SY8105

Applications Note:AN_SY8105 High Efficiency, 500kHz, 5A, 18V Input Synchronous Step Down Regulator General Description The SY8105 is a high efficiency 500 kHz synchronous step-down DC-DC converter capable of delivering 5.0A current. The SY8105 operates over a wide input voltage range from 4.5V to 18V and integrates main switch and synchronous switch with very low RDS(ON) to minimize the conduction loss. Low output voltage ripple and small external inductor and capacitor sizes are achieved with 500 kHz switching frequency. It adopts the instant PWM architecture to achieve fast transient responses for high step down applications Ordering Information SY8105 □(□□)□ Temperature Code Package Code Optional Spec Code Ordering Number Package type Note SY8105ADC TSOT23-6 -- Features low RDS(ON) for internal switches (top/bottom): 40mΩ/26mΩ 4.5-18V input voltage range 5.0A output current capability 500 kHz switching frequency Instant PWM architecture to achieve fast transient responses. Internal softstart limits the inrush current Cycle-by-cycle peak current limitation 1.5% 0.6V reference TSOT23-6 package Applications Set Top Box Portable TV Access Point Router DSL Modem LCD TV Typical Applications Figure 1. Schematic Diagram Efficiency (%) 100 90 80 70 60 50 40 30 20 10 0 0.001 Efficiency vs. Load Current VIN=5V,VOUT=3.3V VIN=12V,VOUT=3.3V VIN=16V,VOUT=3.3V 0.01 0.1 1 Load Current (A) 10 Figure 2. Schematic Diagram AN_SY8105 Rev. 0.9 Si...