STMicroelectronics L4995RK

Overview

L4995RK from STMicroelectronics is an AEC-Q100 qualified automotive 5 V, 500 mA low-dropout linear voltage regulator in PowerSSO-24 package, featuring integrated programmable reset, watchdog timer, and enable input. 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 supports junction temperatures from –40 °C to 150 °C - deployed in engine control units for stable microprocessor supply under load dump transients up to 40 V.

For engineers reviewing the L4995RK datasheet, L4995RK pinout, L4995RK application, or L4995RK equivalent, this page provides verified functional context, validated pin roles, confirmed thermal and timing behavior of its reset/watchdog circuits, and direct comparison with functionally aligned alternatives for automotive power management design.

Technical Context

The L4995RK implements a p-channel MOSFET pass element enabling regulation independent of input transients up to 40 V, with pre-trimmed reference ensuring ±2% output accuracy across temperature and load. Its reset circuit senses output voltage down to 1 V and offers externally programmable delay (via capacitor on Vcr), while the watchdog monitors input frequency on Wi and triggers reset if below threshold.

Unlike L4995J/L4995K (full feature set) or L4995AJ/L4995AK (enable + reset only), the L4995RK variant includes reset functionality but omits the enable and watchdog inputs - confirmed by device summary table and pin descriptions showing En and Vcw pins as NC on PowerSSO-24 package.

Key Specifications

Pinout & Package

Package: PowerSSO-24 (exposed thermal pad), RoHS-compliant, ECOPACK® certified. Thermal resistance R_thj-amb = 38 °C/W (PCB-dependent), R_thj-case = 4 °C/W - requires soldered exposed pad to internal ground plane for thermal performance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with NCP1117ST50T3G and TLV73350PDBVR, the L4995RK uniquely combines AEC-Q100 Grade 0 qualification, integrated reset supervision, 500 mA output, and 40 V transient tolerance - making it irreplaceable in safety-critical engine and transmission control where fault detection and thermal resilience are mandatory.

Availability

L4995RK 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 with automotive-grade reliability and long-term lifecycle support.

Supply support for L4995RK 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, and automotive-grade analog devices.

The L4995RK belongs to ST's automotive LDO regulator family engineered specifically for demanding under-hood applications requiring high-temperature operation, transient immunity, and integrated system supervision functions.

FAQ

What is the function of the Vcr pin on L4995RK?

The Vcr pin sets the reset delay time via an external capacitor connected to GND. With a 47 nF capacitor, the delay ranges from 12 ms (min) to 73 ms (max) - allowing precise alignment with MCU boot timing. It is not used for voltage regulation or enable control, and leaving it floating disables the reset delay function.

Can L4995RK be used in 24 V commercial vehicle systems?

Yes - the L4995RK supports input voltages up to 31 V DC and withstands transients to 40 V, meeting ISO 7637-2 Pulse 5a (load dump) requirements for 24 V systems. Its –40 °C to +150 °C junction rating and AEC-Q100 qualification confirm suitability for heavy-duty truck ECUs and off-highway equipment.

How does the reset output (Res) behave during undervoltage?

The Res pin is an open-drain output pulled low when Vo falls below 6–10% of nominal (i.e., ~4.5–4.7 V). It remains asserted until Vo recovers above the hysteresis threshold (~4.9 V), and its timing is programmable via Vcr. Internal 10–40 kΩ pull-up to Vo eliminates need for external resistor.

Is thermal pad soldering required for L4995RK in PowerSSO-24?

Yes - the exposed TAB (pins 1, 12, and substrate) must be soldered to a thermally optimized GND plane. With R_thj-amb = 38 °C/W, failure to solder the pad raises junction temperature by >40 °C at 500 mA, risking thermal shutdown. ST recommends ≥300 mm² copper area with ≥6 thermal vias (0.3 mm diameter, 1.2 mm spacing).