SY8088IAAC

Application Note: SY8088I High Efficiency, 1.5MHz, 1A Synchronous Step Down Regulator Preliminary Specification ` General Description Features • • • SY8088I is a high efficiency 1.5MHz synchronous step down DC/DC regulator capable of delivering up to 1A output current. It can operate over a wide input voltage range from 2.5V to 5.5V and integrates 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) 270mΩ /160mΩ High Switching Frequency 1.5MHz Minimizes the External Components Internal Soft-start Limits the Inrush Current 100% Dropout Operation Reliable Short Circuit Protection RoHS Compliant and Halogen Free Output Auto Discharge Function Compact Package: SOT23-5 SY8088 □(□□ □□)□ □□ □ Tempera ture Code Packa ge Code Optional Spec Code Ordering Number SY8088IAAC Package type SOT23-5 Applications • • • • Note -- Set Top Box USB Dongle Media Player Smart phone Typical Applications VIN: 2.5-5.5V CIN 10µF/6.3V 4 1 LX IN 3 L1:2.2µH VOUT:1.8V RH 100k EN FB Cff 22pF COUT 10µF/6.3V 5 GND RL 49.9k 2 Figure1. Schematic Diagram AN_SY8088I Rev. 0.1 Silergy Corp. Confidential- Prepared for Customer Use Only 1 AN_SY8088I Pinout (Top View) (SOT23-5) Top Mark: bPxyz (device code: bP, x=year code, y=week code, z= lot number code) Pin Name Pin Number 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. 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: VOUT=0.6×(1+RH/RL). FB Pin Description Block Diagram IN Internal Power Current Sense Input UVLO EN LX 0.6V Control Logic FB Soft Start GND Thermal Detect Figure2. Block Diagram AN_SY8088I Rev. 0.1 Silergy Corp. Confidential- Prepared for Customer Use Only 2 AN_SY8088I Absolute Maximum Ratings (Note 1) Supply Input Voltage----------------------------------------------------------------------------------------------------------- 6.0V EN, FB Voltage----------------------------------------------------------------------------------------------------------- VIN + 0.6V LX Voltage------------------------------------------------------------------------------------------------------ -0.3V(*1) to 6.0V(*2) Power Dissipation, PD @ T A = 25°C ------------------------------------------------------------------------------- 0.77W Package Thermal Resistance (Note 2) θ JA --------------------------------------------------------------------------------------------------------------- 130°C/W θ JC ----------------------------------------------------------------------------------------------------------------- 28°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