STMicroelectronics L4993DTR

Overview

L4993DTR from STMicroelectronics is an AEC-Q100 qualified automotive 5 V low-dropout linear voltage regulator with integrated reset and watchdog functions. It delivers up to 150 mA output current, features 400 mV max dropout at 150 mA, ±2% output voltage tolerance, and operates across 5.6 V–31 V input range - designed for microprocessor power supply in engine control units (ECUs) and body electronics.

For engineers reviewing the L4993DTR datasheet, L4993DTR pinout, L4993DTR application, or L4993DTR equivalent, key selection criteria include its programmable reset delay (via external capacitor on Vcr), watchdog timer adjustability (via Vcw), thermal shutdown at 150°C, wide junction temperature range (−40°C to +150°C), and SO-8 package compatibility with automotive PCB thermal constraints.

Technical Context

The L4993DTR integrates a p-channel MOSFET pass element enabling regulation down to 400 mV dropout while maintaining stable 5 V output under input transients up to 40 V. Its internal pre-trimmed reference ensures ±2% output accuracy across −40°C to +150°C junction temperature.

Reset functionality monitors output voltage down to 1 V threshold (Vo_th = 6–10% below nominal), with programmable delay (65–150 ms for 1 nF); watchdog detects low-frequency pulses on Wi pin and triggers reset when timeout occurs, both configurable via external RC networks on Vcr and Vcw pins.

Key Specifications

Pinout & Package

Package: SO-8 (Small Outline, 8-pin, surface-mount). Thermal pad on exposed underside connected to Gnd for enhanced heat dissipation in automotive PCB layouts.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar automotive LDO-with-supervision applications.

Compared with TLV70733PDRVR and MAX6715AATA+T, the L4993DTR uniquely combines AEC-Q100 Grade 0 qualification, integrated reset + watchdog, and 150°C operation in SO-8 - delivering complete power supervision in a single automotive-grade package without design compromises.

Availability

L4993DTR is available at Aetrix Electronics and suitable for engine control units (ECUs), body control modules (BCMs), and advanced driver assistance system (ADAS) camera ECUs requiring stable component supply with automotive-grade reliability and long-term lifecycle support.

Supply support for L4993DTR 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 specializing in automotive, industrial, and power management solutions, with over 40 years of analog IC innovation.

The L4993DTR belongs to ST's automotive power management portfolio, engineered specifically for fault-tolerant microprocessor power delivery in harsh under-hood environments where voltage supervision and thermal resilience are mandatory.

FAQ

What is the minimum input voltage required for regulation?

The L4993DTR maintains regulation down to 5.6 V input across its full operating temperature range. Below this, output voltage drops proportionally with input; the device remains functional but does not guarantee 5 V output. This threshold ensures compatibility with degraded 12 V battery conditions during cranking.

Can the reset output drive a microcontroller's NRST pin directly?

Yes - the open-drain Res pin has an internal 12–50 kΩ pull-up to Vos and can sink ≥1 mA at 0.4 V. It interfaces directly with standard CMOS NRST inputs; no external pull-up is needed unless longer trace capacitance demands faster rise time.

How does the watchdog interact with the reset function?

Both reset sources - undervoltage and watchdog timeout - assert the same Res pin low. The watchdog only activates when WEn is high; its timeout event is electrically identical to a voltage-based reset, simplifying host MCU fault-handling firmware.

Is the SO-8 package thermally adequate for 150 mA continuous load?

Yes - with a 2 cm² copper pour on FR4 (2 mm thick, 35 µm Cu), the SO-8 achieves R_th-jamb = 130°C/W. At 150 mA and 13.5 V input, power dissipation is ~1.275 W, resulting in ~166°C junction rise - within the 150°C thermal shutdown limit only with proper heatsinking. Derating or airflow is recommended for sustained full-load operation.