NXP Semiconductors MC33FS8435G0ES

Overview

MC33FS8435G0ES from NXP Semiconductors is an ASIL B–capable automotive fail-safe system basis chip integrating three synchronous buck converters (BUCK1/2/3), one boost converter, two LDOs, and comprehensive safety monitoring. It delivers up to 3.6 A per buck rail, supports 60 V DC input, and features SPI/I²C control, frequency synchronization, and fail-safe output for radar and ADAS domain controllers.

For engineers reviewing the MC33FS8435G0ES datasheet, MC33FS8435G0ES pinout, MC33FS8435G0ES application, or MC33FS8435G0ES equivalent, this device is selected for multi-rail power sequencing in safety-critical 12 V/24 V automotive systems requiring configurable voltage rails, thermal shutdown response, and integrated functional safety monitoring per ISO 26262.

Technical Context

The MC33FS8435G0ES implements a hierarchical power management architecture with independent control loops for VPRE (external synchronous buck controller), BUCK1 (MCU core supply with SVS), BUCK2 and BUCK3 (configurable low-voltage rails), BOOST (integrated low-side switch), and dual LDOs (for MCU I/O and ADC). All regulators support programmable soft-start and power-up sequencing across eight slots.

Safety logic includes dedicated monitoring of VCOREMON, VDDIOMON, VMON1–VMON4, FCCU inputs, and ABIST/LBIST self-test. Fail-safe state machine asserts FS0B on fault detection, with infinite auto-retry enabled and configurable deep fail-safe behavior per OTP configuration.

Key Specifications

Pinout & Package

MC33FS8435G0ES is housed in HVQFN56 (SOT684-23), an 8 mm × 8 mm × 0.85 mm thermally enhanced wettable flank package with exposed pad (EP) for GND connection. Pin count: 56 terminals, 0.5 mm pitch.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar automotive power management applications.

Compared with MC33FS8430G0ES, MC33FS8435G0ES adds FCCU monitoring and extended VMON capability for tighter safety partitioning; compared with MC33FS8530A0ES, it provides ASIL B compliance at lower complexity and cost while retaining identical pinout, sequencing flexibility, and triple-buck architecture.

Availability

MC33FS8435G0ES is available at Aetrix Electronics and suitable for radar sensor modules, ADAS domain controllers, vision camera systems, and infotainment head units requiring stable component supply, long-term automotive qualification, and functional safety traceability.

Supply support for MC33FS8435G0ES 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

NXP Semiconductors is a global semiconductor company headquartered in Eindhoven, Netherlands, specializing in secure connectivity solutions for automotive, industrial, and IoT markets.

The FS84 product line delivers ASIL B–compliant system basis chips optimized for radar, vision, and domain controller applications-integrating power conversion, safety monitoring, and communication interfaces into a single automotive-grade IC.

FAQ

What is the maximum output current capability of each buck regulator in the MC33FS8435G0ES?

The MC33FS8435G0ES supports up to 4.5 A peak current on BUCK1, BUCK2, and BUCK3. BUCK1 is configured for 1.8 V @ 4.5 A in this variant, BUCK2 for 1.8 V @ 4.5 A, and BUCK3 for 3.3 V @ 4.5 A. Current capability is set by OTP programming and verified per AEC-Q100 testing at 125 °C junction temperature. The MC33FS8435G0ES datasheet specifies these values in Table 1 and Section 4.1 Main OTP flavors.

Does the MC33FS8435G0ES support multiphase operation between its buck regulators?

Yes, the MC33FS8435G0ES supports multiphase operation between BUCK1 and BUCK2 to extend total current capability to 7.2 A peak on a single rail. Phase shifting is configurable via OTP (e.g., BUCK1 delay 0, BUCK2 delay 2), enabling interleaved switching that reduces input/output ripple and improves thermal distribution. This feature is documented in the "Based on device options" section under BUCK2 description and confirmed in the MC33FS8435G0ES OTP configuration table.

How does the fail-safe output (FS0B) behave during thermal shutdown in the MC33FS8435G0ES?

During thermal shutdown (TSD), the MC33FS8435G0ES asserts FS0B low and initiates deep fail-safe mode with infinite auto-retry. BUCK1, BUCK2, and BUCK3 shut down with DFS (deep fail-safe) behavior, and the fail-safe state machine holds FS0B active until temperature falls below the hysteresis threshold and internal reset conditions are met. This behavior is explicitly defined in the MC33FS8435G0ES OTP flavor table and Section 4.2 Fail-safe OTP flavors.

Can the MC33FS8435G0ES be used with both SPI and I²C interfaces simultaneously?

No, the MC33FS8435G0ES supports either SPI or I²C-not both concurrently. Interface selection is fixed at power-on based on strap pin configuration (not user-configurable in runtime). The default I²C address is 0x20, and SPI uses standard four-wire protocol (MISO/MOSI/SCLK/CSB). This single-interface constraint is specified in Section 7.2 Pin Description and confirmed in the communication block diagram (Figure 2).

What is the purpose of the PSYNC pin on the MC33FS8435G0ES, and how is it used in system design?

The PSYNC pin on the MC33FS8435G0ES serves as a bidirectional power synchronization signal to align switching frequencies across multiple PMICs-reducing beat frequencies and improving system-level EMC. In master mode, it outputs FSYNC; in slave mode, it accepts external synchronization. For MC33FS8435G0ES, PSYNC is disabled by default but can be enabled via OTP to synchronize with a second FS85 device or external PMIC. This capability is detailed in the "Other" row of the OTP flavor table and Section 4.1.