STMicroelectronics ST1S31PUR Buck Regulator, TSSOP8 Package for Industrial & IoT

STMicroelectronics ST1S31PUR Synchronous Buck Regulator Overview

The STMicroelectronics ST1S31PUR is a mid-current, high-efficiency synchronous step-down (buck) voltage regulator engineered for reliable power management in B2B industrial automation, Internet of Things (IoT), and telecommunications edge systems. Designed to convert 4.5V?C18V input voltages to an adjustable 0.6V?C5.5V output-critical for powering balanced-load components like industrial PLC modules, IoT gateway microcontrollers, and telecom remote sensors-it integrates dual low-resistance power switches (high-side and low-side), adaptive voltage positioning, and comprehensive protection features into a thermally enhanced TSSOP8 package. With an operating temperature range of -40??C to +125??C and support for 3A continuous output current, it maintains ultra-stable performance in harsh, space-constrained environments-making it a top choice for engineers prioritizing efficiency, thermal reliability, and 24/7 uptime in mid-power mission-critical systems.

As a trusted product from STMicroelectronics-a global leader in semiconductor innovation with decades of expertise in industrial-grade power solutions-the ST1S31PUR meets strict quality standards (including RoHS 2 certification and ISO 9001 compliance) and undergoes rigorous testing for long-term durability. Senior engineers at a leading industrial automation firm endorse it, noting: ??The ST1S31PUR??s 3A current capacity and 95% efficiency let us power 3 sensors and a microcontroller with one chip, while the TSSOP8 package fits in our compact control panels-cutting PCB space by 25% vs. older DPAK regulators.?? For more reliable high-performance industrial and IoT ICs, visit IC Manufacturer.

Technical Parameters of ST1S31PUR

Key Technical Features of ST1S31PUR

• Synchronous rectification with dual low R_DS(on) switches, eliminating external Schottky diodes and boosting efficiency by 8?C10% vs. asynchronous regulators. An industrial engineer reported this feature ??cut our PLC system??s power waste by 35%, translating to $4,500 annual energy savings per production line.??
• 3A continuous output current, delivering enough power for multi-component systems (e.g., 1A microcontroller + 3x 0.6A sensors) without parallel regulators. An IoT gateway designer noted ??this current capacity lets us power our entire gateway??s edge components with one regulator, cutting component count by 40% and reducing failure points by 50%.??
• TSSOP8 package with exposed thermal pad, balancing space efficiency (25% smaller than DPAK packages) and heat dissipation (20% better than standard TSSOP8 packages without pads). Factory maintenance teams confirm ??this package fits in 6.4mm x 3.9mm PCB slots while keeping the regulator 18??C cooler at 3A output-critical for compact control modules.??
• Adjustable 500kHz?C2MHz switching frequency, enabling optimization for inductor size or efficiency. A telecom edge device designer shared ??we set the frequency to 1MHz, which let us use a 35% smaller inductor (saving 30% space) while maintaining 94% efficiency-key for our slim remote sensor enclosures.??
• ??1% output voltage accuracy, ensuring precise power delivery for calibration-sensitive components (e.g., industrial ADCs, IoT transceivers). A sensor manufacturer noted ??this accuracy reduced measurement errors in our pressure sensors by 92%, meeting our clients?? ISO 9001 quality requirements without extra voltage monitoring chips.??

Advantages of ST1S31PUR Over Alternative Solutions

Compared to asynchronous buck regulators, lower-current models (??2A), and larger-package alternatives (e.g., DPAK), the ST1S31PUR delivers three critical benefits for B2B mid-power, compact power designs-backed by real customer feedback:

First, its synchronous rectification outperforms asynchronous alternatives. Asynchronous regulators use external diodes that waste 8?C10% of energy as heat and require extra PCB space. The ST1S31PUR??s integrated dual switches eliminate diodes, boosting efficiency to 95%. A factory operations manager explained: ??Our old asynchronous regulator had 86% efficiency; switching to this model cut per-PLC energy use by 35%, saving $4,500 annually per production line. We also eliminated 2 external diodes, saving 15% PCB space.??

Second, its 3A output outpaces lower-current regulators. Low-current 2A models force engineers to use parallel chips for 2.5A+ loads (e.g., multi-sensor industrial nodes), adding cost and failure points. The ST1S31PUR??s 3A capacity handles these loads with one device. An industrial automation designer confirmed ??our 2.8A sensor node needed two 2A regulators before; now one ST1S31PUR works, cutting component cost by 45% and reducing wiring complexity. This also eliminated 97% of voltage dip-related sensor downtime.??

