STMicroelectronics LM2931AD50

Overview

LM2931AD50 from STMicroelectronics is a fixed 5.0 V, very low-dropout linear regulator in DPAK package, delivering up to 100 mA output current with 90 mV typical dropout at 10 mA and 2.5 mA typical quiescent current at full load. It features integrated load dump protection (60 V transient), reverse polarity protection (−50 V), thermal/current limiting, and AEC-Q100 qualification-designed for automotive body control modules and battery-powered infotainment power rails.

For engineers reviewing the LM2931AD50 datasheet, LM2931AD50 pinout, LM2931AD50 application, or LM2931AD50 equivalent, key selection criteria include its 5.0 V ±2.5% output accuracy over −40 to 125 °C, 75 dB supply voltage rejection at 120 Hz, and inhibit-controlled shutdown capability in SO-8 variants-critical for low-power standby modes in automotive ECUs.

Technical Context

The LM2931AD50 employs a PNP pass transistor architecture enabling ultra-low dropout operation, with internal feedback loop compensation optimized for stability with 100 µF output capacitance. Its inhibit input (VINH) enables logic-level shutdown, reducing quiescent current to ≤1 µA in OFF mode when VINH > 3.25 V.

Transient protection is implemented via internal clamp circuitry that activates during load dump events (≤60 V, <100 ms) or reverse battery conditions (≤−50 V), automatically disabling regulation to safeguard both IC and downstream circuitry without external components.

Key Specifications

Pinout & Package

DPAK package (TO-252-3) with exposed thermal pad for enhanced heat dissipation; R_thJA = 100 °C/W on standard PCB, R_thJC = 8 °C/W to case.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar fixed-output LDO regulator applications.

Compared with TLV73350PDBVR and TPS7B6750QPWPRQ1, the LM2931AD50 uniquely balances automotive-grade transient protection, low dropout, and cost-effective DPAK packaging-making it optimal for non-safety-critical but ruggedized body electronics where reliability trumps ultra-low I_Q or extreme temperature range.

Availability

LM2931AD50 is available at Aetrix Electronics and suitable for automotive body control modules, infotainment standby power, and telematics GPS receivers requiring stable component supply with AEC-Q100 traceability and long-term production continuity.

Supply support for LM2931AD50 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, specializing in automotive, industrial, and power management ICs with broad manufacturing and quality certification coverage.

The LM2931 series belongs to ST's automotive-qualified linear regulator product line, engineered specifically for robust, low-noise local regulation in 12 V vehicle electrical systems-including body electronics, lighting, and connectivity modules.

FAQ

What is the minimum input voltage required for regulation at full 100 mA load?

The LM2931AD50 maintains regulation when input voltage exceeds output voltage plus dropout. At 100 mA, maximum dropout is 600 mV, so minimum VIN is 5.0 V + 0.6 V = 5.6 V. Below this, output collapses linearly with input-verified per Table 4 dropout voltage specs at IO = 100 mA.

Does the DPAK variant include inhibit functionality?

No. The inhibit control (VINH) is only available on the SO-8 package variant (e.g., LM2931CD50). The LM2931AD50 in DPAK has three pins (VIN, GND, VOUT) and operates continuously when powered-confirmed by Figure 2 pin configuration and DS1760 Rev 24 Section 2.

Can LM2931AD50 replace older 78L05 regulators in existing designs?

Yes, with caveats: it matches 78L05's 5 V output and TO-92 footprint compatibility, but LM2931AD50 in DPAK requires PCB layout change. Its lower dropout (90 mV vs ~1.7 V) improves efficiency at low VIN, and built-in protection eliminates external diodes-validated in automotive replacement studies per ST AN4423.

What thermal derating applies at 100 mA continuous load in still air?

Using R_thJA = 100 °C/W (DPAK, standard PCB), power dissipation at 100 mA and 14 V input is (14 − 5) × 0.1 = 0.9 W, causing ΔT = 90 °C above ambient. With max T_J = 125 °C, max ambient is 35 °C unless heatsinking is added-per Table 2 thermal data and absolute maximum ratings on page 4 of DS1760.