onsemi NCV8668ABD133R2G

Overview

NCV8668ABD133R2G from onsemi is a 3.3 V, 150 mA automotive-grade LDO regulator with integrated window watchdog, reset output, and enable control-designed for microprocessor power supervision in body control modules and instrument clusters. It delivers ±1.5% output accuracy over −40°C to +125°C, features 38 µA typical quiescent current, and operates across 4.5 V to 40 V input range.

For engineers reviewing the NCV8668ABD133R2G datasheet, pinout, applications, or equivalent options, key selection criteria include its 3.3 V fixed output, SOIC-8 package with exposed ground pad, 16 ms fast reset delay, 93% VOUT reset threshold, and watchdog timing compatibility with automotive ASIL-B–level monitoring requirements.

Technical Context

The NCV8668ABD133R2G implements a precision bandgap reference-based regulation loop with thermal shutdown (175°C trip), current limiting (205–525 mA), and reverse output current protection. Its window watchdog uses dual mode bits (WM1/WM2) to configure fast/slow timing states, with sampling intervals of 0.5–1.2 ms and open/closed window durations of 32–76.8 ms.

Reset generation is triggered by either VOUT dropping below 93% of nominal (3.069 V) or VIN falling below 3.8 V-ensuring fail-safe behavior during brown-out. The open-drain RO pin includes an internal 30 kΩ pull-up to VOUT, eliminating external components for 3.3 V operation only when used with compatible microprocessor inputs.

Key Specifications

Pinout & Package

NCV8668ABD133R2G is packaged in Pb-free SOIC-8 (Case 751-07) with exposed pad (EPAD) thermally and electrically connected to GND. The 8-pin layout supports compact PCB placement and enhanced thermal dissipation (R_JL4 = 28.5°C/W, R_JPad = 14.8°C/W).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar LDO-with-watchdog applications.

Compared with NCV8668ABD133R2G, the NCV8668ABPD33R2G offers superior thermal performance in identical functionality, while TLV70733PDQNR trades integrated supervision for lower quiescent current and reduced cost-making it viable only in non-automotive contexts where external watchdogs are acceptable.

Availability

NCV8668ABD133R2G is available at Aetrix Electronics and suitable for body control modules, instrument clusters, and occupant protection systems requiring stable component supply with automotive-grade reliability and long-term lifecycle support.

Supply support for NCV8668ABD133R2G 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

onsemi (formerly ON Semiconductor) is a global semiconductor leader specializing in energy-efficient, high-reliability silicon solutions for automotive, industrial, and cloud power applications.

The NCV8668 series is part of onsemi's automotive power management portfolio, engineered specifically for ASIL-B–compliant microprocessor supervision in harsh environments-including extended temperature operation, load dump tolerance, and integrated functional safety features.

FAQ

What is the reset threshold voltage for NCV8668ABD133R2G?

The NCV8668ABD133R2G features a VOUT-dependent reset threshold of 93% of nominal output voltage, equating to 3.069 V at 3.3 V output. This threshold includes 2% hysteresis to prevent chatter during marginal conditions. The device also monitors VIN and asserts reset if input falls below 3.8 V - a feature specific to 3.3 V variants to cover cold-crank scenarios.

Does NCV8668ABD133R2G require an external pull-up resistor on the RO pin?

No - the NCV8668ABD133R2G integrates a 30 kΩ pull-up resistor from RO to VOUT, making external pull-up unnecessary for standard 3.3 V logic interfacing. However, if the connected microcontroller operates at a different voltage (e.g., 5 V tolerant inputs), an external pull-up to that rail may be needed to ensure valid logic-high levels on RO.

How is watchdog timing configured on NCV8668ABD133R2G?

Watchdog timing on the NCV8668ABD133R2G is set via WM1 and WM2 pins: both pulled low selects Fast mode (tOW = tCW = tIW = 32 ms); WM1 high + WM2 low selects Slow mode (64 ms values). The device uses internal sampling (tsam = 0.5–1.2 ms) to validate WDI pulses - requiring two consecutive HIGH followed by two LOW samples within the sampling window to register a valid trigger.

What package type does NCV8668ABD133R2G use, and how is thermal performance affected?

NCV8668ABD133R2G uses a Pb-free SOIC-8 NB package (Case 751-07) with an exposed pad (EPAD) connected to GND. With proper PCB layout (≥645 mm² 1 oz copper), its junction-to-pad thermal resistance is 14.8°C/W, enabling up to 1.3 W power dissipation at 25°C ambient - significantly better than standard SOIC-8 variants without EPAD.

Can NCV8668ABD133R2G operate during automotive load dump events?

Yes - the NCV8668ABD133R2G supports transient input voltages up to 45 V for durations less than 100 ms, satisfying ISO 7637-2 Pulse 5a load dump requirements. Its internal protection circuitry (including thermal shutdown and current limiting) remains fully functional during such events, ensuring uninterrupted supervision of downstream microprocessors.