STMicroelectronics LM2931D-R

Overview

LM2931D-R from STMicroelectronics is a fixed-output, automotive-grade low-dropout linear regulator with 3.3 V output, 100 mA current capability, 90 mV typical dropout at 10 mA, and AEC-Q100 qualification (DPAK package). It integrates inhibit control, load dump protection up to 60 V, and reverse transient protection down to –50 V, making it suitable for engine control units and body electronics in 12 V automotive systems.

For engineers reviewing the LM2931D-R datasheet, LM2931D-R pinout, LM2931D-R application, or LM2931D-R equivalent, key selection criteria include dropout voltage under light/heavy load, quiescent current in ON/OFF modes, thermal resistance (R_thJA = 100 °C/W for DPAK), and transient survivability during battery jump-starts or load dumps.

Technical Context

The LM2931D-R employs a PNP pass transistor architecture enabling ultra-low dropout operation, with internal current limiting and thermal shutdown ensuring robustness under fault conditions. Its inhibit input (VINH) enables logic-controlled shutdown, reducing system standby power when paired with microcontroller GPIO.

Designed for harsh automotive environments, it withstands reverse battery connection (–15 V continuous, –50 V transient) and load dump surges (60 V, <100 ms), automatically entering safe shutdown without external protection circuitry. The device operates across –40 °C to +125 °C junction temperature with guaranteed output regulation over full input range (6–26 V).

Key Specifications

Pinout & Package

DPAK package (TO-252-3) with exposed thermal pad; compact surface-mount footprint optimized for automotive PCB space constraints and thermal performance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLV73333PDBVR and TPS7B6733QPWPRQ1, the LM2931D-R uniquely balances automotive transient robustness, ultra-low dropout, and inhibit control in a cost-optimized DPAK package - ideal for volume automotive modules where reliability and simplicity are prioritized over safety certification or ultra-low I_Q.

Availability

LM2931D-R is available at Aetrix Electronics and suitable for engine control units, body control modules, ADAS cameras, and infotainment subsystems requiring stable component supply across automotive production lifecycles.

Supply support for LM2931D-R 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 vertical manufacturing capabilities.

The LM2931 product line delivers rugged, pin-compatible LDO regulators for automotive subsystems, designed specifically to replace legacy 78L-series devices while adding transient protection and logic control - targeting cost-sensitive, high-reliability vehicle electronics.

FAQ

What is the maximum continuous input voltage for LM2931D-R?

The LM2931D-R has a maximum continuous operating input voltage of 26 V, as specified in Table 3 of DS1760 Rev 24. It is rated for 60 V transient input (≤100 ms) and –50 V reverse transient, but sustained operation above 26 V risks permanent damage. Input filtering and clamping are unnecessary due to built-in protection.

Does LM2931D-R require an external bypass capacitor on the inhibit pin?

No external capacitor is required on the inhibit (VINH) pin. The datasheet specifies VINH logic thresholds (VIL ≤1.2 V, VIH ≥3.25 V) and input current (22–50 µA at 2.5 V), indicating direct GPIO interfacing is sufficient. Adding capacitance may slow response and is not recommended unless intentional debouncing is needed.

Can LM2931D-R be used without the output capacitor?

No. The LM2931D-R requires a minimum 100 µF output capacitor (aluminum or tantalum, ESR 0.1–1 Ω) as specified in Figure 3 and Section 4 of DS1760. Omitting it causes instability, oscillation, and potential thermal runaway. Ceramic capacitors alone are insufficient due to low ESR; a series resistor or hybrid solution is mandatory if ceramics are used.

Is the DPAK package of LM2931D-R lead-free and RoHS compliant?

Yes. Per Section 7 of DS1760 Rev 24, the LM2931D-R in DPAK is offered in ECOPACK®2-compliant packaging, meeting RoHS Directive 2011/65/EU and JEDEC JS-001 ESD standards. The device carries the "E2" marking on the package body and is halogen-free per IEC 61249-2-21.