G5312 Global Mixed-mode Technology High Efficiency 8A Synchronous Buck Converter Features General Description G5312 is a 8A, synchronous DC/DC buck converter with integrated 20mΩ N-channel high-side MOSFET and 20mΩ N-channel low-side MOSFET. It 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 G5312 achieves high efficiency at a reduced cost by eliminating the current-sense resistor found in traditional current-mode PWMs. Single-stage buck conversion allows these devices to directly step down high-voltage batteries for the highest possible efficiency. The built-in 5V LDO supports 20mA for internal circuits. The G5312 is intended for the main power supply of LCD TV, Notebook Computer, or other low-voltage supplies as low as 0.75V. The G5312 is available in QFN4X4-28 package. Ultra-High Efficiency Integrated 20mΩ at Vcc=5V N-Channel MOSFET for Low Side Integrated 20mΩ at Vcc=5V N-Channel MOSFET for High Side No Current-Sense Resistor (Lossless ILIMIT) Quasi-PWM with 100ns Load-Step Response 1% VOUT Accuracy Over Line and Load Programmable Switching Frequency Adjustable Output Range from 0.75V 4.5V to 28V Adapter or Battery Input Range Integrated Boost Switch OVP & UVP Over Temperature Protection (non-latch) 3.3ms Soft-Start Power-Good Indicator Fixed 5V, 20mA Linear Regulator Applications LCD Monitor/LCD TV Notebook Computers I/O Supply Chipset/RAM Supply as Low as 0.75V Networking Power Supply Ordering Information ORDER NUMBER MARKING TEMP. RANGE PACKAGE (Green) G5312QN1U 5312 -40°C to +85°C QFN4X4-28 G5312QN2U 5312 -40°C to +85°C QFN4X4-28 Note:QN: QFN4X4-28 1 & 2: Leadframe Code U : Tape & Reel TON EN BST NC 23 22 21 25 24 VCC OUT 26 PGOOD 21 FB 22 28 BST NC 23 27 TON EN 24 VCC OUT 25 FB 27 26 PGOOD 28 Pin Configuration ILIM 1 20 V+ ILIM 1 20 V+ AGND 2 19 V+ AGND 2 19 V+ V5V 3 18 V+ V5V 3 18 V+ PGND 4 17 V+ PGND 4 17 V+ LX 5 16 PGND 15 16 PGND PGND 15 PGND 12 PGND 13 11 PGND 14 10 LX PGND 9 LX PGND 8 14 LX 13 8 PGND LX LX PGND 7 12 6 LX LX PGND LX 7 11 6 LX PGND LX 9 5 10 LX V+ AGND LX V+ LX AGND G5312QN2U QFN4X4-28 G5312QN1U QFN4X4-28 Note: Recommend connecting the Thermal Pad to the Ground for excellent power dissipation. TEL: 886-3-5788833 http://www.gmt.com.tw Ver: 1.1 Oct 21, 2013 1