L6731DTR STMicroelectronics

L6731D Adjustable step-down controller with synchronous rectification dedicated to DDR memory Features Input voltage range from 1.8 V to 14 V Supply voltage range from 4.5 V to 14 V Adjustable output voltage down to 0.6 V with 0.8 % Accuracy over line voltage and temperature (0 C~125 C) Fixed frequency voltage mode control T lower than 100 ns ON 0 % to 100 % duty cycle HTSSOP16 (exposed pad) V input sense DDR Regulates V and V within 1 % of V TT TTREF DDQ Soft-start and inhibit Applications High current embedded drivers Predictive anti-cross conduction control High performance / high density DC-DC modules Programmable high-side and low-side R DS(on) sense over-current-protection Low voltage distributed DC-DC Selectable switching frequency 250 kHz / niPoL converters 500 kHz DDR memory supply Power good output DDR termination supply Sink/source capability for DDR memory and Graphic cards termination supply Over-voltage protection Thermal shutdown Package: HTSSOP16 Table 1. Device summary Order codes Package Packaging L6731D HTSSOP16 Tube L6731DTR HTSSOP16 Tape and reel June 2008 Rev 3 1/23 www.st.com 23Contents L6731D Contents 1 Summary description 3 1.1 Functional description 4 2 Electrical data 5 2.1 Maximum rating . 5 2.2 Thermal data . 5 3 Pin connections and functions 6 4 Electrical characteristics . 8 5 Device description . 10 5.1 Oscillator . 10 5.2 Internal LDO . 10 5.3 Bypassing the LDO to avoid the voltage drop with low Vcc . 11 5.4 Internal and external references 11 5.5 Error amplifier 12 5.6 Soft-start 12 5.7 Driver section 13 5.8 Monitoring and protections 13 5.9 HICCUP mode during an OCP . 15 5.10 Thermal shutdown 15 5.11 Minimum on-time (TON, MIN) . 15 6 Application details . 17 6.1 Inductor design . 17 6.2 Output capacitors . 17 6.3 Input capacitors 18 6.4 Compensation network 18 7 Package mechanical data 21 8 Revision history . 22 2/23