STMicroelectronics LM2931AD33R

Overview

LM2931AD33R from STMicroelectronics is a fixed 3.3 V, 100 mA low-dropout linear regulator in DPAK package, featuring 90 mV typical dropout at 10 mA, 2.5 mA quiescent current at 100 mA load, and AEC-Q100 qualification for automotive use. It integrates load dump protection up to 60 V, reverse transient protection to −50 V, and thermal/current limiting - deployed as local power supply in engine control units, body electronics, and infotainment subsystems.

For engineers reviewing the LM2931AD33R datasheet, LM2931AD33R pinout, LM2931AD33R application, or LM2931AD33R equivalent, key selection criteria include dropout voltage under 100 mA load, shutdown logic compatibility with L78L-family footprints, thermal resistance (R_thJC = 8 °C/W), and transient survivability during battery jump-start or load dump events.

Technical Context

The LM2931AD33R employs a PNP pass transistor architecture enabling ultra-low dropout operation, with internal feedback loop stabilized for CO ≥ 100 µF and CI = 0.1 µF. Its inhibit input (VINH) enables logic-controlled shutdown, reducing quiescent current to 0.3–1 mA in OFF mode while maintaining reverse polarity tolerance down to −50 V for 100 ms.

Designed for automotive environments, it operates across −40 to +125 °C junction temperature, withstands 60 V positive transients and −50 V reverse transients, and delivers ±3.5% output voltage accuracy over full load/temperature range - meeting ISO 7637-2 pulse 5a requirements without external clamping.

Key Specifications

Pinout & Package

DPAK package (TO-252-3) with exposed thermal pad; thermally optimized for PCB copper pour mounting per ST's recommended footprint (FP_0068772_25).

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM2931CD33R, the LM2931AD33R adds AEC-Q100 qualification and guaranteed −50 V reverse transient survival; versus TLV73333PDBVR, it trades higher IQ for robustness in harsh automotive electrical environments - making it irreplaceable where ISO 16750-2 compliance is mandatory.

Availability

LM2931AD33R is available at Aetrix Electronics and suitable for automotive ECU design, body electronics development, and telematics hardware integration requiring stable component supply across extended temperature and transient conditions.

Supply support for LM2931AD33R 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 silicon solutions for automotive, industrial, and consumer markets since 1987.

The LM2931 series belongs to ST's automotive-grade linear regulator product line, engineered specifically for robustness in vehicle electrical systems - emphasizing transient immunity, wide temperature operation, and functional safety readiness.

FAQ

What is the maximum input voltage the LM2931AD33R can handle continuously?

The LM2931AD33R has a maximum continuous operating input voltage of 26 V, as specified in Table 3 of DS1760 Rev 24. This rating applies across the full −40 to +125 °C junction temperature range with 10 mA load. Exceeding 26 V triggers automatic shutdown during transients up to 60 V, but sustained operation above 26 V is not permitted.

Does the LM2931AD33R require an external capacitor on the inhibit pin?

No external capacitor is required on the inhibit (VINH) pin. The device accepts standard TTL/CMOS logic levels: VINH ≤ 1.2 V enables regulation, while VINH ≥ 3.25 V disables it. Input current remains low (22–50 µA at 2.5 V), so direct connection to a microcontroller GPIO suffices without filtering or pull-up/down components.

Can the LM2931AD33R be used without the recommended 100 µF output capacitor?

No - the 100 µF output capacitor (CO) is mandatory for stability, as confirmed in Figure 3 (Application Circuit) and Figure 20 (Stability vs CO) of DS1760 Rev 24. Using less than 100 µF risks oscillation, especially with ESR < 100 mΩ. ST specifies CO ≥ 100 µF with 10–100 mΩ ESR for guaranteed phase margin across all operating conditions.

Is the DPAK package of LM2931AD33R lead-free and RoHS compliant?

Yes - the LM2931AD33R DPAK package is manufactured per ST's ECOPACK® environmental program and complies with RoHS Directive 2011/65/EU and REACH Regulation (EC) No. 1907/2006. Full material declarations and compliance documentation are accessible via ST's official product page using order code LM2931AD33R.