STMicroelectronics L99VR02J

Overview

L99VR02J from STMicroelectronics is an AEC-Q100 qualified automotive linear voltage regulator in PowerSSO-12 package, delivering up to 500 mA output current with ±2% output voltage accuracy and ≤1 µA quiescent current when disabled. It supports configurable fixed outputs (0.8 V to 5 V), withstands 40 V load dump transients, and operates across -40 °C to 175 °C junction temperature - deployed in engine control units for post-regulation of microcontroller core supplies.

For engineers reviewing the L99VR02J datasheet, L99VR02J pinout, L99VR02J application, or L99VR02J equivalent, key selection considerations include programmable short-circuit current via external resistor, autonomous watchdog timing set by VCW capacitor, thermal warning output behavior under overtemperature/overvoltage, and fast output discharge (75 Ω typical) during disable.

Technical Context

The L99VR02J uses a p-channel MOSFET pass element enabling low dropout voltage (500 mV at 500 mA, VO = 5 V) and stable operation with ceramic output capacitors ≥3.3 µF. Its internal architecture integrates a pretrimmed voltage reference, precision SELx-based output selection logic, and independent analog blocks for reset generation, watchdog timing, and thermal warning.

It features dual protection modes: autonomous watchdog triggered by Wi square-wave frequency monitoring (with VCW-set timeout), and advanced thermal warning (TW pin pulled low above 140–165 °C or issuing square wave during overvoltage). Output current limiting is externally programmable via Ishort pin resistance, with short-circuit thresholds ranging from 120 mA to 1085 mA depending on configuration.

Key Specifications

Pinout & Package

Package: PowerSSO-12 (exposed thermal pad, surface-mount, RoHS-compliant). Thermal pad must be soldered to PCB ground plane for effective heat dissipation (R_thj-PCB = 10 °C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with NCP1117ST50T3G and TLE42754G, L99VR02J uniquely combines eight output voltages, autonomous watchdog, thermal warning with overvoltage indication, and programmable short-circuit current - making it the only option among the three qualified for ASIL-B–relevant subsystems requiring layered diagnostics.

Availability

L99VR02J is available at Aetrix Electronics and suitable for engine control units, ADAS camera modules, transmission control systems, and electric power steering sensor interfaces requiring stable component supply across extended temperature and automotive qualification requirements.

Supply support for L99VR02J 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 consumer markets since 1987.

L99VR02J belongs to ST's L99 automotive power management portfolio, engineered specifically for functional safety-critical vehicle subsystems requiring diagnostic-rich, AEC-Q100 Grade 0 LDO regulation with extended temperature operation.

FAQ

What is the minimum input voltage required for L99VR02J to regulate at 3.3 V output?

The datasheet specifies a minimum input voltage of 5 V for VO = 3.3 V under full-load conditions (IO = 500 mA), due to its dropout voltage characteristic. At light load (IO = 1 mA), regulation is maintained down to VS = 3.95 V. Input ceramic capacitance ≥4.7 µF is mandatory to ensure stability at low VS.

How does the thermal warning (TW) pin behave during overvoltage versus overtemperature events?

During overtemperature (T_J > 140–165 °C), TW is actively pulled low. During output overvoltage (>6.5–13.5% above nominal), TW outputs a square wave with period 160–335 µs. These two modes are mutually exclusive and distinguishable in firmware - enabling separate diagnostic responses for thermal derating versus power stage fault.

Can the watchdog timer be disabled, and if so, how?

Yes - the watchdog is disabled when the Wi input is held continuously high or low (outside valid square-wave frequency window), or when the I_{W_off} threshold (0.4–1.5 mA) is exceeded. No dedicated disable pin exists; disabling occurs inherently via absence of valid refresh signal or excessive Wi current.

Is external compensation required for stability with the recommended 3.3 µF ceramic output capacitor?

No external compensation is required. The L99VR02J is internally compensated for stability with ceramic output capacitors ≥3.3 µF and ESR ≤10 mΩ. The datasheet confirms negligible ESR effect on stability, and application schematics specify only CO = 3.3 µF without series resistance or parallel RC networks.