STMicroelectronics L4995RKTR

Overview

L4995RKTR from STMicroelectronics is an AEC-Q100 qualified automotive 5 V, 500 mA low-dropout linear voltage regulator with integrated programmable reset and watchdog timer functions. It operates from 5.6 V to 31 V DC input, delivers ±2% output voltage tolerance, maintains 500 mV max dropout at 400 mA, and features thermal shutdown, short-circuit protection, and operation up to 150 °C junction temperature - deployed in engine control units and body electronics for stable microprocessor supply.

For engineers reviewing the L4995RKTR datasheet, L4995RKTR pinout, L4995RKTR application, or L4995RKTR equivalent, key selection criteria include its PowerSSO-24 package, externally programmable reset delay (via Vcr capacitor), watchdog timing (via Vcw capacitor), and enable-controlled system-level power sequencing in harsh automotive environments.

Technical Context

The L4995RKTR implements a p-channel MOSFET pass element enabling regulation independent of input transients up to 40 V. Its precision output derives from a pre-trimmed reference voltage, ensuring 4.9–5.1 V output across load (0–500 mA) and temperature (−40 °C to +150 °C).

Reset functionality monitors regulated output down to 1 V and triggers on Vo falling below 6–10% of nominal; delay is set by external capacitor on Vcr (12–73 ms typical with 47 nF). Watchdog timing is similarly capacitor-programmable on Vcw (20–80 ms period), with dedicated Wi input accepting pulse trains to prevent reset assertion.

Key Specifications

Pinout & Package

Package: PowerSSO-24 (exposed thermal pad), RoHS-compliant, ECOPACK® certified, designed for high-power dissipation in automotive PCBs with thermal vias and copper pour.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLV73350PDBVR and NCP1117ST50T3G, the L4995RKTR uniquely integrates AEC-Q100 compliance, programmable reset/watchdog, and 500 mA delivery in a thermally optimized PowerSSO-24 package - making it the sole option for safety-critical, high-temperature, functionally supervised automotive domains.

Availability

L4995RKTR is available at Aetrix Electronics and suitable for engine control units, body control modules, ADAS sensors, and infotainment head units requiring stable component supply across automotive production lifecycles.

Supply support for L4995RKTR 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 silicon solutions for automotive, industrial, and power management applications.

The L4995 family belongs to ST's automotive-grade power management IC portfolio, engineered specifically to replace discrete reset/watchdog circuits and simplify robust, ASIL-ready power architecture in modern vehicles.

FAQ

What is the maximum allowable input voltage for continuous operation?

The L4995RKTR supports continuous DC input from 5.6 V to 31 V. Its absolute maximum rating is 40 V, which covers automotive load-dump transients per ISO 7637-2 Pulse 5a, but sustained operation above 31 V risks thermal overload and is not recommended.

How does the reset function behave during cold-crank conditions?

During cold-crank (input dropping to ~5.6 V), the L4995RKTR maintains regulation and asserts reset only if output falls below 6–10% of 5 V (i.e., ~4.5–4.7 V). Its 1 V minimum sensing threshold ensures reliable brownout detection even with degraded output, and reset delay remains programmable via Vcr capacitor.

Can the watchdog timer be disabled while retaining reset functionality?

Yes. The watchdog is only active when the Wi input receives valid pulses; leaving Wi floating or held low disables watchdog action. Reset remains fully functional via Vo sensing and Vcr programming, as these circuits operate independently of Wi activity.

Is the exposed thermal pad electrically isolated from internal circuitry?

No. The TAB (exposed pad) connects internally to GND and must be soldered to the PCB ground plane. Electrical isolation is not provided; doing so would compromise thermal performance, EMI shielding, and functional grounding required for automotive EMC compliance.