STMicroelectronics L4995RJ

Overview

L4995RJ from STMicroelectronics is an AEC-Q100 qualified automotive 5 V, 500 mA low-dropout linear voltage regulator with integrated programmable reset circuit, thermal shutdown, and short-circuit protection. It operates from 5.6 V to 31 V DC input, delivers ±2% output voltage tolerance, maintains regulation under 40 V transients, and supports junction temperatures from –40 °C to 150 °C - deployed in engine control units and body electronics for stable microprocessor supply.

For engineers reviewing the L4995RJ datasheet, L4995RJ pinout, L4995RJ application, or L4995RJ equivalent, key selection considerations include its PowerSSO-12 package, externally programmable reset delay (via capacitor on Vcr), 500 mV dropout at 400 mA, 3 µA quiescent current when disabled, and absence of watchdog or enable functionality compared to L4995J/L4995AJ variants.

Technical Context

The L4995RJ implements a p-channel MOSFET pass element enabling low-dropout operation and immunity to input transients up to 40 V. Regulation relies on a pre-trimmed bandgap reference, achieving ±2% output accuracy across temperature and load. Its reset function monitors output voltage down to 1 V and triggers a programmable delay (12–73 ms with 47 nF) before asserting the open-drain Res pin.

No enable or watchdog circuitry is present - unlike L4995J or L4995AJ - making it a dedicated reset-enhanced LDO for cost-optimized automotive subsystems where independent reset timing is required but system-level supervision is handled externally. The device integrates thermal shutdown with 150 °C trip point and 10 °C hysteresis.

Key Specifications

Pinout & Package

Package: PowerSSO-12 (exposed pad), thermally enhanced surface-mount package with integrated heatsink via exposed substrate tab.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 5 V automotive LDO applications.

Compared with NCP1117ST50T3G and TLV73350PDBVR, the L4995RJ uniquely combines AEC-Q100 Grade 0 compliance, integrated reset with programmable delay, and 500 mA capability in a thermally robust PowerSSO-12 package - making it the only drop-in solution for reset-critical under-hood applications.

Availability

L4995RJ is available at Aetrix Electronics and suitable for engine control units, body control modules, ADAS camera ECUs, and infotainment power sequencing requiring stable component supply across automotive production lifecycles.

Supply support for L4995RJ 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 L4995RJ belongs to ST's automotive-grade linear regulator family designed specifically for robust, feature-integrated power supply in harsh-temperature vehicle subsystems - emphasizing reliability, functional safety readiness, and simplified system design.

FAQ

Is the L4995RJ pin-compatible with L4995J or L4995AJ?

No. While all share the PowerSSO-12 package, L4995RJ lacks En and Vcw pins used by L4995J/L4995AJ for enable and watchdog functions. Pin 1 (En) and Pin 7 (Vcw) are NC on L4995RJ, and Pin 9 (Wi) is unconnected. Direct replacement requires schematic revision to remove unused signals and verify reset-only functionality meets system requirements.

What is the minimum capacitor value required on the Vcr pin for reliable reset delay?

A 10 nF capacitor on Vcr yields ~2.5 ms typical delay; ST specifies 47 nF for 12–73 ms range. Values below 1 nF risk insufficient timing margin due to leakage and process variation. Always use X7R or C0G dielectric capacitors rated for ≥16 V to ensure stability across temperature and bias.

Can the Res output drive a microcontroller reset pin directly?

Yes. The Res pin is open-drain with internal 10–40 kΩ pull-up to Vo, compatible with standard CMOS reset inputs. For MCUs requiring active-high reset, add an external pull-up to Vcc and invert logic in firmware, or use a single-transistor inverter. No series resistor is needed unless ESD protection is added separately.

Does L4995RJ support reverse-battery protection?

No. The device lacks integrated reverse-polarity protection. External protection - such as a series Schottky diode or ideal diode controller - must be added if the application risks battery reversal, especially in service/maintenance scenarios. ST recommends using TVS diodes on VS for load-dump suppression per ISO 7637-2.