Driver with 8 Channels Equipped with Failsafe Limp-Home Function for Safe Operation in Case of Failure
ST's L9800: A Versatile 8-Channel Low-Side Driver for Automotive Applications
STMicroelectronics' L9800 is an 8-channel low-side driver designed specifically for automotive applications. This innovative device, developed by STMicroelectronics, offers a range of features that make it an ideal choice for controlling LEDs and relays in various automotive components.
One of the key advantages of the L9800 is its compatibility with different load types, including resistive, inductive, and capacitive loads. This versatility allows it to be used with a wide variety of automotive components, increasing its utility in various applications.
The L9800 also boasts advanced diagnostics and protections, such as open load detection, overcurrent protection, overtemperature detection, and short to ground detection. These features enhance the reliability and safety of vehicle systems by providing real-time diagnostics and protection per channel.
In terms of control interfaces, each of the eight output channels can be driven either through an SPI (Serial Peripheral Interface) or via dedicated parallel input pins, offering flexible control options. Two dedicated input pins (IN0 and IN1) allow for direct control and pulse-width modulation (PWM), with programmable assignment to output channels via SPI.
The L9800 also incorporates special-purpose pins, such as NRES, which resets internal registers to their default values, and DIS, which disables all channels. These features contribute to the device's ease of use and flexibility in various applications.
Another notable feature is the L9800's limp-home and daisy chain functionality. It supports limp-home mode, ensuring continued operation under fault conditions, and daisy chaining allows multiple devices to be connected with no limitation on SPI bit numbers in the chain, facilitating scalable system designs.
The L9800 is designed to operate under a wide range of conditions, including a battery cranking voltage as low as 3 V, making it suitable for start-stop systems. It also maintains very low quiescent current under reset conditions, contributing to reduced power consumption when inactive.
Moreover, the L9800 aids in vehicle reliability and eases system-level ISO 26262 certification up to ASIL B, demonstrating its commitment to safety and reliability in automotive applications.
The L9800 comes in a compact TFQFN24 package (4x4x0.9 mm), suitable for space-constrained automotive circuit boards. To help developers evaluate the benefits of the device, STMicroelectronics provides an evaluation board (STEVAL-L9800), which includes a full-featured 1-MB SPC58 MCU discovery board (AEK-MCUC1MLIT1).
In summary, the L9800 is a robust, flexible, and automotive-grade 8-channel low-side driver optimized for reliable control of LEDs and relays. It combines versatile load compatibility, comprehensive diagnostic/protection features, flexible input modes (SPI or parallel), and automotive-specific functions like limp-home mode and voltage cranking tolerance, making it an ideal choice for various automotive applications.
[1] Reference: STMicroelectronics L9800 8-Channel Low-Side Driver for Automotive Applications Datasheet, Revision 1.2, 2021.
Data-and-cloud-computing can be used to remotely monitor and manage the L9800's performance in various automotive applications, enhancing system efficiency and diagnostics.
Incorporating this 8-channel low-side driver, ST's L9800, into a technology-driven vehicle creates a smart and automated system that leverages both physical components (like the driver itself) and digital technologies (such as data-and-cloud-computing).
