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LIN v2.2A interface with OCS message decoding capability

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5.4 V min operating voltage at VIN battery input for start-up

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Full ISO 26262 compliant, ASIL-D systems ready

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Packaging 128 pin

Description

The L9691 is an advanced airbag system chip solution targeted for the global airbag market.

High frequency power supply design optimizes system cost by using smaller and less expensive external

components. All switching regulators operate at 2 MHz and all buck converters have integrated synchronous

rectifiers.

The reserve capacitor is electrically isolated from the boost regulator by integrated switches and external

resistors, controlling in-rush current. A capacitor discharge switch is integrated to discharge the capacitor at

shutdown.

Low quiescent current permits the device to be directly connected to battery. In this mode, device start-up and

shutdown are controlled through the wake-up input pin (actually, shutdown needs also dedicated SPI command

too). The power supply and crossover function are controlled automatically through the internal state machine.

For systems with high feature content, two L9691 devices can be used in a master/slave configuration.

The L9691 provides two fully isolated deployment voltage regulators, using the external safing FETs as power

elements in the regulator loop. Deployment voltage is set to a nominal 18V value to further optimize system cost.

Integrated safing logic uses a rolling average algorithm and decodes all sensor information within the system

remote sensor SPI bus. Number of samples and thresholds are user-programmable. An alternative safing function

permits arming from an external source through the Global SPI bus (E2E communication).

Dual SPI interfaces separate device global functions and remote sensors. LIN interface is available, providing

OCS message decoding for passenger loop inhibition.

L9691

DB4803 - Rev 2

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