L6728ATR STMicroelectronics

L6728A High frequency single phase PWM controller with Power Good Features Flexible power supply from 5 V to 12 V Power conversion input as low as 1.5 V 0.8 V internal reference 0.8 % output voltage accuracy High-current integrated drivers VFQFPN 10 Power Good output Sensorless and programmable OCP across low-side R Description DS(on) OV / UV protections L6728A is a single-phase step-down controller VSEN disconnection protection with integrated high-current drivers that provides complete control logic and protection to realize in Oscillator internally fixed at 600 kHz a simple way general DC-DC converters by using LS-LESS to manage pre-bias start-up a compact VFDFPN 10 package. Adjustable output voltage Device flexibility allows managing conversions Disable function with power input V as low as 1.5 V and device IN supply voltage ranging from 5 V to 12 V. Internal soft-start VFDFPN 10 package L6728A provides simple control loop with voltage mode EA. The integrated 0.8 V reference allows regulating output voltages with 0.8 % accuracy over line and temperature variations. Oscillator is Applications internally fixed to 600 kHz. Memory and termination supply L6728A provides programmable dual level over current protection as well as over and under Subsystem power supply (MCH, IOCH, PCI) voltage protection. Current information is CPU and DSP power supply monitored across the low-side MOSFET R DS(on) Distributed power supply saving the use of expensive and space- consuming sense resistors. General DC / DC converters PGOOD output easily provides real-time information on output voltage status, through VSEN dedicated output monitor. Table 1. Device summary Order codes Package Packing L6728A VFDFPN 10 Tube L6728ATR VFDFPN 10 Tape and reel October 2008 Rev 1 1/32 www.st.com 1 Obsolete Product(s) - Obsolete Product(s) Obsolete Product(s) - Obsolete Product(s) L6728A Contents Contents 1 Typical application circuit and block diagram 4 1.1 Application circuit 4 1.2 Block diagram . 4 2 Pins description and connection diagrams 5 2.1 Pin descriptions . 5 2.2 Thermal data . 6 3 Electrical specifications 7 3.1 Absolute maximum ratings . 7 3.2 Electrical characteristics . 7 4 Device description 9 5 Driver section . 10 5.1 Power dissipation . 10 6 Soft-start . 11 6.1 Low-side-less start up (LSLess) 11 7 Over-current protection . 12 7.1 Over-current threshold setting . 12 8 Output voltage setting and protections 13 9 Application details . 14 9.1 Compensation network 14 9.2 Layout guidelines . 16 10 Application information . 18 10.1 Inductor design . 18 10.2 Output capacitor(s) 19 10.3 Input capacitors 19 2/32 Obsolete Product(s) - Obsolete Product(s) Obsolete Product(s) - Obsolete Product(s)