SM8081AAC

Application Note: SM8081 High Efficiency, 1.5MHz, 1A Synchronous Step Down Regulator ` General Description Features    SM8081 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 70μA Low Quiescent Current Low RDS(ON) for Internal Switches (Top/Bottom) 260mΩ /170mΩ High Switching Frequency 1.5MHz Minimizes the External Components Internal Soft-start Limits the Inrush Current 100% Dropout Operation Reliable Short Circuit Protection Output Auto Discharge Function RoHS Compliant and Halogen Free Compact Package: SOT23-5 SM8081 □(□□)□ Temperature Code Package Code Optional Spec Code Ordering Number SM8081AAC Package type SOT23-5 Applications     Note -- Set Top Box USB Dongle Media Player Smart phone Typical Applications Efficiency vs. Output Current 100 CIN 10μF/6.3V 4 LX IN 3 L1:2.2µH RH 100k 1 EN FB GND 95 VOUT:1.8V 5 RL 49.9k Cff 22pF COUT 10μF/6.3V Efficiency (%) VIN: 2.5-5.5V 90 85 80 VIN=3.3V,VOUT=1.8V 2 VIN=4.2V,VOUT=1.8V 75 VIN=5.0V,VOUT=1.8V 70 0.001 0.01 0.1 1 Output Current (A) AN_SM8081 Rev. 0.9 © 2019 Silergy Corp. Silergy Corp. Confidential- Prepared for Customer Use Only 1 All Rights Reserved. SM8081 Pinout (Top View) EN 1 5 FB GND 2 4 LX 3 IN (SOT23-5) Top Mark: J9xyz (device code: J9 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 EN LX 0.6V Control Logic FB Soft Start GND Thermal Detect Figure2. Block Diagram AN_SM8081 Rev. 0.9 © 2019 Silergy Corp. Silergy Corp. Confidential- Prepared for Customer Use Only 2 All Rights Reserved. SM8081 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, P D @ 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