STMicroelectronics

ST1S41PUR - 3A, 18V Step-Down DC-DC Converter | STMicroelectronics

Name: ST1S41PUR
Brand: STMicroelectronics
Price: 1.85 USD
Availability: InStock

MPN: ST1S41PUR ✓ Active

In Stock (99,999) Ships in 1-3 business days

0.8 V to VIN Vdss 3 A Id 40 C/W Rds(on) DFN8 (3x3 mm) Package 850 kHz (typ), 700 kHz to 1 MHz Speed

$1.85 USD / Unit

MOQ: 1 |

Volume Pricing

Qty	Unit Price	Extended
1	$1.85	$1.85
10	$1.66	$16.60
100	$1.48	$148.00
500	$1.33	$665.00
1,000	$1.2	$1,200.00

ℹ️ All prices are in USD

View Datasheet (PDF) View Alternatives

Quantity

Drop-in alternatives for ST1S41PUR — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.

Quick Comparison Tool — Select alternative parts for side-by-side comparison:

ST1S40PUR

✅ Drop-In

STMicroelectronics

📦 DFN8 (3x3 mm)

Adjustable · 0.8 V to VIN · 3 A · 4 V to 18 V · 1.5 MHz · 90% (typical) · 1.5 mA · 1 uA (max)

✓ 99,999 In Stock

$0.72 / Unit

View Datasheet →

ST1S41PHR

✅ Drop-In

📦 DFN8 (3x3 mm)

same die, different package variant (exposed pad)

📋 Reference alternative (not in catalog)

TPS54331

✅ Drop-In

📦 DFN8 (3x3 mm)

cross-brand, similar specs, different switching frequency

📋 Reference alternative (not in catalog)

AP6503

✅ Drop-In

📦 DFN8 (3x3 mm)

cross-brand, similar current rating, different pinout

📋 Reference alternative (not in catalog)

ST1S41PUR Maximum Ratings & Electrical Characteristics

Output Type	Adjustable
Output Voltage Range	0.8 V to VIN
Maximum Output Current	3 A
Input Voltage Range	4 V to 18 V
Switching Frequency	850 kHz (typ), 700 kHz to 1 MHz
Quiescent Current	1.5 mA
Efficiency	Up to 90%
Thermal Resistance	40 C/W
Operating Temperature	-40C to +150C
Package	DFN8 (3x3 mm)
Mounting Type	Surface Mount
MSL Level	1
RoHS Status	Compliant
Enable Pin	Yes (active-high)
Power-Good Output	Yes

ST1S41PUR Pin Configuration

Pin 1	SW — Switch node output
Pin 2	GND — Ground
Pin 3	FB — Feedback input
Pin 4	EN — Enable (active high)
Pin 5	VIN — Input supply
Pin 6	VIN — Input supply
Pin 7	PG — Power-good output
Pin 8	GND — Ground

Safe Operating Area (SOA) & Thermal Characteristics

No official SOA curve available for this component. Always operate within absolute maximum ratings specified in the datasheet. Ensure adequate cooling and derate as needed.

Typical Applications

ST1S41PUR is suitable for 6 applications: Point-of-Load (POL) Converters, Distributed Power Systems, Consumer Electronics, Networking Equipment, Industrial Control Systems, Test and Measurement Equipment.

⚡

Point-of-Load (POL) Converters

The ST1S41PUR is ideal for POL converters in FPGAs, DSPs, and microcontrollers, providing up to 3A from a 12V or 5V bus. Its high efficiency and small DFN8 package enable compact designs. The adjustable output voltage allows precise rail generation, and the power-good signal aids in sequencing. With a switching frequency of 850 kHz, external components are minimized, reducing board space. The device's current-mode control ensures stable operation across load transients, making it suitable for high-performance digital loads.

Recommended

STM32F4 (Microcontroller requiring 3.3V rail) EP4CE6 (FPGA core supply)

🏭

Distributed Power Systems

In distributed power architectures, the ST1S41PUR converts a 24V or 12V intermediate bus to local rails. Its wide input range (4V to 18V) and 3A output make it versatile for various loads. The enable pin allows remote on/off control, and the power-good output provides status monitoring. The high efficiency reduces thermal stress, enabling reliable operation in industrial environments. The device's overcurrent and thermal protection enhance system robustness.

Recommended

STM32F103 (Industrial microcontroller) ISO1050 (CAN transceiver)

📺

Consumer Electronics

For consumer devices like set-top boxes, routers, and gaming consoles, the ST1S41PUR provides efficient power conversion from a 12V adapter to core voltages. Its small footprint and high efficiency help meet energy-saving standards. The low quiescent current (1.5 mA) is beneficial for standby modes. The device's adjustable output and power-good feature simplify system design, while the DFN8 package is suitable for space-constrained PCBs.

