A buck converter also called buck regulator or DC-DC step-down switching regulator, is a type of DC-DC converter which provides an output regulated voltage that is lower than its input voltage.
ST's monolithic step-down (buck) converter ICs offer input-voltage capability up to 61 V, deliver output currents up to 4 A, with high switching frequency. This broad portfolio of ICs is composed of highly-specialized products to meet every market requirement:
- High-voltage technology together with high reliability, robustness and compactness for industrial and automotive applications
- High efficiency at any load and a high level of performance for consumer and computer products
These buck regulators embed a full set of protection functions (overcurrent, overvoltage, over-temperature) to increase the MTBF and reduce the number of external components.
There are multiple package options, all offering compactness and high thermal performances.
Wide range of step-down (buck) switching regulators
Learn about ST broad selection of buck converters, designed to meet a wide range of application requirements.
Low quiescent current buck converter ICs
ST's low IQ buck converters are ideal for any power-budgeted applications, such as battery-powered devices or green-compliant equipment with long stand-by operation. Extend the battery life and reduce the overall power consumption of your industrial and automotive application designs.
Buck converters for Industrial applications

High reliability and excellent robustness buck converters, for industrial and any application requiring a wide range of input output voltages.
See all Industrial buck convertersBuck converters for Automotive applications

ST offers high performance and high flexibility AEC-Q100 compliant buck converters for automotive applications.
See all Automotive buck convertersFeatured Videos
38 V 1.5 A step-down converter with low quiescent current
The new L6981 is an easy-to-use regulator delivering high efficiency capability across all loads. The wide input voltage range (3.5 V - 38V) makes it the ideal solution for 24 V industrial bus-powered systems, HVAC power supplies, battery-powered equipment, decentralized intelligent nodes and always-on devices like smart sensors.
Housed in an SO8 package , the L6981 is based on peak current mode architecture with internal compensation to help reduce the overall size and complexity of the end-product designs.
Evaluation boards are available, to support developers in their designs.
STEVAL-L6981CDR ; STEVAL-L6981NDR
New 400 mA synchronous buck converters, with nano-quiescent current and very high efficiency, push performance beyond limits
Boasting a quiescent current of only 500 nA, ST’s miniaturized ST1PS01 and ST1PS02 step-down converters with digital voltage selection specifically address battery-powered and energy-harvesting applications, thanks also to their high efficiency over a wide range of operating conditions.
The integrated power switch and compensation network allow this new generation of step-down converters to work with only just a few external components.
Evaluation boards are available for both products, to support developers in their designs.
STEVAL-1PS01AJR ; STEVAL-1PS01DJR ; STEVAL-1PS01EJR ; STEVAL-1PS02B
New 61 V, 3 A step-down switching regulator for automotive application
Housed in a HTSSOP16-package, the A7987 is a 3 A step-down switching regulator with a wide input-voltage range, making it suitable for 24 V battery-powered applications.
Specifically recommended to design flexible and robust solutions, the A7987 also offers a set of additional functionalities including adjustable current limit, synchronization with a 180° phase shift, and power sequencing.
These key features ensure flexible and stable performance when several voltage rails are powered up in automotive applications such as body infotainment and telematics.
Large selection of step-down DC-DC regulators with synchronous rectification
In the quest for higher efficiency and compact form factor in their DC-DC supply designs, engineers now have a few more allies: the L6985F, L6986F and L6986 step-down DC-DC regulators with synchronous rectification and an output current of 0.5 A, 1,5 A and 2 A respectively.
Based on a peak current mode architecture with a p-channel power MOSFET, they feature a selectable low-consumption-mode (LCM burst mode) to increase efficiency at light load, and a low-noise-mode (LNM with fixed PWM switching frequency) for noise-sensitive designs.
An easy-to-use evaluation board (STEVAL-ISA156V1) based on the L6986 regulator is available to help you configure and evaluate application parameters so you can reach higher efficiency, higher power density and lower standby power designs.
