G5603 Global Mixed-mode Technology Inc. High-Speed Step-Down Controller Features General Description G5603 uses constant on-time control scheme to handle wide input/output voltage ratios with ease and provides 100ns “instant-on” response to load transients while maintaining a relatively constant switching frequency. The G5603 achieves high efficiency at a reduced cost by eliminating the current-sense resistor found in traditional current-mode PWMs. Efficiency is further enhanced by an ability to drive very large synchronous rectifier MOSFETs. Single-stage buck conversion allows these devices to directly step down high-voltage batteries for the highest possible efficiency. Alternatively, two-stage conversion (stepping down the +5V system supply instead of the battery) at a higher switching frequency allows the minimum possible physical size. The G5603 is intended for CPU core, chipset, DRAM, or other low-voltage supplies as low as 0.75V. The G5603 is available in TSSOP-14 、 TQFN3X3-16 and TQFN3.5X3.5-14 package and includes over voltage protection. Ultra-High Efficiency No Current-Sense Resistor (Lossless ILIMIT) Quasi-PWM with 100ns Load-Step Response 1% VOUT Accuracy Over Line and Load 0.75V to 3.6V Adjustable Output Range 4.5V to 24V Battery Input Range Integrated Boost Diode OVP & UVP 1.7ms Soft-Start Drives Large Synchronous-Rectifier FETs Power-Good Indicator Applications Notebook Computers CPU Core Supply I/O Supply Chipset/RAM Supply as Low as 0.75V Networking Power Supply Ordering Information TEMP. RANGE PACKAGE (Green) ORDER NUMBER MARKING G5603D21U G5603 -40°C to +85°C TSSOP-14 G5603R41U G5603RU1U 5603 5603 -40°C to +85°C -40°C to +85°C TQFN3X3-16 TQFN3.5x3.5-14 Note: D2: TSSOP-14 RU: TQFN3.5x3.5-14 1: Bonding Code U : Tape & Reel R4: TQFN3X3-16 VDD PGOOD 4 PGOOD 6 9 DL AGND 7 8 PGND TSSOP-14 9 VDD 5 6 7 8 NC AGND PGND DL EN_SKIP G5603 TQFN3X3-16 DL VDD 10 9 5 ILIM 1 6 FB 10 8 PGND 7 AGND Thermal Pad PGOOD 3 ILIM FB 10 ILIM 14 5 11 BST 11 LX Thermal Pad FB 4 LX VCC 11 2 4 VCC DH VCC LX DH 12 13 3 12 OUT 12 2 1 3 OUT TON DH OUT 13 BST 2 13 TON NC BST 14 14 EN_SKIP 1 15 EN_SKIP TON G5603 16 Pin Configuration G5603 TQFN3.5X3.5-14 Note: Recommend connecting the Thermal Pad to the Ground for excellent power dissipation. TEL: 886-3-5788833 http://www.gmt.com.tw Ver: 0.92 Mar 25, 2011 1