STMicroelectronics L9662TR

Overview

L9662TR from STMicroelectronics is an octal squib driver and quad Manchester/PSI5 satellite sensor interface ASIC for automotive airbag control units. It integrates 8 high-current deployment drivers (1.75 A min / 1.0 ms), dual SPI interfaces (5.5 MHz), and diagnostics for squib short-to-ground/battery, MOS health, and resistance measurement - deployed in production airbag systems requiring ASIL-B compliance.

For engineers reviewing the L9662TR datasheet, L9662TR pinout, L9662TR application, or L9662TR equivalent, key selection criteria include simultaneous 8-channel firing capability, VRES operating range (7–37 V), Hall sensor support on channels 3–4, PSI5 v1.2 protocol decoding, and independent current trip point programming per satellite channel.

Technical Context

The L9662TR implements two independent functional domains: (1) eight high-side/low-side squib drivers with programmable firing current (1.2–1.75 A) and duration (0.65–2 ms), each with dedicated VRESx supply and ground pins; (2) four satellite sensor interfaces supporting Manchester-1/2 and PSI5 (Parity) protocols with variable bit-rate detection, sync pulse generation, and minibus topology support.

Diagnostic architecture includes SPI-accessible registers for real-time fault reporting (squib open/short, MOS short-to-ground, voltage measurement errors), analog output (AOUT) for loop resistance diagnostics, and dual SPI interfaces - one for deployment control (SPI_D), one for satellite communication (SPI_S) - with separate chip select, clock, and data lines to prevent interference during safety-critical deployment sequences.

Key Specifications

Pinout & Package

Package: LQFP64 (10 × 10 × 1.4 mm), thermally enhanced with 9 dedicated GND pins (GND, GND0–GND7, AGND) and isolated power grounds per squib loop to minimize crosstalk and ensure diagnostic integrity.

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 RAA278812, the L9662TR uniquely balances ASIL-B compliance, dual-protocol satellite support (Manchester + PSI5), Hall sensor integration, and on-chip analog resistance diagnostics - making it optimal for mid-tier automotive ACUs targeting cost-sensitive yet future-proof platform scalability.

Availability

L9662TR is available at Aetrix Electronics and suitable for automotive airbag control units, crash sensor interface modules, and occupant classification systems requiring stable component supply across extended vehicle production lifecycles.

Supply support for L9662TR 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 ICs, power management, and microcontrollers - with over 25 years of safety-critical automotive ASIC development experience.

The L9662TR belongs to ST's Safety Power & Interface product line, designed specifically for ASIL-B compliant airbag and restraint system controllers - emphasizing diagnostic completeness, voltage transient resilience, and multi-protocol sensor interoperability.

FAQ

What is the maximum number of squib channels that can be fired simultaneously?

The L9662TR supports simultaneous firing of all 8 squib channels. This capability is hardware-gated and verified under worst-case VRES conditions (7–37 V) and ambient temperature (−40 °C to +85 °C). Each channel delivers ≥1.75 A for 1.0 ms or ≥1.2 A for 2.0 ms, with independent VRESx supplies ensuring consistent energy delivery without cross-loop interference.

Does the L9662TR support both Manchester and PSI5 protocols on the same satellite channel?

No - each satellite channel (IF0–IF3) is configured at startup for either Manchester-1/2 or PSI5 (Parity) mode via SPI register MCR D13:D10; mixed-mode operation per channel is not supported. However, different channels can operate in different protocols (e.g., IF0 = Manchester, IF1 = PSI5), enabling heterogeneous sensor integration within one ASIC.

How is squib loop resistance measured using the L9662TR?

Resistance measurement uses the analog output AOUT, which provides a ratiometric voltage proportional to the voltage drop across the external reference resistor (IREF) in series with the squib. The value is read via external ADC and converted using calibration coefficients stored in SPI registers. This method enables non-intrusive, pre-deployment loop integrity checks without activating MOSFETs.

What diagnostic faults are reported through SPI registers?

SPI registers report squib-specific faults including short-to-ground, short-to-battery, open-load, and MOSFET degradation (via high-side/low-side diagnostic flags), plus satellite interface faults such as sync loss, Manchester/PSI5 frame errors, parity/CRC failures, and current limit violations. All faults are latched and readable via dedicated diagnostic status registers (e.g., DEPLOY_STATUSx, SAT_DIAG_STATUS).