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Home > Products > Integrated Circuits (ICs) > Power Management (PMIC) > Voltage Regulators - DC DC Switching Regulators

STMicroelectronics ST1S03PMR

Name: ST1S03PMR
Brand: STMicroelectronics
SKU: ST1S03PMR
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: ST1S03PMR

Manufacturer:: STMicroelectronics

Category:: Voltage Regulators - DC DC Switching Regulators

Package:: 6-VDFN Exposed Pad

Datasheet:: ST1S03PMR.pdf

Description:: IC REG BUCK ADJ 1.5A 6DFN

Quantity:: RFQ Add To RFQ list

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Inventory:4,184

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Product details

Overview

ST1S03PMR from STMicroelectronics is a 1.5A, 1.5 MHz adjustable step-down switching regulator in DFN6 (3×3 mm) package, featuring current-mode PWM control, 2% DC output voltage tolerance, internal soft-start (50–100 µs), and thermal shutdown at 130–150°C. It delivers up to 1.5A across 3V–16V input for powering low-voltage digital cores in HDD systems.

For engineers reviewing the ST1S03PMR datasheet, ST1S03PMR pinout, ST1S03PMR application, or ST1S03PMR equivalent, key selection factors include its adjustable output via external resistor divider (V_OUT = 0.8 V × [1 + R1/R2]), 350 mV max switch V_DS at 750 mA, 70% typical efficiency, and DFN6 thermal resistance (R_thJA = 55 °C/W).

Technical Context

The ST1S03PMR implements a fixed-frequency (1.5 MHz) current-mode PWM architecture with internal compensation, enabling stable regulation using only ceramic capacitors and eliminating need for external loop compensation components. Its error amplifier features 300 kHz bandwidth and ±1 mA common-mode input range.

It integrates dual power supply rails: VIN_SW powers the MOSFET switch, while VIN_A supplies the analog control circuitry-enabling independent optimization of switching and bias paths. Protection includes cycle-by-cycle current limiting (1.65 A trip), thermal shutdown with 15°C hysteresis, and non-switching quiescent current ≤2.5 mA over temperature.

Key Specifications

Parameter	Value and Actual Design Meaning
Output current	1.5 A continuous - supports high-current digital core loads without external pass devices
Switching frequency	1.5 MHz (±20%) - enables use of compact 3.3 µH inductors and small ceramic capacitors
Feedback voltage	0.800 V (±2%) - sets precise output via external resistor divider; defines V_OUT = 0.8 × (1 + R1/R2)
Switch R_DS(on)	350 mV max @ 750 mA - limits conduction loss and self-heating during high-current operation
Quiescent current	2.5 mA max (non-switching) - minimizes standby power draw in always-on subsystems
Thermal shutdown	130–150°C junction threshold - protects against sustained overload or poor PCB thermal design
Efficiency	70% typical across 10 mA–1.2 A load - balances performance and component count in space-constrained HDD applications

Pinout & Package

ST1S03PMR is housed in a thermally enhanced DFN6 (3×3 mm, 0.75 mm height) package with exposed thermal pad. The package complies with ECOPACK® environmental standards and supports reflow soldering per JEDEC J-STD-020.

Pin/Terminal	Circuit Role	Design Meaning
1 - VFB	Feedback input	Monitors output voltage via resistor divider; internal reference is 0.8 V
2 - GND	System ground	Common return for analog and power sections; must be low-impedance connection to thermal pad
3 - SW	Switch node	Drives external Schottky diode and LC filter; carries high di/dt switching current
4 - VIN_SW	Switch supply rail	Powers internal MOSFET; decoupled separately from analog rail to reduce noise coupling
5 - VIN_A	Analog supply rail	Powers control circuitry including error amplifier and PWM comparator; improves PSRR
6 - N.C.	No connect	Unbonded terminal; must remain unconnected and unpopulated on PCB

Key Features

Feature	Design Value
Internal soft-start	50–100 µs power-on delay - prevents inrush current and stabilizes startup under varying input conditions
Current-mode PWM	300 kHz error amplifier bandwidth - ensures fast transient response and inherent cycle-by-cycle current limiting
Ceramic capacitor compatible	Stable with X5R/X7R MLCCs - eliminates need for high-ESR electrolytics and reduces board area
Dual supply inputs	VIN_SW and VIN_A separation - isolates noisy switch node from sensitive analog control, improving regulation accuracy
Thermal protection	Hysteresis of 15°C - prevents thermal oscillation during overload recovery and enables safe restart

Applications

HDD Digital Core Supply

Set-Top Box SoC Rail

Use Scenario: Powers 1.2 V/1.5 A digital core of 2.5-inch HDD controller ASIC under variable mechanical load and ambient temperature.

IC Role / Device Role / Timing Role: Primary step-down regulator delivering tightly regulated core voltage with minimal ripple (<50 mV_pp) using 22 µF ceramic output cap.

Use Value: Replaces linear regulator to eliminate >3 W thermal dissipation in sealed drive enclosure, extending reliability and reducing cooling requirements.

Use Scenario: Supplies configurable I/O voltage (1.8 V or 2.5 V) to media processor in consumer set-top box with bursty video decode workloads.

IC Role / Device Role / Timing Role: Adjustable buck converter supporting dynamic voltage scaling; responds to load transients <100 ns via current-mode control.

Use Value: Maintains ±1% output regulation during 100 mA → 1.2 A load steps, preventing logic errors during MPEG-4 frame decoding bursts.