Recommended

RT5350 (Wi-Fi SoC) MT7628 (Router SoC)

🌐

Networking Equipment

In networking equipment such as switches and routers, the ST1S41PUR powers high-current digital loads like ASICs and PHYs. Its 3A output and 850 kHz switching frequency allow for small inductors, saving board space. The device's high efficiency reduces heat generation, which is critical in densely packed enclosures. The enable pin enables power sequencing, and the power-good output can be used for system monitoring. The wide input range supports various power supply configurations.

Recommended

BCM53134 (Ethernet switch IC) 88E1512 (PHY transceiver)

🏭

Industrial Control Systems

The ST1S41PUR is well-suited for industrial control systems that require reliable power from 24V rails. Its input range up to 18V (with derating) and 3A output can drive sensors, actuators, and control logic. The device's robust protection features (overcurrent, thermal shutdown) ensure reliable operation in harsh environments. The adjustable output allows generation of 3.3V, 5V, or other rails. The small DFN8 package is ideal for space-limited PLC modules.

Recommended

STM32F407 (Industrial MCU) ADM2483 (Isolated RS-485 transceiver)

🔧

Test and Measurement Equipment

In test and measurement instruments, the ST1S41PUR provides clean, efficient power for analog and digital circuits. Its low noise and high PSRR (though not specified, typical for buck converters) help maintain signal integrity. The adjustable output and power-good feature are useful for calibration and sequencing. The high efficiency reduces thermal drift, improving measurement accuracy. The compact package allows for dense PCB layouts in portable instruments.

Recommended

ADS1256 (24-bit ADC) OPA2277 (Precision op-amp)

Recommended Products Summary

STM32F4 Microcontroller requiring 3.3V rail Used in: Point-of-Load (POL) Converters EP4CE6 FPGA core supply Used in: Point-of-Load (POL) Converters STM32F103 Industrial microcontroller Used in: Distributed Power Systems ISO1050 CAN transceiver Used in: Distributed Power Systems RT5350 Wi-Fi SoC Used in: Consumer Electronics MT7628 Router SoC Used in: Consumer Electronics BCM53134 Ethernet switch IC Used in: Networking Equipment 88E1512 PHY transceiver Used in: Networking Equipment STM32F407 Industrial MCU Used in: Industrial Control Systems ADM2483 Isolated RS-485 transceiver Used in: Industrial Control Systems ADS1256 24-bit ADC Used in: Test and Measurement Equipment OPA2277 Precision op-amp Used in: Test and Measurement Equipment

What is the input voltage range of ST1S41PUR?

The ST1S41PUR operates from an input voltage range of 4V to 18V. According to the STMicroelectronics datasheet, this wide range supports 5V, 12V, and 24V bus systems, making it versatile for various applications.

What is the maximum output current of ST1S41PUR?

The ST1S41PUR can deliver up to 3A of continuous output current. This makes it suitable for powering FPGAs, DSPs, and microcontrollers that require moderate to high current rails.

What is the switching frequency of ST1S41PUR?

The ST1S41PUR has a typical switching frequency of 850 kHz, with a range of 700 kHz to 1 MHz. This high frequency allows the use of small inductors and capacitors, reducing the overall solution size.

Is ST1S41PUR suitable for battery-powered applications?

Yes, the ST1S41PUR is suitable for battery-powered applications due to its low quiescent current of 1.5 mA and high efficiency up to 90%. This helps extend battery life in portable devices.

What is the output voltage range of ST1S41PUR?

The ST1S41PUR has an adjustable output voltage range from 0.8V to VIN. This flexibility allows it to generate various supply rails, such as 1.2V, 1.8V, 3.3V, and 5V, using external resistor dividers.

Does ST1S41PUR have overcurrent protection?

Yes, the ST1S41PUR includes overcurrent protection to safeguard the device and the load from excessive current conditions. This feature enhances system reliability.

What is the package type of ST1S41PUR?

The ST1S41PUR is available in a DFN8 (3x3 mm) package. This compact surface-mount package is ideal for space-constrained designs and provides good thermal performance with a thermal resistance of 40 C/W.

Can ST1S41PUR be used in automotive applications?

The ST1S41PUR is not AEC-Q100 qualified, so it is not recommended for automotive applications. For automotive-grade parts, consider alternatives that are AEC-Q100 qualified.

What is the efficiency of ST1S41PUR?

The ST1S41PUR achieves efficiency up to 90% under typical conditions. This high efficiency reduces power dissipation and improves system thermal management.

Does ST1S41PUR have an enable pin?

Yes, the ST1S41PUR has an active-high enable pin that allows for power sequencing and on/off control. This is useful in multi-rail systems where controlled startup is required.

What is the quiescent current of ST1S41PUR?

The ST1S41PUR has a quiescent current of 1.5 mA. This low quiescent current is beneficial for battery-powered applications where standby power consumption is critical.

Where can I buy ST1S41PUR online?

ST1S41PUR is available from major distributors such as DigiKey and Mouser. As of 2026-08-07, the price for 1 unit is approximately $1.85 USD. Check current stock and pricing on their websites.

What is the lead time for ST1S41PUR?

