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STMicroelectronics ST1S31

3 A DC step-down switching regulator

Overview

TopologyBuck Converter
Switching frequency1200-1900 kHz
IC revision4

Description

The ST1S31 device is an internally compensated1.5 MHz fixed-frequency PWM synchronous stepdownregulator. The ST1S31 operates from 2.8 Vto 5.5 V input, while it regulates an output voltageas low as 0.8 V and up to VIN.The ST1S31 integrates a 60 m high-side switchand a 45 m synchronous rectifier allowing veryhigh efficiency with very low output voltages.The peak current mode control with internalcompensation delivers a very compact solutionwith a minimum component count.The ST1S31 device is available in 3 mm x 3 mm,8 lead VFDFPN and SO8 packages.

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 m and 45 m 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

Typical applications

  • μP/ASIC/DSP/FPGA core and I/O supplies, Optical storage, hard disk drive, printers, audio/graphic cards
  • Point of load for: STB, TVs, DVDs

Products

Order Code Data­sheet Downloads Product seriesL
(µH)
IR
(A)
ISAT
(A)
RDC typ.
(mΩ)
RDC max.
(mΩ)
fres
(MHz)
SizeVersionLR
(µH)
RDC
(mΩ)
Material Samples
744771001
IGS STP ALT EAG CAD LTS PSP SPE CADWE-PD SMT Power Inductor 1.5 10.5 12.5 4 6 60 1260 Standard
744310150
STE ALT EAG CAD LTS PSP SPE IGS CADWE-HCI SMT Flat Wire High Current Inductor 1.5 7.5 12 13.97 80 7030 SMT 1.25 12.7 Superflux
744311150
STE ALT EAG CAD LTS PSP SPE IGS CADWE-HCI SMT Flat Wire High Current Inductor 1.5 11 14 7.26 72 7040 SMT 1.12 6.6 Superflux
744310200
STE ALT EAG CAD LTS PSP SPE IGS CADWE-HCI SMT Flat Wire High Current Inductor 2 6.5 9 15.62 58 7030 SMT 1.55 14.2 Superflux
744771002
IGS STP ALT EAG CAD LTS PSP SPE CADWE-PD SMT Power Inductor 2.2 10 11 5 8 50 1260 Standard
744316220
STE ALT EAG CAD LTS PSP SPE IGS CADWE-HCI SMT Flat Wire High Current Inductor 2.2 7.5 7.5 11.3 12.43 108 5040 SMT 1.5 11.3 Superflux
7443551280
STE ALT EAG CAD LTS PSP SPE IGS CADWE-HCI SMT Flat Wire High Current Inductor 2.8 20 17.5 3.74 35 1365 SMT 1.85 3.3 WE-PERM
744314330
STE ALT EAG CAD LTS PSP SPE IGS CADWE-HCI SMT Flat Wire High Current Inductor 3.3 9 8 9.9 65 7050 SMT 2.2 9 Superflux
744771003
IGS STP ALT EAG CAD LTS PSP SPE CADWE-PD SMT Power Inductor 3.5 9.25 9 5 8 40 1260 Standard
7443556350
STE ALT EAG CAD LTS PSP SPE IGS CADWE-HCI SMT Flat Wire High Current Inductor 3.5 22.5 37 3.348 38 1890 SMT 3 3.1 WE-PERM 2
744325420
STE ALT EAG CAD LTS PSP SPE IGS CADWE-HCI SMT Flat Wire High Current Inductor 4.2 11 14 7.87 33 1050 SMT 3.3 7.1 Superflux
744316470
STE ALT EAG CAD LTS PSP SPE IGS CADWE-HCI SMT Flat Wire High Current Inductor 4.7 4.6 4.7 26.95 57 5040 SMT 3.3 24.5 Superflux
744311470
STE ALT EAG CAD LTS PSP SPE IGS CADWE-HCI SMT Flat Wire High Current Inductor 4.7 6 7 21.45 33 7040 SMT 3.5 19.5 Superflux
Samples
Order Code Data­sheet Downloads Product seriesL
(µH)
IR
(A)
ISAT
(A)
RDC typ.
(mΩ)
RDC max.
(mΩ)
fres
(MHz)
SizeVersionLR
(µH)
RDC
(mΩ)
Material Samples