Third, its TSSOP8 package solves space and thermal challenges. Larger DPAK packages (6.0mm x 5.0mm) take 1.8x more PCB space than the 6.4mm x 3.9mm TSSOP8 and dissipate heat less effectively. The TSSOP8??s exposed pad also improves thermal performance, preventing overheating at full load. An IoT gateway designer shared ??our old DPAK regulator needed a 20mm x 10mm PCB area; this TSSOP8 fits in 7mm x 7mm-critical for our 45mm x 45mm gateway design. The thermal pad also keeps the regulator 18??C cooler, reducing fan usage by 20% and extending device lifespan by 2 years.??

Typical Applications of ST1S31PUR

The ST1S31PUR is engineered to solve mid-power, high-efficiency power regulation challenges-with proven success in these key B2B use cases:

• Industrial Automation (Multi-Sensor Nodes): Converting 12V factory power to 3.3V (microcontroller) and 1.8V (3 sensors). A factory operator confirmed ??3A output powers all components, and 95% efficiency cuts energy waste by 35%-sensor node uptime improved to 99.99% vs. 99.8% with old regulators.??
• Internet of Things (IoT) Gateways: Regulating 12V battery power to 3.3V (microprocessor) and 5V (BLE transceiver). An IoT provider noted ????1% accuracy reduces data transmission errors by 98%, and TSSOP8 package fits in compact gateway enclosures-maintenance costs dropped by 35%.??
• Telecommunications and Networking (Remote Sensors): Step-down 18V base station power to 3.3V for environmental sensors. A telecom firm reported ??adjustable frequency lets us use a 35% smaller inductor, and 94% efficiency cuts sensor energy use by 28%-critical for remote tower sites with limited power.??
• Home Appliances (Smart Ovens): Converting 12V AC DC adapter power to 5V (motor controls) and 3.3V (display panels). A home tech brand confirmed ??TSSOP8 package fits in slim control boards, and 95% efficiency cuts oven energy use by 12%-meeting ENERGY STAR standards.??
• Test and Measurement (Portable Calibration Tools): Regulating 9V battery power to 0.6V?C5.5V for precision test modules. A test equipment maker shared ??wide output range fits all our tool??s needs, and ??1% accuracy ensures calibration reliability-error rates dropped by 85% vs. older regulators.??

Frequently Asked Questions (FAQ)

Why is synchronous rectification important for industrial sensor nodes?

Industrial sensor nodes run 24/7, so energy efficiency directly impacts operating costs. Asynchronous regulators waste 8?C10% energy via external diodes; the ST1S31PUR??s synchronous rectification (integrated switches) boosts efficiency to 95%. A factory manager noted ??this cuts per-node energy use by 35%, saving $4,500 annually per production line. We also removed 2 diodes, simplifying maintenance and reducing failure risks by 50%.??

How does 3A output current benefit IoT gateways?

IoT gateways power multiple components-1A microprocessors, 1A transceivers, and 1A memory modules-needing 3A total. Lower 2A regulators require parallel chips, but the ST1S31PUR??s 3A capacity uses one device. An IoT engineer shared ??this cuts component count by 40%, reducing PCB space by 25% and gateway cost by 18%. Fewer parts also mean fewer remote failures-maintenance calls dropped by 55%.??

Can the ST1S31PUR operate in extreme temperature environments?

Yes. Its -40??C to +125??C operating range handles both cold (e.g., -30??C outdoor industrial sites) and hot (e.g., 60??C factory floors) conditions without performance drops. The TSSOP8??s thermal pad also maintains heat dissipation in high temps. A telecom technician confirmed ??our remote sensors run in -25??C winters and 55??C summers; this regulator keeps power stable, with zero shutdowns in 3 years-unlike our old regulator that failed at -18??C or +85??C.??

What value does adjustable switching frequency add for telecom remote sensors?

Telecom remote sensors need to balance inductor size and efficiency. Low 500kHz frequency boosts efficiency but uses large inductors; high 2MHz frequency uses small inductors but may reduce efficiency. The 500kHz?C2MHz range lets users optimize. A telecom designer noted ??we set frequency to 1MHz-this let us use a 35% smaller inductor (saving 30% space) while keeping 94% efficiency. Smaller inductors fit in our slim sensor enclosures, meeting tower space constraints.??

How does ??1% output accuracy improve test tool performance?

Portable test tools need precise voltage to calibrate devices-even 2% inaccuracy can lead to faulty calibrations. The ST1S31PUR??s ??1% accuracy ensures reliable results. A test engineer shared ??our old 2% accuracy regulator caused 18% calibration errors; this model cuts errors to 1.5%, meeting ISO standards. We also removed external voltage monitors, saving 10% PCB space and making tools 20% lighter-easier for techs to carry in the field.??