STMicroelectronics ST1S10BPHR

Overview

ST1S10BPHR from STMicroelectronics is a monolithic synchronous step-down DC-DC regulator IC delivering up to 3 A output current, operating from 2.5 V to 18 V input, with adjustable output voltage down to 0.8 V and fixed 900 kHz switching frequency (or synchronizable from 400 kHz to 1.2 MHz). It integrates PMOS/NMOS power switches, features dynamic short-circuit protection, and is used in point-of-load regulation for FPGA core supplies and LCD monitor power rails.

For engineers reviewing the ST1S10BPHR datasheet, ST1S10BPHR pinout, ST1S10BPHR application, or ST1S10BPHR equivalent, this page delivers verified technical context, validated pin functions, confirmed thermal and efficiency specs, and real-world design constraints for high-density DC-DC conversion in consumer and industrial systems.

Technical Context

The ST1S10BPHR employs current-mode PWM control with internal soft-start (275 µs typical), enabling stable startup into heavy capacitive loads without external compensation. Its dual-VIN architecture separates analog supply (VIN_A) from high-current power input (VIN_SW), reducing noise coupling and improving transient response.

It integrates synchronous rectification using matched PMOS (0.12 Ω R_DS(on)) and NMOS (0.10 Ω R_DS(on)) switches, eliminating external Schottky diodes. Protection includes cycle-by-cycle overcurrent limiting (5 A), thermal shutdown at 150 °C with 15 °C hysteresis, and dynamic short-circuit recovery.

Key Specifications

Pinout & Package

ST1S10BPHR is packaged in PowerSO-8 (exposed pad), a thermally enhanced surface-mount package with 8 leads and integrated heat dissipation via the exposed copper pad soldered to PCB ground plane. Thermal resistance is R_thJA = 40 °C/W (JEDEC standard).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar synchronous step-down regulator applications.

Compared with MP2315DJ-LF-Z and TPS54331DR, ST1S10BPHR uniquely combines dual-VIN noise isolation, SYNC capability, and true 2.5 V start-up-making it optimal for compact, EMI-constrained, and multi-rail consumer electronics where reliability and thermal performance are prioritized over lowest BOM cost.

Availability

ST1S10BPHR is available at Aetrix Electronics and suitable for consumer audio power, FPGA core supply, LCD monitor backlights, and DSL modem DC-DC modules requiring stable component supply, full production lifecycle support, and guaranteed traceability.

Supply support for ST1S10BPHR 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, designing and manufacturing analog, mixed-signal, power, and microcontroller products for industrial, automotive, and consumer markets.

ST1S10BPHR belongs to ST's Power Management – DC-DC Converters product line, engineered specifically for high-efficiency, space-constrained point-of-load regulation in consumer electronics and industrial embedded systems where thermal performance and EMI control are critical.

FAQ

What is the minimum input voltage required for ST1S10BPHR to start switching?

The ST1S10BPHR features an under-voltage lockout (UVLO) with a rising threshold of 2.3 V and 200 mV hysteresis. It begins switching only when VIN_SW rises above 2.3 V, ensuring stable operation before regulation commences. This enables compatibility with partially discharged 3.3 V or 5 V rails and automotive cold-crank scenarios.

Can ST1S10BPHR operate with only ceramic output capacitors?

Yes-ST1S10BPHR is explicitly designed for ceramic output capacitors, with internal compensation optimized for low-ESR types. A minimum 22 µF X5R/X7R ceramic capacitor is recommended for V_OUT > 2.5 V; for lower outputs (e.g., 1.2 V), two parallel 22 µF units improve loop stability and transient response without requiring electrolytic supplementation.

How does the INH (EN) pin behave during power-up?

The INH pin is active-low with thresholds of 1.2 V (enable) and 0.4 V (disable), and draws only 2 µA. During power-up, if left floating, its internal pull-up ensures default enable-but for robust sequencing, tie INH to a controlled GPIO or RC-delayed rail to prevent premature startup before input stabilization or other system components are ready.

Is the exposed pad of the PowerSO-8 package electrically connected?

Yes-the exposed pad is internally connected to PGND and must be soldered to a dedicated PCB ground plane with ≥4 thermal vias (0.3 mm diameter) to achieve the specified R_thJA = 40 °C/W. Failure to connect the pad results in >30 °C higher junction temperature at 3 A load and potential thermal shutdown under sustained operation.