitors?

Yes, the LMV431BIMFX is stable with ceramic capacitors ranging from 10 nF to 50 pF, as documented in the "Typical Performance Characteristics" section (Figure 19, Stability Boundary Condition). For larger capacitors (>100 nF), stability depends on external series resistance; the device itself does not require added ESR and avoids the instability issues common with electrolytic or tantalum caps in shunt references.