L6738ATR STMicroelectronics

L6738A Single-phase PWM controller with light-load efficiency optimization Features Flexible power supply from 5 V to 12 V bus Power conversion input as low as 1.5 V Light-load efficiency optimization Embedded bootstrap diode VIN detector 0.8 V internal reference 0.5% output voltage accuracy VFQFPN16 Remote GND recovery and the device supply voltage ranging from 5 V to High-current integrated drivers 12 V bus. Sensorless and programmable precise-OC The L6738A features a proprietary algorithm that sense across Inductor DCR allows Light-Load efficiency optimization, OV protection boosting efficiency without compromising the output voltage ripple. Programmable oscillator up to 600 kHz LS-less to manage pre-bias startup The integrated 0.8 V reference allows generation of output voltages with 0.5% accuracy over line Adjustable output voltage and temperature variations. Disable function The oscillator is programmable up to 600 kHz. Internal soft-start The L6738A provides a programmable VFQFPN 16 3x3 mm package overcurrent protection and overvoltage protection. The current information is monitored across the Applications inductor DCR. Memory and termination supply The L6738A is available in a VFQFPN 16 3x3 mm package. Subsystem power supply (MCH, IOCH, PCI) CPU and DSP power supply Table 1. Device summary Distributed power supply Order code Package Packing General DC-DC converter L6738A VFQFPN16 Tube L6738ATR VFQFPN16 Tape and reel Description The L6738A is a single-phase step-down controller with integrated high-current drivers that provides complete control logic and protection to realize a DC-DC converter. The device flexibility allows to manage conversions with power input V as low as 1.5V IN January 2012 Doc ID 18134 Rev 2 1/32 www.st.com 32Contents L6738A Contents 1 Typical application circuit and block diagram 5 1.1 Application circuit 5 1.2 Block diagram . 7 2 Pin description and connection diagrams . 8 2.1 Pin descriptions . 8 2.2 Thermal data . 9 3 Electrical specifications . 10 3.1 Absolute maximum ratings 10 3.2 Electrical characteristics 10 4 Device description and operation . 12 5 Soft-start . 13 5.1 LS-less startup . 13 6 Output voltage setting and protections 15 6.1 Overcurrent . 16 6.2 Overcurrent threshold setting 17 7 Main oscillator . 18 8 High Current embedded drivers 19 8.1 Boot capacitor design 19 8.2 Power dissipation . 19 9 Application details . 21 9.1 Compensation network 21 9.2 Layout guidelines . 23 10 Application information . 25 10.1 Inductor design . 25 10.2 Output capacitor(s) 26 2/32 Doc ID 18134 Rev 2