STMicroelectronics L4988MD

Overview

L4988MD from STMicroelectronics is an AEC-Q100 qualified automotive 5V low-dropout voltage regulator with integrated reset and watchdog functions, delivering up to 200mA output current, 500mV max dropout at 200mA, ±2% output voltage tolerance, and operation across 5.6V–31V input range - used to power microcontroller cores and safety-critical ECUs in engine control units.

For engineers reviewing the L4988MD datasheet, L4988MD pinout, L4988MD application, or L4988MD equivalent, key selection criteria include its programmable reset delay (via external capacitor on Vcr), adjustable watchdog timeout (via Vcw), thermal shutdown at 150°C, wide junction temperature range (−40°C to +150°C), and SO-20 package with multiple ground pins for thermal management.

Technical Context

The L4988MD implements a p-channel MOSFET pass element enabling low-dropout regulation independent of input transients up to 40V. Its internal pre-trimmed reference ensures ±2% output accuracy without external trimming components.

Reset supervision monitors Vo down to 1V with user-configurable delay (trd = 512 × Tosc) via external capacitor on Vcr; watchdog functionality uses Wi input frequency detection and Vcw-timed timeout, both enabled/disabled via WEn pin - all operating within automotive-grade thermal and ESD robustness (±2kV HBM, 750V CDM).

Key Specifications

Pinout & Package

Package: SO-20 (16+2+2), thermally enhanced with four dedicated GND pins (pins 4, 15, 16, and shared GND function on pin 2) connected to internal heat spreader for R_th-jamb = 51°C/W (6 cm² copper area).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar automotive voltage regulator with supervisory functions applications.

Compared with NCP380LSN33T2G and TLE42754G, the L4988MD uniquely combines AEC-Q100 Grade 0 operation, programmable reset delay, and configurable watchdog in a single SO-20 package - making it the only choice for ASIL-B compliant MCU power domains requiring full diagnostic coverage and thermal resilience.

Availability

L4988MD is available at Aetrix Electronics and suitable for engine control units, body control modules, transmission control units, and ADAS camera ECUs requiring stable component supply across automotive production lifecycles.

Supply support for L4988MD 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 broad portfolio of AEC-Q100-qualified analog and power ICs.

The L4988MD belongs to ST's automotive voltage regulator family designed specifically for functional safety-critical power domains in powertrain and chassis systems - emphasizing integrated diagnostics, thermal robustness, and long-term supply assurance.

FAQ

What is the minimum input voltage required for regulation at full 200mA load?

The L4988MD maintains regulation down to 5.6V input across its full operating temperature range. At 200mA load and 25°C, the dropout voltage is typically 270mV, meaning Vo remains stable as long as Vs ≥ 5.27V - but the absolute minimum specified input is 5.6V to guarantee performance across −40°C to +150°C junction temperature.

Can the reset output (Res) drive a standard MCU reset pin directly?

Yes. The Res pin is an open-drain output with internal 12–50 kΩ pull-up to Vo, capable of sinking ≥10 mA. It asserts low when Vo falls below Vo_th (6–10% below 5V) or Wi pulses fail. No external pull-up is needed - direct connection to most MCU reset inputs (e.g., STM32, NXP S32K) is fully compatible.

How does the watchdog timer interact with the enable (WEn) pin?

When WEn is low, the entire watchdog circuit is disabled - Wi input is ignored, Vcw capacitor has no effect, and Res remains high regardless of Wi activity. When WEn is high, the watchdog monitors Wi edge rate; if the period exceeds Twop (set by Vcw capacitor), Res is pulled low. This allows hardware-controlled watchdog activation during runtime or safe boot sequences.

Is the SO-20 package of L4988MD lead-free and RoHS-compliant?

Yes. The L4988MD is manufactured in ST's ECOPACK®-compliant SO-20 package, meeting RoHS Directive 2011/65/EU and REACH SVHC requirements. Lead finish is matte tin, and the device is halogen-free per IEC 61249-2-21, with full material declarations available in ST's official product change notifications.