1 General description

FS2400 is a family of automotive safety system basis chip (SBC) devices with multiple power supplies designed to support secure car access application using ultra-wide band (UWB), near-field communication (NFC), and Bluetooth Low Energy (BLE) devices. The FS2400 can also fit other small applications requiring low power and CAN FD communication.

This family of devices supports a wide range of applications, offering a choice of output voltage settings, physical interface, integrated system-level features to address low-power and noise-sensitive applications with automotive safety integrity levels (ASIL) up to ASIL B.

The FS2400 integrates a battery-connected switched-mode regulator (V1) and a battery-connected linear regulator (V3) to supply microcontroller, communication devices, and others. V1 offers a high-performance switching regulator capable of operating in Pulse Frequency Modulation (PFM) mode and Force Pulse Width Modulation (FPWM) mode. The mode of operation can be changed using wake pins to optimize noise management.

The FS2400 is developed in compliance with the ISO 26262:2018 standard. It includes enhanced safety features, with fail-safe output, becoming part of a full safety-oriented system, covering ASIL B safety integrity level. The FS2400 is offered in a 5 mm x 5 mm, 32-Ld HVQFN package with wettable flanks.

2 Features and benefits

Operating range

• 40 V DC maximum input voltage

• Low-power off mode with low sleep current and multiple wake-up sources

• Low-power on mode with HVBUCK (V1) active, HVLDO (V3) selectable by OTP and multiple wake-up

sources

Power supplies

• V1: High-voltage synchronous buck converter with integrated FETs. Configurable output voltage (1.9 V to 5 V)

and switching frequency, output DC current capability up to 400 mA and PFM mode for Low-power on mode

operation

• V3: High-voltage LDO regulator for microcontroller I/O support with selectable output voltage between 3.3 V or

5 V and up to 150 mA current capability

System support

• One CAN FD supporting up to 5 Mbps communication following ISO 11898-2:2016 and SAE J2284 standards

• Four wake-up inputs (40 V capable): WAKEx pins, HVIO1 pin, CAN FD or SPI command

• Hardware ID detection capability

• One high-voltage I/O with wake-up capability (40 V capable): HVIO1

• Device control via 32 bits SPI interface, with CRC

• Integrated long duration timer (LDT) for system shutdown and wake-up control, programmable up to 194 days

• 12-channel analog multiplexer (AMUX) for system monitoring (temperature, battery voltage, internal voltages)

Functional safety

• Developed following ISO 26262:2018 standard to fit for ASIL B applications

• Internal monitoring circuitry with its own reference

• Additional input for external voltage monitoring

• Window or timeout watchdog function to monitor the MCU software failure

• Analog built-in self-test (ABIST) on demand

• Safety outputs (RSTB, LIMP0)

• Safety input to monitor external IC state (ERRMON)

Configuration and enablement

• HVQFN32EP: QFN, 32 pins with exposed pad for optimized thermal management, wettable flanks, 5 mm x 5

mm x 0.85 mm, 0.5 mm pitch

• Permanent device customization via one time programmable (OTP) fuse memory

• OTP emulation mode for system development and evaluation