STMicroelectronics L4988MDTR

Overview

L4988MDTR from STMicroelectronics is an AEC-Q100 qualified automotive 5V low-dropout linear 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 core logic and peripheral rails in engine control units.

For engineers reviewing the L4988MDTR datasheet, L4988MDTR pinout, L4988MDTR application, or L4988MDTR equivalent, key selection criteria include its programmable reset delay (via external capacitor on Vcr), adjustable watchdog timeout (via Vcw), thermal shutdown at 150°C, enable-controlled watchdog activation, and SO-20 package suitability for high-reliability under-hood environments.

Technical Context

The L4988MDTR integrates a p-channel MOSFET pass element enabling regulation down to 500mV dropout at full 200mA load while maintaining stability against input transients up to 40V. Its pre-trimmed bandgap reference ensures ±2% output accuracy over −40°C to +150°C junction temperature.

Reset functionality monitors Vo with a user-configurable threshold (6–10% below 5V) and delay (e.g., 150ms with 1nF), while the watchdog circuit responds to missing pulses on Wi by asserting Res low - both features are gated by the WEn pin and use internal charge/discharge currents (8–30µA) to set timing via external capacitors on Vcr and Vcw.

Key Specifications

Pinout & Package

Package: SO-20 (16+2+2 lead count, thermally enhanced layout with 4 dedicated GND pins for heat spreading).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TL35584QKVQ1 and MAX25210ATPA/VY+, the L4988MDTR offers pin-strapped timing flexibility without serial interface overhead, lower quiescent current in watchdog-off mode, and SO-20 thermal performance optimized for conduction-cooled automotive PCB layouts - making it optimal for cost-sensitive, high-volume ECU designs where analog configurability is preferred.

Availability

L4988MDTR 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 extended temperature and automotive lifecycle demands.

Supply support for L4988MDTR 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 ICs, with manufacturing and design centers across Europe, Asia, and the Americas.

The L4988MDTR belongs to ST's automotive-grade linear regulator family, engineered specifically for functional-safety-aware power domains in engine, chassis, and ADAS systems where reliability under extreme thermal and electrical stress is non-negotiable.

FAQ

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

The L4988MDTR maintains 5V regulation down to 5.6V input at 200mA load, corresponding to a maximum dropout of 500mV. Below 5.6V, output voltage follows input minus dropout until regulation is lost - verified per DS5334 Rev 8 Table 5, Vdp test condition at Io = 200mA.

How is the reset delay time calculated using the Vcr capacitor?

Reset delay trd = 512 × Tosc, where Tosc = [(Vrhth − Vrlth) × Ctr] / Icr + [(Vrhth − Vrlth) × Ctr] / Idr. With Vrhth ≈ 2.35V, Vrlth ≈ 0.65V, Icr/Idr ≈ 17.6µA (typ), and Ctr = 1nF, trd ≈ 150ms - values confirmed in Table 6 and Figure 26 of the official datasheet.

Can the watchdog function operate independently of the reset circuit?

Yes - the watchdog monitors Wi pulses and asserts Res low on timeout regardless of Vo level, provided WEn is high. Reset remains active only when Vo falls below Vo_th (6–10% below 5V). Both functions share the same Res output pin but are triggered by independent internal comparators and timers.

Is the SO-20 package thermally compatible with standard FR4 PCBs without metal-core substrates?

Yes - with 6 cm² of 2-oz copper pour connected to all four GND pins, the SO-20 achieves Rth-jamb = 51°C/W (DS5334 Rev 8 Table 4), enabling 200mA continuous operation at 150°C junction temperature in free-air conditions - validated in Figure 33 and Section 4.2.