STMicroelectronics L9680

Overview

L9680 from STMicroelectronics is an AEC-Q100 qualified automotive safety IC for mid/high-end airbag systems and cut-off battery applications. It integrates 12-channel squib/pyroswitch drivers (25 V max), four PSI-5 remote sensor interfaces, nine DC sensor inputs, three configurable GPOs, dual watchdog timers, and five on-chip regulators-including ERBOOST (23/33 V), SYNCBOOST (12/14.75 V), SATBUCK (7.2/9 V), VCC buck (3.3/5.0 V), and VSF safing regulator-enabling full airbag control and pyro-fuse management in a single TQFP100 package.

For engineers reviewing the L9680 datasheet, L9680 pinout, L9680 application, or L9680 equivalent, this device supports critical functional safety requirements including R_measure/STB/STG/leakage diagnostics, temporal and algorithmic watchdogs, user-customizable safing logic, end-of-life disposal interface, and SPI-controlled deployment sequencing with current monitoring and fault reporting.

Technical Context

The L9680 implements a multi-regulator power architecture: ERBOOST delivers up to 70 mA at 23 V or 33 V for energy reserve charging; SYNCBOOST supplies 12 V or 14.75 V to PSI-5 sensors; SATBUCK powers remote wheel speed sensors at 7.2 V or 9 V; VCC buck provides MCU core voltage at 3.3 V or 5.0 V; and VSF regulates the high-side safing switch. All switching regulators operate at 1.882 MHz for compact external component sizing.

Its safety-critical subsystems include 12 independent HSD/LSD deployment drivers with per-channel current monitoring, R_measure, STB, STG, and leakage diagnostics; integrated ADC-based system voltage monitoring; and dual watchdogs-WD1 (temporal) and WD2 (algorithmic)-with configurable retry, seed/key authentication, and recoverable reset assertion.

Key Specifications

Pinout & Package

Package: TQFP100 exposed pad down (14 mm × 14 mm × 1.0 mm), RoHS-compliant, with thermal pad for enhanced heat dissipation in high-power deployment scenarios.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar automotive airbag controller applications.

Compared with MC33972 and RAA278812, the L9680 uniquely integrates energy reserve charging, PSI-5 master functionality, and FMVSS 208-compliant passenger inhibit logic-making it the only solution that satisfies full ASIL-B airbag control, pyro-fuse management, and regulatory occupant sensing in a single IC.

Availability

L9680 is available at Aetrix Electronics and suitable for mid/high-end airbag systems, cut-off battery systems, and pyro fuse/switch management applications requiring stable component supply, long-term automotive lifecycle support, and AEC-Q100 qualification.

Supply support for L9680 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 over 30 years of automotive IC design expertise and ISO/TS 16949-certified manufacturing.

The L9680 belongs to ST's SAFETYline portfolio-designed specifically for ASIL-B compliant restraint control units, integrating functional safety mechanisms, diagnostic coverage, and automotive-grade reliability into single-chip airbag system controllers.

FAQ

What is the maximum continuous current rating of the integrated energy reserve crossover switch?

The L9680's integrated energy reserve crossover switch supports up to 912 mA continuous current with a typical R_DS(on) of 3 Ω. This rating is validated across the full −40 °C to +95 °C operating temperature range and includes built-in thermal derating logic to prevent latch-up during sustained high-current deployment sequences.

How does the L9680 perform squib resistance measurement without external components?

The L9680 executes R_measure diagnostics using its internal current sources and ADC path: it applies a known current step through the squib loop, measures resulting voltage drop across internal sense resistors, and computes resistance via calibrated gain/offset coefficients stored in OTP memory-requiring no external test circuitry.

Can the PSI-5 interface operate independently of the main SPI host controller?

Yes-the PSI-5 interface operates autonomously using its dedicated SYNCBOOST clock and internal state machine. It buffers sensor data in local registers and signals readiness via interrupt; the host SPI only reads completed frames, enabling deterministic timing even during heavy SPI bus load or MCU sleep states.

What safety certifications does the L9680 hold beyond AEC-Q100?

In addition to AEC-Q100 Grade 2 qualification, the L9680 is designed to support ISO 26262 ASIL-B development workflows. Its architecture includes dual watchdogs, lockstep-capable register access, fault collection registers (FLTSR), and diagnostic coverage documented in ST's Safety Manual DS11615 Annex B-enabling systematic safety analysis by Tier 1 integrators.