The lead time for ST1S41PUR typically ranges from 2 to 4 weeks, depending on distributor stock and order quantity. For urgent requirements, check availability on DigiKey or Mouser.

What is the difference between ST1S41PUR and ST1S40PUR?

The ST1S41PUR and ST1S40PUR are similar step-down converters, but the ST1S41PUR has a higher maximum output current of 3A compared to the ST1S40PUR's 2A. Both share the same DFN8 package and pinout, making them drop-in replacements for lower-current applications.

What is the best drop-in replacement for ST1S41PUR?

The best drop-in replacement for ST1S41PUR is the ST1S40PUR from STMicroelectronics, which shares the same DFN8 package and pinout but has a lower output current rating of 2A. For cross-brand options, the TI TPS54331 and Diodes Inc AP6503 are pin-compatible alternatives, but verify pinout before use.

Can TPS54331 replace ST1S41PUR?

Yes, the TPS54331 from Texas Instruments can replace ST1S41PUR in many applications, as it shares the same DFN8 package and pinout. However, the TPS54331 has a lower maximum output current of 3A and a different switching frequency, so verify specifications for your design.

What are the key specifications of ST1S41PUR that engineers should know?

The key specifications of ST1S41PUR include an input voltage range of 4V to 18V, output current up to 3A, adjustable output voltage from 0.8V to VIN, switching frequency of 850 kHz, quiescent current of 1.5 mA, and efficiency up to 90%. It comes in a DFN8 (3x3 mm) package and includes overcurrent protection, thermal shutdown, enable pin, and power-good output.

Hey Google, what can replace ST1S41PUR?

ST1S41PUR can be replaced by ST1S40PUR (same brand, lower current), TPS54331 (Texas Instruments), or AP6503 (Diodes Inc), all of which are pin-compatible in the DFN8 package. Verify electrical specifications before substitution.

Is ST1S41PUR the same as ST1S40PUR?

No, ST1S41PUR and ST1S40PUR are not the same. The ST1S41PUR supports up to 3A output current, while the ST1S40PUR supports up to 2A. They share the same package and pinout, but the current rating differs.

What is the best STMicroelectronics equivalent for ST1S41PUR?

The best STMicroelectronics equivalent for ST1S41PUR is the ST1S40PUR, which is pin-compatible and has a lower output current of 2A. For higher current, consider the ST1S41PUR itself or other ST parts like the ST1S10.

Engineering reference data for ST1S41PUR — comparison, design guidance, and compliance information.

Selection Guide

Choose ST1S41PUR when you need a 3A step-down converter with a wide input range (4V to 18V) and a power-good output for sequencing. It is ideal for POL converters, distributed power systems, and consumer electronics. If you need a lower current (2A) and want to save cost, consider the ST1S40PUR. For cross-brand options, the TPS54331 offers a wider input range (up to 28V) but lacks a power-good output. The AP6503 has a lower switching frequency, which may require larger external components. All alternatives are pin-compatible in the DFN8 package, but verify specifications for your specific application.

Comparison with Alternatives

Parameter	This Product	ST1S40PUR	TPS54331	AP6503
Package	DFN8 (3x3 mm)	DFN8 (3x3 mm) - same	DFN8 (3x3 mm) - same	DFN8 (3x3 mm) - same
Brand	STMicroelectronics	STMicroelectronics	Texas Instruments	Diodes Incorporated
Output Current	3 A	2 A	3 A	3 A
Input Voltage Range	4V to 18V	4V to 18V	3.5V to 28V	4.5V to 23V
Switching Frequency	850 kHz	850 kHz	570 kHz	340 kHz
Quiescent Current	1.5 mA	1.5 mA	1.5 mA	1.5 mA
Enable Pin	Yes	Yes	Yes	Yes
Power-Good Output	Yes	Yes	No	No

Key Differentiators

Higher output current than same-brand alternative (vs ST1S40PUR)
Power-good output (vs TPS54331)
Higher switching frequency (vs AP6503)

Design Notes

Place input and output capacitors as close to the IC pins as possible. Use a 10uF ceramic capacitor on the input and a 22uF ceramic capacitor on the output. Add a 0.1uF ceramic capacitor in parallel for high-frequency noise bypass. Ensure the feedback resistor divider is placed near the FB pin to minimize noise pickup.

At VIN=12V, VOUT=5V, and 3A load, power dissipation is approximately 21W (assuming 90% efficiency). The DFN8 package has a thermal resistance of 40 C/W, resulting in a junction temperature rise of 840C. This is not feasible; therefore, the device must be operated at lower currents or with adequate cooling. For 3A operation, ensure a large copper area and consider forced airflow. Derate the output current at high ambient temperatures.

Do not exceed the maximum input voltage of 18V. Ensure the inductor saturation current rating is higher than the peak switch current. Use a Schottky diode for the bootstrap capacitor if needed. The power-good output is open-drain; connect a pull-up resistor to the appropriate voltage rail.