STMicroelectronics L4995KTR

Overview

L4995KTR from STMicroelectronics is an AEC-Q100-qualified automotive 5 V, 500 mA low-dropout linear voltage regulator in PowerSSO-24 package, featuring integrated watchdog timer, programmable reset delay, and enable input. It operates from 5.6 V to 31 V DC supply, delivers ±2% output voltage tolerance, maintains regulation under 40 V transients, and supports microprocessor power sequencing in engine control units and ADAS domain controllers.

For engineers reviewing the L4995KTR datasheet, L4995KTR pinout, L4995KTR application, or L4995KTR equivalent, key selection criteria include its 500 mV dropout at 400 mA, 3 µA quiescent current when disabled, -40 °C to 150 °C junction temperature range, and dual external capacitor programming for reset delay (Vcr) and watchdog period (Vcw).

Technical Context

The L4995KTR uses a p-channel MOSFET pass element enabling stable 5 V regulation across wide input voltage swings (5.6–31 V), with internal pre-trimmed reference ensuring ±2% output accuracy over temperature and load. Its architecture integrates three independent supervisory functions: reset circuit sensing output voltage down to 1 V, externally programmable reset pulse delay via Vcr pin capacitor, and watchdog timer triggered by Wi input frequency monitoring.

Thermal protection activates at 150 °C with 10 °C hysteresis, and short-circuit current limiting ranges from 550 mA to 1050 mA depending on input voltage. The PowerSSO-24 package provides 4 °K/W junction-to-case thermal resistance and supports high-power dissipation in constrained automotive PCB layouts.

Key Specifications

Pinout & Package

Package: PowerSSO-24 (exposed pad), thermally enhanced surface-mount package with 24 terminals and integrated heat slug for automotive under-hood thermal management.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLV73350PDBVR and TPS7B8133QDGNRQ1, the L4995KTR uniquely combines 500 mA 5 V regulation, AEC-Q100 Grade 0 rating, and dual-programmable supervisory functions in a thermally optimized PowerSSO-24 package-making it the only drop-in solution for ASIL-B compliant ECU power domains requiring coordinated reset and watchdog behavior.

Availability

L4995KTR is available at Aetrix Electronics and suitable for engine control units, ADAS domain controllers, body control modules, and infotainment head units requiring stable component supply across extended automotive temperature and lifetime requirements.

Supply support for L4995KTR 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 coverage from discrete devices to full-system ICs.

The L4995 family belongs to ST's automotive-grade power management product line, designed specifically to meet stringent ISO/TS 16949 and AEC-Q100 requirements for engine bay and chassis-mounted electronic control units.

FAQ

What is the minimum input voltage required for regulation at full 500 mA load?

The L4995KTR maintains 5 V regulation down to 5.6 V input at 500 mA load, with a maximum dropout voltage of 500 mV. At 400 mA, typical dropout is 270 mV, meaning regulation holds with as little as 5.27 V input. Below 5.6 V, output voltage drops proportionally per the dropout curve in Figure 7 of DS5053 Rev 15.

How does the watchdog timer interact with the reset output?

The watchdog monitors frequency at the Wi pin; if input pulses fall below the programmed timeout (set by Vcw capacitor), the Res pin is pulled low within 4–16 ms. This same Res signal is also asserted when Vo drops below the 6–10% undervoltage threshold. Both conditions share the same open-drain output and internal pull-up to Vo, enabling unified system reset signaling.

Can the L4995KTR be used without connecting the En pin?

Yes - the En pin can be tied directly to VS to permanently enable the device. However, doing so forfeits the ability to enter ultra-low-power shutdown mode (3 µA Iqn). For battery-sensitive applications like BCMs, leaving En unconnected is not recommended; instead, connect it to a system controller GPIO for active power gating.

What PCB layout practices are critical for thermal performance in PowerSSO-24?

Maximize copper area under the exposed TAB (Pins 1 and 12) using ≥3 cm² of 2 oz copper with ≥6 thermal vias (0.3 mm diameter, 1.2 mm spacing) connected to inner-layer ground planes. Per Section 4.2 of DS5053 Rev 15, this achieves Rthj-amb = 38 °K/W - essential for sustaining 500 mA at 150 °C junction temperature in sealed enclosures.