Texas Instruments LM2931Z-5.0/LFT2

Overview

LM2931Z-5.0/LFT2 from Texas Instruments is a fixed-output 5.0 V low-dropout linear regulator in TO-92 package, delivering ≥100 mA output current with ≤0.6 V input-output differential at 100 mA and reverse battery protection up to −50 V. It operates across −40°C to +85°C and supports automotive memory standby and low-power microcontroller supply applications.

For engineers reviewing the LM2931Z-5.0/LFT2 datasheet, LM2931Z-5.0/LFT2 pinout, LM2931Z-5.0/LFT2 application, or LM2931Z-5.0/LFT2 equivalent, key selection criteria include dropout voltage at 100 mA, quiescent current under light load, reverse transient tolerance, and TO-92 thermal performance in space-constrained designs.

Technical Context

The LM2931Z-5.0/LFT2 implements an internal PNP pass transistor architecture enabling ultra-low dropout (0.3 V max at 100 mA) and sub-1 mA quiescent current at 10 mA load. Its integrated protection includes reverse battery (-50 V transient), 60 V load dump shutdown, short-circuit limiting, and thermal overload cutoff.

Unlike standard LDOs, it features mirror-image insertion immunity and requires a minimum 100 μF output capacitor for stability-ESR sensitivity mandates careful capacitor selection per temperature and load conditions.

Key Specifications

Pinout & Package

LM2931Z-5.0/LFT2 uses the TO-92 plastic package (3-pin, vertical mounting), with pin 1 = Input, pin 2 = Ground, pin 3 = Output. Thermal resistance θ_JA = 195°C/W limits continuous dissipation to ~350 mW at 25°C ambient without heatsinking.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar low-dropout linear regulator applications.

Compared with LM2931T-5.0/NOPB, LM2931Z-5.0/LFT2 trades thermal capability for compactness and mechanical compatibility with legacy TO-92 footprints; versus TLV70550DBVR, it sacrifices quiescent current efficiency for integrated automotive-grade protection-making it uniquely suited for cost-sensitive, space-constrained, and ruggedized 5 V regulation.

Availability

LM2931Z-5.0/LFT2 is available at Aetrix Electronics and suitable for automotive memory backup, industrial sensor nodes, POS peripheral supplies, and legacy controller I/O requiring stable component supply across extended product lifecycles.

Supply support for LM2931Z-5.0/LFT2 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 specializing in analog and embedded processing technologies, with decades of automotive and industrial qualification expertise.

The LM2931-N series was designed specifically for automotive and industrial standby power systems-emphasizing fault resilience, low quiescent current, and wide-input tolerance in compact packages.

FAQ

What is the maximum input voltage for LM2931Z-5.0/LFT2?

The absolute maximum input voltage for LM2931Z-5.0/LFT2 is 26 V DC under normal operating conditions. During line transients such as automotive load dumps, it withstands up to 60 V for 1 ms before entering protective shutdown-ensuring robustness without external clamping components.

Does LM2931Z-5.0/LFT2 require an output capacitor, and what value is recommended?

Yes, LM2931Z-5.0/LFT2 requires a minimum 100 μF output capacitor for stability. Aluminum or tantalum electrolytics are recommended; ESR must be < 1 Ω. For applications operating only above 25°C or delivering ≤10 mA, 47 μF may suffice-but full-spec 100 μF is advised for guaranteed performance across −40°C to +85°C.

Is LM2931Z-5.0/LFT2 pin-compatible with standard 78L05 regulators?

Yes, LM2931Z-5.0/LFT2 uses the same TO-92 pinout (Input-Ground-Output) as 78L05, enabling direct mechanical replacement. However, its lower dropout (0.6 V vs. 1.7 V) and integrated protections allow operation at lower input voltages and harsher environments where 78L05 would fail.

What protection features does LM2931Z-5.0/LFT2 include?

LM2931Z-5.0/LFT2 integrates reverse battery protection (−50 V transient), 60 V load dump shutdown, short-circuit current limiting, internal thermal overload protection, and mirror-image insertion immunity-eliminating the need for external diodes, TVS devices, or fuses in most automotive and industrial implementations.

Can LM2931Z-5.0/LFT2 be used in battery-powered applications with long standby life?

Yes, LM2931Z-5.0/LFT2 draws only 1.0 mA maximum quiescent current at 10 mA load, and as low as 0.4 mA typical-making it ideal for battery-backed RTCs, security sensors, and metering devices where multi-year operation from primary cells is required.