SY8859QWC

SY8859 High Efficiency 1.0MHz, 3A Synchronous Step Down Regulator ` General Description Features SY8859 is a high efficient 1.0MHz synchronous step down DC/DC regulator capable of delivering up to 3A output current. The SY8859 can operate over a wide input voltage range from 2.7V 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 1.0MHz switching frequency.          Ordering Information Low RDS(ON) for Internal Switches (Top/Bottom) 85mΩ /50mΩ 2.7~5.5V Input Voltage Range 55µA Low Quiescent Current Ultra Fast Load Transient Speed High Switching Frequency 1.0MHz Minimizes the External Components Internal Soft-start Limits the Inrush Current Reliable Short Circuit Protection Output Auto Discharge Function RoHS Compliant and Halogen Free Compact Package: QFN1.5×1.5-7 SY8859 □(□□)□ Temperature Code Package Code Optional Spec Code Ordering Number SY8859QWC Package type QFN1.5×1.5-7 Applications      Note -- Smart Phone LCD TV Set Top Box Mini-Notebook PC Access Point Router Typical Applications Efficiency vs. Output Current 95 SY8859 CIN 22µF/6.3V RPG: 100k 5 3 L:1.0µH LX IN 6 RH: 100k PG FB 2 1 EN 4 MODE GND RL : 49.9k 7 91 VOUT:1.8V Cff: 47pF COUT 22µF/6.3V Efficiency (%) VIN : 2.7V~5.5V 87 83 VIN=3.3V,VOUT=1.8V VIN=4.2V,VOUT=1.8V VIN=5.0V,VOUT=1.8V 79 75 0.01 0.10 10.00 1.00 Output Current (A) Figure1. Schematic Diagram SY8859 Rev. 0.9B © 2018 Silergy Corp. Figure2. Efficiency vs. Output Current Silergy Corp. Confidential- Prepared for Customer Use Only 1 All Rights Reserved. SY8859 Pinout (Top View) FB 1 7 GND EN 2 6 LX 3 4 PG 5 MODE IN (QFN1.5×1.5-7) Top Mark: Prxyz (device code: Pr, x=year code, y=week code, z= lot number code) Pin Name Pin Number FB 1 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=0.6V×(1+RH/RL) EN 2 Enable control. Pull high to turn on. Do not leave it floating. PG 3 MODE 4 IN 5 Input pin. Decouple this pin to GND pin with at least a 22µF ceramic capacitor. LX 6 Inductor pin. Connect this pin to the switching node of the inductor. GND 7 Ground pin. SY8859 Rev. 0.9B © 2018 Silergy Corp. Pin Description Power good indicator (Open drain output). Low if the output < 90% of regulation voltage or the output >120% of regulation voltage. High otherwise. Connect a pull-up resistor to the input pin. Mode control pin. Do not leave it floating. MODE=high, selected Force CCM mode operation during light load. MODE=low, selected PFM mode operation during light load. Silergy Corp. Confidential- Prepared for Customer Use Only 2 All Rights Reserved. SY8859 Block Diagram IN Internal Power Input UVLO Current Sensor EN LX MODE Control Logic - FB Current Sensor + 0.6V GND Soft Start PG Thermal Sensor Figure3. Block Diagram Absolute Maximum Ratings (Note 1) Supply Input Voltage --------------------------------------------------------------- -------------------------------------- 6.0V EN, PG, MODE, FB Voltage ---------------------------------------------------------------------------------------- VIN + 0.6V （ ） （ ） LX Voltage -------------------------------------------------------------------------------------------------- -0.3V *1 to 6V *2 Power Dissipation, PD @ TA = 25°C, QFN1.5×1.5-7 -------------------------------------------------------------------------------------------------------- 1.5W Package Thermal Resistance (Note 2) θ JA ---------------------------------------------------------------------------------------------------------------- 66°C/W θ JC ----------------------------------------------------------------------------------------------------------------- 5°C/W Junction Temperature Range ------------------------------------------------------------------------------ -40°C 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