- L5983 1.5 A step-down switching regulator
- L5985 2 A step-down switching regulator
- A7987 61 V 3A asynchronous step-down switching regulator with adjustable current limitation for automotive
- ST1PS01 400 mA nano-quiescent synchronous step-down converter with digital voltage selection and Power Good
- L5980 0.7 A step-down switching regulator
- L5981 1 A step-down switching regulator
- A5972D Up to 1.5 A step-down switching regulator for automotive applications
- A5973AD Up to 1.5 A step-down switching regulator for automotive applications
- A5970AD Up to 1 A step down switching regulator for automotive applications
- A5970D Up to 1 A step-down switching regulator for automotive applications
- A5973D Up to 2 A step down switching regulator for automotive applications
- A6902D Up to 1 A step down switching regulator with adjustable current limit for automotive applications
- AST1S31HF Up to 4 V, 3 A step-down 2.3 MHz switching regulator for automotive applications
- ST1S14 Up to 3 A step-down switching regulator
- ST1S30 3 A, 1.5 MHz PWM step-down switching regulator with synchronous rectification
- L4964 High current switching regulator
- A5974D Up to 2.5 A step down switching regulator for automotive applications
- L296 HIGH CURRENT SWITCHING REGULATORS
- B5973D 2 A step down switching regulator for automotive applications
- L7987 61 V 3 A asynchronous step-down switching regulator with adjustable current limitation
- STPD01 Programmable Buck Converter for USB Power Delivery
- A6986F Automotive 38 V, 1.5 A synchronous step-down switching regulator with 30 µA quiescent current
- L6986F 38 V, 1.5 A synchronous step-down switching regulator with 30 µA quiescent current
- ST1S15 500 mA, 6 MHz synchronous step-down converter
- A6984 36 V 400 mA synchronous step-down switching regulator
- ST1S06 Synchronous rectification with inhibit, 1.5 A, 1.5 MHz fixed or adjustable, step-down switching regulator
- L4972 2 A SWITCHING REGULATOR
- ST1S40 3 A DC step-down switching regulator
- L6926 High efficiency monolithic synchronous step-down regulator
- ST2S08B Dual synchronous rectification, 1.5 A, 1.5 MHz adjustable step-down switching regulator
- L5970AD Up to 1 A step down switching regulator
- A6985F Automotive 38 V, 500 mA synchronous step-down switching regulator with 30 µA quiescent current
- L6985F 38 V, 500 mA synchronous step-down switching regulator with 30 µA quiescent current
- PM8908 Monolithic buck converter for DDR memory termination
- ST1S32 4 A DC step-down switching regulator
- L6902 Up to 1 A switching regulator with adjustable current limit
- ST1S41 4 A step-down switching regulator
- ST2S06 Dual synchronous rectification with reset or inhibit, 0.5 A, 1.5 MHz adjustable step-down switching regulator
- ST1S09 2 A, 1.5 MHz PWM step-down switching regulator with synchronous rectification
- L7983 60 V 300 mA synchronous step-down switching regulator with 10 µA quiescent current
- L6983 38 V, 3 A synchronous step-down converter with 17 µA quiescent current
- L5973D Up to 2 A step down switching regulator
- L5972D 2A switch step down switching regulator
- L7981 3 A step-down switching regulator
- L7980 2 A step-down switching regulator
- ST1S31 3 A DC step-down switching regulator
- L6984 36 V, 400 mA synchronous step-down switching regulator
- L6986 38 V, 2 A synchronous step-down switching regulator with 30 µA quiescent current
- PM8903A 3 A step-down monolithic switching regulator
- A6986I Automotive 38 V, 5W synchronous iso-buck converter
- L5988D 4 A continuous (more than 5 A pulsed) step-down switching regulator with synchronous rectification
- L6986H 38 V, 2 A synchronous step-down switching regulator with 30 µA quiescent current
- L5970D Up to 1 A step down switching regulator
- AST1S31 Up to 4 V, 3 A step-down 1.5 MHz switching regulator for automotive applications
- L4978 2A Step down switching regulator
- ST1S50 4 A Monolithic synchronous step-down converter with high efficiency at light load
- L5973AD 2 A switch step down switching regulator
- ST1PS02 400 mA nano-quiescent synchronous step-down converter with digital voltage selection, Power Good and AUX switch
- L4976 1 A step down switching regulator
- A6986H Automotive 38 V, 2 A synchronous step-down switching regulator with 30 µA quiescent current
- A5974AD Up to 2 A step-down switching regulator for automotive applications
- A5975D Up to 3 A step down switching regulator for automotive applications
- A5975AD Up to 2.5 A step down switching regulator for automotive applications
- ST1S03 1.5 A, 1.5 MHz adjustable, step-down switching regulator
- L4973 3.5 A step down switching regulator
- ST1S10 3 A, 900 kHz, monolithic synchronous step-down regulator IC
- L4974A 3.5 A switching regulator
- L4971 1.5A Switching Regulator
- L4970A 10 A switching regulator
- L4963 1.5 A SWITCHING REGULATOR
- ST1S12XX Synchronous rectification with enable, 0.7 A, 1.7 MHz fixed or adjustable step-down switching regulator in TSOT23-5L
- A7986A 3 A step-down switching regulator for automotive applications
- A7985A 2 A step-down switching regulator for automotive applications
- L4975A 5 A switching regulator
- L6981 38 V, 1.5 A synchronous step-down converter with low quiescent current
- L5986 2.5 A step-down switching regulator
- L5987 3 A step-down switching regulator
- A6986 38 V, 2 A synchronous step-down switching regulator with 30 µA quiescent current
- L7987L 61 V 2 A asynchronous step-down switching regulator with adjustable current limitation
- L7985 2 A step-down switching regulator
- L7986TA 3 A step-down switching regulator
- L7986 3 A step-down switching regulator
- L6928 High efficiency monolithic synchronous step-down regulator