STMicroelectronics L9658

Overview

L9658 from STMicroelectronics is an octal squib driver and quad satellite sensor interface ASIC designed for automotive airbag control units (ACUs). It delivers ≥1.2 A for ≥2 ms and ≥1.75 A for ≥1 ms under 35 V load-dump conditions, supports Manchester protocol decoding for up to four satellite sensors (two configurable for Hall effect), and integrates independent high-side/low-side MOSFET diagnostics via SPI. Used in front/rear crash sensing modules requiring certified deployment reliability.

For engineers reviewing the L9658 datasheet, L9658 pinout, L9658 application, or L9658 equivalent, key selection criteria include squib current compliance under transient overvoltage, satellite channel bit-rate flexibility, resistance measurement capability, and diagnostic coverage for open/short-to-battery/short-to-ground faults on all eight deployment outputs and four sensor channels.

Technical Context

The L9658 implements dual-domain SPI control: one dedicated to arming sequence daisy-chaining (CS_A/SCLK_A/MOSI_A/MISO_A), another for deployment driver configuration and status reporting (CS_D/SCLK/MOSI/MISO), and a third for satellite sensor data acquisition (CS_S). Each of the eight squib drivers features independently programmable current trip points, fault timers, and MOSFET-level diagnostics including continuity, short-to-battery, short-to-ground, and resistance measurement.

Satellite interface supports two protocols ("A" fixed-length and "B" variable-length) with automatic bit-rate detection, FIFO buffering, and raw analog output (AOUT) for channel 3/4 Hall effect sensors. All diagnostics are reported through SPI register reads with defined fault code mapping per channel and driver.

Key Specifications

Pinout & Package

Package: 64-lead LQFP (10 × 10 mm, 0.5 mm pitch), RoHS-compliant, thermally enhanced for sustained squib drive duty cycles.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar squib driver and satellite sensor interface applications.

Compared with MC33816 and RAA215200, the L9658 uniquely combines octal squib drive with per-loop resistance measurement, triple isolated SPI domains, and dual-mode Hall interface-enabling single-chip implementation of ASIL-B compliant airbag controllers without supplemental analog or protocol translation ICs.

Availability

L9658 is available at Aetrix Electronics and suitable for automotive airbag control units, crash sensor modules, and occupant classification systems requiring stable component supply across extended production lifecycles and rigorous AEC-Q100 qualification.

Supply support for L9658 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, specializing in automotive-grade analog, power, and microcontroller solutions with deep expertise in functional safety and ASIL-certified design.

The L9658 belongs to ST's automotive safety ASIC product line, engineered specifically for airbag electronic control units requiring integrated squib driving, satellite sensor interfacing, and comprehensive diagnostics under ISO 26262 ASIL-B constraints.

FAQ

What is the maximum allowable VRES voltage for continuous operation?

The L9658 supports VRES input up to 35 V continuously, validated under ISO 7637-2 Pulse 5a (load dump) conditions. Operation above 35 V risks permanent damage to internal high-side MOSFETs and is outside absolute maximum ratings per Doc ID 14219 Rev 3 Section 3.2.

Does L9658 support daisy-chained satellite sensors?

Yes - the arming interface (CS_A/SCLK_A/MOSI_A/MISO_A) supports daisy-chained configuration of up to 16 satellite nodes using synchronous serial protocol, as shown in Figure 8 and detailed in Section 4.13 of the datasheet.

How is squib resistance measured without interrupting deployment readiness?

Resistance measurement occurs during diagnostic mode using controlled low-current pulses (<10 mA) applied between SQH and SQL pins while VRES is active. The resulting voltage drop is digitized internally and reported via SPI register 0x1E (RMSQx), preserving deployment state throughout.

Can L9658 drive squibs directly from a 12 V battery without external boost?

Yes - the L9658's integrated high-side drivers operate from VRES input, enabling direct connection to 12 V battery (or boosted rail up to 35 V). No external boost converter is required to achieve ≥1.2 A squib current, as confirmed in Section 4.9.1 and Table 7 of the datasheet.