ST1S40 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, DVD HSOP-8 SO8 Optical storage, hard disk drive, printers, audio/graphic cards VFQFPN 4 x 4 Description Features The ST1S40 device is an internally compensated 850 kHz fixed-frequency PWM synchronous step- 3 A DC output current down regulator. The ST1S40 operates from 4.0 V 4.0 V to 18 V input voltage to 18 V input, while it regulates an output voltage Output voltage adjustable from 0.8 V as low as 0.8 V and up to V . IN 850 kHz switching frequency The ST1S40 integrates a 95 m high side switch Internal soft-start and 69 m synchronous rectifier allowing very high efficiency with very low output voltages. Integrated 95 m and 69 m Power MOSFETs The peak current mode control with internal All ceramic capacitor compensation delivers a very compact solution Enable with a minimum component count. Cycle-by-cycle current limiting The ST1S40 is available in HSOP-8, VFQFPN 4 Current fold back short-circuit protection mm x 4 mm - 8 lead, and standard SO8 package. Available in HSOP-8, VFQFPN4x4-8L, and SO8 packages Figure 1. Application circuit / + 9 8 92 7 1 ,9 9 5 67 6 , ) )% &RXW Q VZ&L B 5 *1 3*1 H3DG ) ) August 2019 DocID17928 Rev 6 1/30 This is information on a product in full production. www.st.com (1 3* &LQBD 9,1 6: 9,16:Contents ST1S40 Contents 1 Pin settings 3 1.1 Pin connection 3 1.2 Pin description 3 2 Maximum ratings 4 3 Thermal data . 4 4 Electrical characteristics . 5 5 Functional description . 7 5.1 Internal soft-start 8 5.2 Error amplifier and control loop stability . 8 5.3 Overcurrent protection . 13 5.4 Enable function 13 5.5 Hysteretic thermal shutdown 13 6 Application information . 14 6.1 Input capacitor selection 14 6.2 Inductor selection . 15 6.3 Output capacitor selection 16 6.4 Thermal dissipation . 17 6.5 Layout consideration 18 7 Demonstration board . 20 8 Typical characteristics 22 9 Package information 23 10 Order codes . 28 11 Revision history . 29 2/30 DocID17928 Rev 6