SY8089A1AAC

Application Note: SY8089A1 High Efficiency, 1.5MHz, 2A Synchronous Step Down Regulator Advanced Design Specification ` General Description Features SY8089A1 is a high efficiency 1.5MHz synchronous step down DC/DC regulator capable of delivering up to 2A output current. It can operate over a wide input voltage range from 2.5V to 5.5V and integrate main switch and synchronous switch with very low RDS(ON) to minimize the conduction loss. The low output voltage ripple, the small external inductor and the capacitor sizes are achieved with 1.5MHz switching frequency. Ordering Information           2.5V to 5.5V Input Voltage Range 50μA Low Quiescent Current Low RDS(ON) for Internal Switches (Top/Bottom) 130mΩ /85mΩ High Switching Frequency 1.5MHz Minimizes the External Components Internal Soft-start Limits the Inrush Current 100% Dropout Operation Hic-cup for Short Circuit Protection Output Auto Discharge Function RoHS Compliant and Halogen Free Compact Package: SOT23-5 SY8089 □(□□)□ Temperature Code Package Code Optional Spec Code Ordering Number SY8089A1AAC Package type SOT23-5 Applications Note --     Set Top Box USB Dongle Media Player Smart Phone Typical Applications Efficiency vs. Output Current L1:1.0µH VOUT:1.8V LX IN CIN 10μF/6.3V Cff 22pF RH 100k COUT 10μF/10V RL 49.9k GND Figure1. Schematic Diagram Inductor and COUT Selection Table 1.2/ 1.8 /3.3 95 FB EN VOUT [V] 100 Efficiency (%) VIN: 2.5-5.5V L [µH] 4.7 COUT [µF] 10 22 2×22 0.47 √ √ √ 1.0 ☆ √ √ √ √ 2.2 90 85 80 VIN=3.3V, VOUT=1.8V VIN=4.2V, VOUT=1.8V VIN=5.0V, VOUT=1.8V 75 70 0.001 0.01 0.1 1 10 Output Current (A) Note: ‘☆’ means recommended for most applications. Figure2. Efficiency vs. Output Current AN_SY8089A1 Rev. 0.0 © 2018 Silergy Corp. Silergy Corp. Confidential- Prepared for Customer Use Only 1 All Rights Reserved. AN_SY8089A1 Pinout (Top View) EN 1 5 FB 4 IN GND 2 LX 3 (SOT23-5) Top Mark: qHxyz (device code: qH, x=year code, y=week code, z= lot number code) Pin Name Pin Number Pin Description EN 1 Enable control. Pull high to turn on. Do not leave it floating. GND 2 Ground pin. LX 3 Inductor pin. Connect this pin to the switching node of the inductor. IN 4 Input pin. Decouple this pin to the GND pin with at least a 10µF ceramic capacitor. FB 5 Output feedback pin. Connect this pin to the center point of the output resistor divider (as shown in Figure 1) to program the output voltage: V OUT=0.6×(1+RH/RL). Block Diagram IN Internal Power Current Sense Input UVLO LX EN 1.2V Control Logic 0.6V GND FB Soft Start Thermal Detect Figure3. Block Diagram AN_SY8089A1 Rev. 0.0 © 2018 Silergy Corp. Silergy Corp. Confidential- Prepared for Customer Use Only 2 All Rights Reserved. AN_SY8089A1 Absolute Maximum Ratings (Note 1) Supply Input Voltage ---------------------------------------------------------------------------------------------- -0.3V to 6.0V FB, EN Voltage------------------------------------------------------------------------------------------- -0.3V to VIN+0.6V LX Voltage------------------------------------------------------------------------------------------------------- -0.3V(*1) to 6.0V(*2) Power Dissipation, P D @ T A = 25°C -------------------------------------------------------------------------------0.83W Package Thermal Resistance (Note 2) θ θ JA ------------------------------------------------------------------------ ------------------------------120°C/W JC ----------------------------------------------------------------------------------------------- --------------20° C/W Junction Temperature Range ------------------------------------------------------------------------------------- -40oC to 150°C Lead Temperature (Soldering, 10 sec.) ------------------------------------------------------------------------------------ 260°C Storage Temperature Range -------------------------------------------------------------------------------------- -65°C to 150°C (*1) LX Voltage Tested Down to -3V