ST1S31PUR STMicroelectronics

ST1S31 3 A DC step-down switching regulator Datasheet - production data Applications P/ASIC/DSP/FPGA core and I/O supplies Point of load for: STB, TVs, DVDs Optical storage, hard disk drive, printers, audio/graphic cards VFDFPN 3 x 3 - 8L SO8 Description The ST1S31 device is an internally compensated Features 1.5 MHz fixed-frequency PWM synchronous step- down regulator. The ST1S31 operates from 2.8 V 3 A DC output current to 5.5 V input, while it regulates an output voltage 2.8 V to 5.5 V input voltage as low as 0.8 V and up to V . IN Output voltage adjustable from 0.8 V The ST1S31 integrates a 60 m high-side switch 1.5 MHz switching frequency and a 45 m synchronous rectifier allowing very high efficiency with very low output voltages. Internal soft-start and enable Integrated 60 m and 45 m power MOSFETs The peak current mode control with internal compensation delivers a very compact solution All ceramic capacitor with a minimum component count. Power Good (POR) The ST1S31 device is available in 3 mm x 3 mm, Cycle-by-cycle current limiting 8 lead VFDFPN and SO8 packages. Current foldback short-circuit protection VFDFPN 3 x 3 - 8L, SO8 packages Figure 1. Application circuit / 1 928 7 6 :9,1 6: 9,1 5 &LQBD 67 6 (1 &RX W 3* Z QBV & L 5 August 2018 DocID022998 Rev 5 1/36 This is information on a product in full production. www.st.com *1 9)% 9,Contents ST1S31 Contents 1 Pin settings 4 1.1 Pin connection 4 1.2 Pin description 4 2 Maximum ratings 5 Thermal data 5 3 Electrical characteristics . 6 4 Functional description . 8 4.1 Output voltage adjustment . 9 4.2 Soft-start . 9 4.3 Error amplifier and control loop stability 10 4.4 Overcurrent protection . 14 4.5 Enable function 15 4.6 Light load operation . 15 4.7 Hysteretic thermal shutdown 15 5 Application information . 16 5.1 Input capacitor selection 16 5.2 Inductor selection . 17 5.3 Output capacitor selection 18 5.4 Thermal dissipation . 19 5.5 Layout consideration 20 6 Demonstration board . 22 7 Typical characteristics 24 8 Package information 30 8.1 VFDFPN 3 x 3 - 8L package information . 31 8.2 SO8 package information . 33 2/36 DocID022998 Rev 5