L6727TR STMicroelectronics

L6727 Single phase PWM controller Feature Flexible power supply from 5 V to 12 V Power conversion input as low as 1.5 V 1 % output voltage accuracy High-current integrated drivers SO-8 Adjustable output voltage 0.8 V internal reference Simple voltage mode control loop Description Sensorless and programmable OCP across L6727 is a single-phase step-down controller with Low-side R dsON integrated high-current drivers that provides Oscillator internally fixed at 300 kHz complete control logic, protections and reference voltage to realize in an easy and simple way Internal Soft-start general DC-DC converters by using a compact LS-LESS to manage pre-bias start-up SO-8 package. Disable function Device flexibility allows managing conversions OV / UV protection with power input V as low as 1.5 V and device IN supply voltage in the range of 5 V to 12 V. FB disconnection protection SO-8 package L6727 provides simple control loop with voltage- mode error-amplifier. The integrated 0.8 V reference allows regulating output voltages with Applications 1 % accuracy over line and temperature variations. Oscillator is internally fixed to 300 kHz. Subsystem power supply (MCH, IOCH, PCI...) Memory and termination supply L6727 provides programmable over current protection as well as over and under voltage CPU and DSP power supply protection. Current information is monitored Distributed power supply across the low-side MOSFET R saving the dsON General DC / DC converters use of expensive and space-consuming sense resistors while output voltage is monitored through FB pin. FB disconnection protection prevents excessive and dangerous output voltages in case of floating FB pin. Table 1. Device summary Order codes Package Packaging L6727 Tube SO-8 L6727TR Tape and reel March 2010 Doc ID 12933 Rev 4 1/34 www.st.com 34Contents L6727 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 6 3.1 Absolute maximum ratings . 6 3.2 Electrical characteristics . 7 4 Device description 9 5 Driver section . 10 5.1 Power dissipation . 10 6 Soft-start and disable . 11 6.1 Low-side-less start up (LSLess) 11 6.2 Enable / disable 12 7 Overcurrent protection 13 7.1 Overcurrent threshold setting 13 8 Output voltage monitor and protections 14 8.1 Undervoltage protection 14 8.2 Overvoltage protection . 14 8.3 Feedback disconnection protection . 14 8.4 Undervoltage lock out 14 9 Application details . 15 9.1 Output voltage selection 15 9.2 Compensation network 15 2/34 Doc ID 12933 Rev 4