ST1S31

The ST1S31 device is an internally compensated 1.5 MHz fixed-frequency PWM synchronous step-down regulator. The ST1S31 operates from 2.8 V to 5.5 V input, while it regulates an output voltage as low as 0.8 V and up to V_IN.

The ST1S31 integrates a 60 mΩ high-side switch and a 45 mΩ synchronous rectifier allowing very high efficiency with very low output voltages.

The peak current mode control with internal compensation delivers a very compact solution with a minimum component count.

The ST1S31 device is available in 3 mm x 3 mm, 8 lead VFDFPN and SO8 packages.

Key Features

3 A DC output current
2.8 V to 5.5 V input voltage
Output voltage adjustable from 0.8 V
1.5 MHz switching frequency
Internal soft-start and enable
Integrated 60 mΩ and 45 mΩ power MOSFETs
All ceramic capacitor
Power Good (POR)
Cycle-by-cycle current limiting
Current foldback short-circuit protection
VFDFPN 3 x 3 - 8L, SO8 packages

Resources

Technical Documentation

Product Specifications

	Description	Version	Size
	DS8977: 3 A DC step-down switching regulator	5.0	1.5 MB

Publications and Collaterals

Brochures

Description	Version	Size
Brochure Power management guide	10.2018	4.42 MB
Electric vehicle (EV) ecosystem	1.1	1.28 MB
Switching Converters (DC-DC) – Quick Reference Guide	1.0	481.92 KB

Tools and Software

Evaluation Tools

Solution Evaluation Tools

Part Number	Manufacturer	Description
STEVAL-ISA069V1		3 A / 1.5 MHz step-down synchronous switching regulator based on the ST1S31 in DFN 3x3 package
STEVAL-ISA070V1		3 A / 1.5 MHz step-down synchronous switching regulator based on the ST1S31 in SO-8 package

Converter

DC/DC

Input

Volt. Min [V] This option is required. And must be less than or equal to Volt. Max [V]

Volt. Max [V] This option is required. And must be greater than or equal to Volt. Min [V]

Output

Output Power:

Voltage [V] This option is required and must be a number.

Current [A] This option is required and must be a number.

Sample & Buy

Part Number	Package	Packing Type	Marketing Status	Unit Price (US$) *	Quantity	ECCN (US)	Country of Origin	More info	Order from ST	Order from Distributors
ST1S31D-R	SO-8	Tape And Reel	Active : Product is in volume production	0.471	1000	EAR99	CHINA	MORE INFO	Free Sample Add to cart	DISTRIBUTOR AVAILABILITY
ST1S31PUR	VFDFPN 8 3x3x1.0	Tape And Reel	Active : Product is in volume production	0.535	1000	EAR99	MALAYSIA	MORE INFO	Free Sample Add to cart	DISTRIBUTOR AVAILABILITY

(*) Suggested Resale Price per unit (USD) for BUDGETARY USE ONLY. For quotes, prices in local currency, please contact your local ST Sales Office or our Distributors

Quality & Reliability

Part Number	Marketing Status	Package	Grade	RoHS Compliance Grade	Material Declaration**
ST1S31D-R	Active	SO-8	Industrial	Ecopack2
ST1S31PUR	Active	VFDFPN 8 3x3x1.0	Industrial	Ecopack2

(**) The Material Declaration forms available on st.com may be generic documents based on the most commonly used package within a package family. For this reason, they may not be 100% accurate for a specific device. Please contact our sales support for information on specific devices.