Application Note: SY8089A1

1 Application Note: SY8089A1 . High Efficiency, , 2A. synchronous step down Regulator Advanced Design Specification `. General Description Features SY8089A1 is a high efficiency synchronous to Input Voltage Range step down DC/DC regulator capable of delivering up to 50 A Low Quiescent Current 2A output current. It can operate over a wide input Low RDS(ON) for Internal Switches (Top/Bottom). voltage range from to and integrate main 130m /85m . switch and synchronous switch with very low RDS(ON) High Switching Frequency Minimizes to minimize the conduction loss. the External Components The low output voltage ripple, the small external Internal Soft-start Limits the Inrush Current inductor and the capacitor sizes are achieved with 100% Dropout Operation switching frequency.

2 Hic-cup for Short Circuit Protection Output Auto Discharge Function RoHS Compliant and Halogen Free Ordering Information Compact Package: SOT23-5. SY8089 ( ) . Temperature Code Package Code Applications Optional Spec Code Set Top Box Ordering Number Package type Note USB Dongle SY8089A1 AAC SOT23-5 -- Media Player Smart Phone Typical Applications Efficiency vs. Output Current L1 H. VIN: IN LX 100. CIN RH Cff COUT. 10 100k 22pF 10 F/10V 95. EN FB. RL. Efficiency (%). GND 90. 85. Figure1. Schematic Diagram 80. Inductor and COUT Selection Table COUT [ F] VIN= , VOUT= VOUT [V] L [ H] 75. 10 22 2 22 VIN= , VOUT= VIN= , VOUT=.

3 70. 1 10. Output Current (A). Note: ' means recommended for most applications. Figure2. Efficiency vs. Output Current AN_SY8089A1 Rev. Silergy Corp. Confidential- Prepared for Customer Use Only 1. 2018 Silergy Corp. All Rights Reserved. AN_SY8089A1. Pinout (Top View). EN 1 5 FB. GND 2. LX 3 4 IN. (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 10 F ceramic capacitor.

4 Output feedback pin. Connect this pin to the center point of the output resistor divider FB 5. (as shown in Figure 1) to program the output voltage: V OUT= (1+RH/RL). Block Diagram IN. Current Internal Input Sense Power UVLO. EN LX. Control Logic GND. FB. Soft Thermal Start Detect Figure3. Block Diagram AN_SY8089A1 Rev. Silergy Corp. Confidential- Prepared for Customer Use Only 2. 2018 Silergy Corp. All Rights Reserved. AN_SY8089A1. Absolute Maximum Ratings (Note 1). Supply Input Voltage ---------------------------------------- ---------------------------------------- -------------- to FB, EN Voltage--------------------------------- ---------------------------------------- ------------------ to VIN+ LX Voltage--------------------------------- ---------------------------------------- ------------------------------ (*1) to (*2).

5 Power Dissipation, P D @ T A = 25 C Package Thermal Resistance (Note 2). 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.

6 (*1). LX Voltage Tested down to -3V<40ns (*2). LX Voltage Tested Up to +7V<40ns Recommended Operating Conditions (Note 3). Supply Input Voltage ---------------------------------------- ---------------------------------------- ----------------- to Junction Temperature Range ---------------------------------------- ---------------------------------------- ----- -40 C to 125 C. Ambient Temperature Range ---------------------------------------- ---------------------------------------- ------- -40 C to 85 C. AN_SY8089A1 Rev. Silergy Corp. Confidential- Prepared for Customer Use Only 3. 2018 Silergy Corp. All Rights Reserved.

7 AN_SY8089A1. Electrical Characteristics (VIN = 5V, VOUT = , L = H, COUT = 10 F, TA = 25 C, unless otherwise specified). Parameter Symbol Test Conditions Min Typ Max Unit Input Voltage Range VIN V. Input UVLO Threshold VUVLO V. Input UVLO Hysteresis VHYS 150 mV. Quiescent Current IQ VFB=VREF 105% 50 70 A. Shutdown Current ISHDN VEN=0V 1 A. Feedback Reference Voltage VREF IOUT= , CCM 591 600 609 mV. LX Node Discharge Resistance RDIS 50 . Top FET RON RDS(ON)1 130 m . Bottom FET RON RDS(ON)2 85 m . EN Input Voltage High VEN,H V. EN Input Voltage Low VEN,L V. Min On Time tON,MIN 60 ns Maximum Duty Cycle DMAX 100 %.

8 Turn On Delay tON,DLY from EN high to LX start switching 350 s Soft-start Time tSS 1 ms Switching Frequency fSW IOUT= , CCM MHz Top FET Current Limit ILMT,TOP A. Thermal Shutdown Temperature TSD 150 C. Thermal Shutdown Hysteresis THYS 20 C. Note 1: Stresses beyond the Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only. Functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.

9 Note 2: JA of SY8089A1 is measured in the natural convection at T A = 25oC on a 2OZ two-layer Silergy evaluation board. Pin 3 is the case position for JC measurement. Note 3: The device is not guaranteed to function outside its operating conditions. AN_SY8089A1 Rev. Silergy Corp. Confidential- Prepared for Customer Use Only 4. 2018 Silergy Corp. All Rights Reserved. AN_SY8089A1. Typical Performance Characteristics Efficiency vs. Output Current Efficiency vs. Output Current 95 100. 95. 90. Efficiency (%). Efficiency (%). 90. 85. 85. 80. 80. 75 VIN= ,VOUT= 75 VIN= , VOUT= VIN= , VOUT= VIN= , VOUT= VIN= , VOUT= VIN= , VOUT= 70 70.

10 1 10 1 10. Output Current (A) Output Current (A). Output Ripple Efficiency vs. Output Current (VIN= , VOUT= , IOUT=2A). 100. 95 Vout 50mV/div Efficiency (%). 90. VLX 85. 80 IL 2A/div VIN= , VOUT= VIN= , VOUT= 75. 1 10. Time (1 s/div). Output Current (A). Startup from Enable Shutdown from Enable (VIN= , VOUT= , RLOAD= ) (VIN= , VOUT= , RLOAD= ). VEN 2V/div VEN 2V/div VOUT 1V/div VOUT 1V/div VLX 2V/div VLX 2V/div IL 2A/div IL 2A/div Time (400 s/div) Time (400 s/div). AN_SY8089A1 Rev. Silergy Corp. Confidential- Prepared for Customer Use Only 5. 2018 Silergy Corp. All Rights Reserved. AN_SY8089A1. Load Transient Load Transient (VIN= , VOUT= ,IOUT=0~1A) (VIN= , VOUT= ,IOUT= ~2A).