STMicroelectronics SPSA068-TR

Overview

SPSA068-TR from STMicroelectronics is an AEC-Q100 qualified automotive PMIC integrating a synchronous current-mode BUCK regulator (5.0 V / 3.3 V / 1.2 V at up to 1.0 A) and a precision voltage reference (±1% accuracy at 20 mA), both programmable via NVM. It features SPI interface with CRC, adjustable window watchdog, reset output, thermal warning/shutdown, and fault detection pin - designed for functional safety–compliant MCU power management in passenger car applications.

For engineers reviewing the SPSA068-TR datasheet, SPSA068-TR pinout, SPSA068-TR application, or SPSA068-TR equivalent, this device supports critical automotive subsystems requiring dual regulated rails, diagnostics, low-power operation (<5 μA standby), and ASIL-B–capable monitoring functions including voltage supervisors, ground-loss detection, and open-load diagnosis.

Technical Context

The SPSA068-TR implements a current-mode BUCK converter with integrated high-side (395 mΩ) and low-side (200 mΩ) MOSFETs, supporting selectable switching frequencies of 0.4 MHz or 2.4 MHz and spread-spectrum modulation (±3%) to reduce EMI. Its dual-rail architecture delivers independent regulation: one buck stage for MCU core/peripheral supply (up to 1 A), and a separate ±1% accurate reference rail (up to 20 mA) with tracking behavior during power-up.

Functional safety is enforced through hardware-based monitors - including VS undervoltage (3.8–4.2 V), BUCK/VREF UV/OV thresholds with configurable hysteresis, PGND/AGND loss detection, and SPI-accessible status flags. The device enters low-power mode (50 μA typical) on command and exits via WAKE_LPM with <1 μs digital filter delay, enabling rapid wake-up while maintaining diagnostic readiness.

Key Specifications

Pinout & Package

SPSA068-TR is housed in a QFN32L EPAD package (5.0 × 5.0 × 1.0 mm), thermally enhanced with exposed pad soldered to PCB ground plane for optimal thermal resistance (R_{th j-a} = 32 °C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MPQ4333-AEC1, SPSA068-TR adds integrated VREF, SPI diagnostics, and ASIL-B–ready supervision - eliminating external components and enabling functional safety compliance. Against TPS65381A-Q1, it delivers superior EMI performance via spread spectrum and earlier thermal intervention (warning at 140 °C vs. none), reducing system-level thermal design complexity.

Availability

SPSA068-TR is available at Aetrix Electronics and suitable for automotive body electronics, ADAS camera ECUs, instrument cluster controllers, and infotainment head units requiring stable component supply, AEC-Q100 qualification, and functional safety–ready power management.

Supply support for SPSA068-TR 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, industrial, and power management solutions with over 40 years of automotive IC experience.

The SPSA068-TR belongs to ST's automotive-grade PMIC portfolio designed specifically for functional safety–compliant MCU power systems in passenger vehicles - emphasizing integrated diagnostics, low-power operation, and robustness under harsh electrical conditions.

FAQ

What is the minimum input voltage required for the BUCK regulator to deliver 5.0 V output?

The BUCK regulator requires VS ≥ 4.5 V to maintain 5.0 V output under full 1.0 A load when configured for 5.0 V. Below 4.5 V, output drops linearly due to high-side FET R_on (395 mΩ); at VS = 4.2 V, output falls to ~4.6 V. This behavior is documented in Table 5 (General characteristics) of DS14755 Rev 1, where VS operating range for BUCK = 5 V is specified as 4.5–19 V in LPM mode and 4.2–19 V in active mode.

How does the VREF output track the BUCK output during power-up?

VREF tracks BUCK during power-up by mirroring its ramp rate until BUCK reaches its programmed UV threshold (e.g., 84–96% of target). This ensures analog circuitry powered by VREF remains biased correctly relative to the MCU supply, preventing latch-up or undefined states. Tracking behavior is enabled by default and cannot be disabled - it is hardwired in the internal control logic per Section 4.1 of DS14755 Rev 1.

Can the SPSA068-TR operate without SPI communication after initial NVM programming?

Yes - once NVM parameters (output voltages, frequency, watchdog settings) are programmed at first power-up, the device operates autonomously without SPI. SPI is optional for runtime diagnostics, fault logging, or dynamic reconfiguration; all safety-critical functions (UV/OV detection, thermal shutdown, FAULT/NRST assertion) remain fully active without SPI traffic.

What is the maximum allowable output capacitor ESR for the VREF rail?

The maximum allowable ESR for the VREF output capacitor is 100 mΩ, measured at 100 kHz–1 MHz, as specified in Table 5 (CVREF and RESR_CVREF entries) of DS14755 Rev 1. Exceeding this value may cause instability or false VREF_UV flag assertion during startup, especially when combined with large capacitance (>1.4 μF with BUCK soft-start disabled).