Industrial PLC I/O Module

Network Attached Storage (NAS) Controller

Use Scenario: Generates isolated 3.3 V rail for microcontroller and CAN transceiver in DIN-rail mounted PLC with wide input range (12–24 VDC).

IC Role / Device Role / Timing Role: Input-flexible buck stage accepting 3–16 V; uses external resistor divider to fix 3.3 V output with 2% tolerance.

Use Value: Operates continuously at 85°C ambient due to DFN6 thermal pad and R_thJA = 55 °C/W, avoiding derating in enclosed enclosures.

Use Scenario: Provides 1.1 V core supply to ARM-based NAS SoC handling concurrent RAID 5 rebuild and SMB file serving.

IC Role / Device Role / Timing Role: High-efficiency (70%+) point-of-load regulator minimizing heat generation near NAND flash and SATA PHYs.

Use Value: Enables use of 3.3 µH inductor and avoids thermal throttling during sustained 1.5 A CPU load, preserving throughput during background tasks.

Equivalent & Alternatives

The following parts are listed as comparable options for similar adjustable buck regulator applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
TPS54302DDCR	Higher 2.5 A rating, 2.5 MHz switching, integrated high-side FET only (no external diode required)	Requires fewer external components but needs higher gate drive capability; less suitable for ultra-low-cost HDD designs	Preferred when board space is critical and cost premium acceptable for reduced BOM count
MP2307DN-LF-Z	1.2 A output, 340 mV typical R_DS(on), no separate VIN_A/VIN_SW rails	Simpler layout but lower PSRR and less robust under mixed-signal noise; lacks dual-supply isolation	Appropriate for cost-sensitive consumer electronics where analog noise immunity is secondary

Compared with TPS54302DDCR and MP2307DN-LF-Z, ST1S03PMR uniquely provides dual supply rails (VIN_A/VIN_SW), 1.5 A capability with proven HDD qualification history, and compatibility with legacy 3.3 µH inductor footprints-making it optimal for industrial storage upgrades requiring minimal redesign.

Availability

ST1S03PMR is available at Aetrix Electronics and suitable for HDD controller power delivery, set-top box SoC rails, and industrial PLC I/O modules requiring stable component supply, long-lifecycle support, and DFN6 thermal performance.

Supply support for ST1S03PMR 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 silicon solutions for automotive, industrial, and consumer markets since 1987.

The ST1S03 belongs to ST's Power Management IC portfolio targeting high-efficiency, space-constrained DC-DC conversion in storage and embedded computing-designed specifically to replace linear regulators in thermally demanding HDD and SoC applications.

FAQ

What is the minimum recommended output capacitor for ST1S03PMR?

The datasheet specifies 22 µF ceramic (X5R/X7R) as the standard output capacitor for typical applications. Lower values down to 10 µF are permissible if output ripple remains within system specification, but stability margin decreases below 15 µF due to reduced phase margin in the current-mode loop.

Can ST1S03PMR operate with only VIN_SW connected and VIN_A left open?

No. Both VIN_SW and VIN_A must be independently decoupled and powered. Leaving VIN_A unconnected disables the error amplifier and PWM comparator, halting regulation. The analog rail requires ≥2.7 V and must be sourced separately from the switch rail to maintain PSRR and startup integrity.

Does ST1S03PMR require an external Schottky diode in all configurations?

Yes. Unlike synchronous buck converters, ST1S03PMR uses an internal N-channel MOSFET switch and requires an external Schottky diode (e.g., STPS1L30) for freewheeling path. Omitting it causes catastrophic failure due to lack of current recirculation during off-time.

How does pulse-skipping mode affect light-load efficiency?

Below ~10 mA output, ST1S03PMR enters pulse-skipping mode to maintain regulation, reducing switching losses but increasing output voltage ripple (up to 2% peak-to-peak). Efficiency drops to ~45% at 1 mA, but quiescent current remains ≤2.5 mA, making it suitable for always-on monitoring circuits.

ST1S03PMR Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: 6-VDFN Exposed Pad

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Function:: Step-Down

Output Configuration:: Positive

Topology:: Buck

Output Type:: Adjustable

Number of Outputs:: 1

Voltage - Input (Min):: 3V

Voltage - Input (Max):: 16V

Voltage - Output (Min/Fixed):: 0.8V

Voltage - Output (Max):: 13.92V

Current - Output:: 1.5A

Frequency - Switching:: 1.5MHz

Synchronous Rectifier:: No

Operating Temperature:: 0°C ~ 125°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 6-DFN-EP (3x3)

ST1S03PMR FAQ

1.How can I place an order for ST1S03PMR through Aetrix?

Please submit a Request for Quotation (RFQ) for ST1S03PMR on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for ST1S03PMR reliable?

The price and inventory of ST1S03PMR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ST1S03PMR is usually 5 days.

3.What payment methods are accepted for ST1S03PMR?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ST1S03PMR transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for ST1S03PMR?

ST1S03PMR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your ST1S03PMR order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for ST1S03PMR?

For technical support, including ST1S03PMR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ST1S03PMR requirements.

6.How does Aetrix verify that ST1S03PMR is sourced from the original manufacturer or authorized distributors?

All ST1S03PMR products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that ST1S03PMR meets industry standards.

7.What is the process for return or replacement of ST1S03PMR?

All ST1S03PMR units undergo pre-shipment inspection (PSI). If there is an issue with ST1S03PMR, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The ST1S03PMR part is unused and in its original packaging.

Return procedure for ST1S03PMR:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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