EVB_RT7272AGSP Richtek

RT7272AGSP Evaluation Board Purpose The RT7272A is a high-efficiency current mode synchronous step-down regulator that can deliver up to 3A output current from a wide input voltage range of 4.5V to 36V. This document explains the function and use of the RT7272A evaluation board (EVB) and provides information to enable operation and modification of the evaluation board and circuit to suit individual requirements. Table of Contents Purpose .......................................................................................................................................... 1 Introduction .................................................................................................................................... 2 General Product Information ...................................................................................................... 2 Key Performance Summary Table ............................................................................................. 2 Bench Test Setup Conditions ......................................................................................................... 3 Headers Description and Placement .......................................................................................... 3 Test Points .................................................................................................................................. 3 Power-up & Measurement Procedure ........................................................................................ 4 Output Voltage Setting ............................................................................................................... 4 Schematic, Bill of Materials and Board Layout ............................................................................... 5 EVB Schematic Diagram ............................................................................................................ 5 Bill of Materials ........................................................................................................................... 6 EVB Layout ................................................................................................................................. 7 Other Technical Information ......................................................................................................... 10 UG7272AGSP-00 March 2014 www.richtek.com RT7272AGSP Evaluation Board Introduction General Product Information General Description The RT7272A is a high efficiency, current mode synchronous step-down DC/DC converter that can deliver up to 3A output current over a wide input voltage range from 4.5V to 36V. The device integrates a 150m high side and an 80m low side MOSFET to achieve high conversion efficiency up to 95%. The current mode control architecture supports fast transient response and uses a simple compensation circuit. A cycle-by-cycle current limit function provides protection against a shorted output and an internal soft-start eliminates input surge current during start-up. The RT7272A provides complete protection functions such as input under voltage lockout, output under voltage protection, over current protection and thermal shutdown. The RT7272A is available in the thermal enhanced SOP-8 (Exposed Pad) package. Features 4.5V to 36V Input Voltage Range 3A Output Current Internal N-MOSFETs Current Mode Control Fixed Frequency Operation : 500kHz Adjustable Output Voltage from 0.8V to 30V High Efficiency Up to 95% Stable with Low ESR Ceramic Output Capacitors Cycle-by-Cycle Current Limit Adjustable Current Limit Key Performance Summary Table Key features Evaluation board number: PCB001 V1 Default Input Voltage 12V Max Output Current 3A (OCP level set to 5.5A typical by R = 137k ) LIM Default Output Voltage 3.3V Default Marking & Package Type RT7272AGSP, SOP-8 (Exposed Pad) Operation Frequency Steady 500kHz at all load currents 4.5V to 36V Wide Input Voltage Range Other Key Features Adjustable Current Limit 2A to 6A Over Current Protection & Output Under-Voltage-Protection (hiccup mode) Protection Input Under-voltage Lock-out Thermal Shutdown UG7272AGSP-00 March 2014 www.richtek.com 2