STMicroelectronics L4979D013TR

Overview

L4979D013TR from STMicroelectronics is an AEC-Q100 qualified automotive low-dropout linear voltage regulator with integrated reset and watchdog functions. It delivers a precise 5.0 V ±2% output at up to 150 mA, operates from 5.6 V to 31 V input, achieves <400 mV dropout at full load, and features programmable reset delay (via external capacitor on Vcr) and watchdog timeout (via Vcw). It is used in engine control units (ECUs) for stable microcontroller power and fault monitoring.

For engineers reviewing the L4979D013TR datasheet, L4979D013TR pinout, L4979D013TR application, or L4979D013TR equivalent, key selection criteria include its automotive-grade thermal range (−40 °C to 150 °C), 6 µA quiescent current in disable mode, reset threshold tracking 6–10% below Vo_ref, and SO-8 package compatibility with board-level thermal management requirements.

Technical Context

The L4979D013TR integrates three tightly coupled subsystems: a p-channel MOSFET-based LDO regulator with internal trimming for ±2% output accuracy across temperature and load; a voltage-monitoring reset circuit that asserts RES low when Vo drops below 4.5–4.7 V (6–10% below 5.0 V nominal) with programmable delay via Vcr capacitor; and a windowed watchdog timer that monitors Wi pulse frequency and triggers RES if the Vcw capacitor discharge exceeds the low-threshold (0.5–0.8 V) before recharge.

Its enable input (EN) controls global operation: high enables regulation, reset, and watchdog; low reduces quiescent current to 6 µA and disables all outputs. Thermal shutdown activates at 150 °C junction temperature with 10 °C hysteresis, and short-circuit protection limits output current to 150–500 mA depending on conditions.

Key Specifications

Pinout & Package

Package: SO-8 (GAPGCFT00199), ECOPACK® compliant, surface-mount, 8-pin small outline with exposed thermal pad (pins 5/6/15/16 in SO-20 variant are GND for heat spreading; SO-8 uses pins 2, 3, 8, and 9 as GND).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar automotive LDO + supervisor applications.

Compared with TLV70750PDBVR and MAX6723SKA36+T, the L4979D013TR uniquely integrates regulation, reset, and watchdog in one SO-8 package with automotive thermal and qualification specs-eliminating inter-IC timing skew, reducing component count, and simplifying layout for functional-safety-compliant systems.

Availability

L4979D013TR is available at Aetrix Electronics and suitable for engine control units, body control modules, ADAS camera ECUs, and transmission control units requiring stable component supply across extended automotive temperature and lifetime requirements.

Supply support for L4979D013TR 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 microcontrollers, power management ICs, sensors, and automotive-grade analog devices.

The L4979 series belongs to ST's automotive power management portfolio, engineered specifically for single-chip power and supervision in engine, chassis, and body electronics where AEC-Q100 compliance and functional safety readiness are mandatory.

FAQ

What is the maximum input voltage the L4979D013TR can withstand?

The absolute maximum DC supply voltage is 40 V, as specified in Table 3 of the datasheet. Operation is guaranteed from 5.6 V to 31 V, but the device survives transient overvoltages up to 40 V without damage-critical for handling automotive load-dump events.

How does the reset output behave when the output voltage falls below 1 V?

The RES output remains asserted low down to Vo = 1 V, with reaction time decreasing to 2 µs below 4 V (per Table 7 footnote). Below 1 V, the reset circuit is no longer guaranteed to operate, but thermal shutdown and short-circuit protection remain active to prevent damage.

Can the watchdog timer be disabled while keeping the regulator active?

No-the EN pin enables or disables the entire device: regulator, reset, and watchdog simultaneously. There is no independent watchdog disable function. To suppress watchdog action, the host MCU must maintain valid Wi pulses or tie Wi to a stable logic level within spec (Vil ≤ 1.5 V or Vih ≥ 3.5 V).

Is the L4979D013TR pin-compatible with other variants in the L4979 family?

No-L4979D013TR is the SO-8 version (order code suffix "D"), while L4979MD is SO-20. Pin functions differ significantly: SO-8 has 8 pins with shared GND roles, whereas SO-20 spreads GND, RES, and timing pins across 20 positions. Layout and footprint are not interchangeable.