SY7152AABC

Applications Note: SY7152A High Efficiency 1MHz, 2A Step Up Regulator Preliminary Specification General Description Features The SY7152A is a high efficiency, current-mode control Boost regulator. The device integrates a 130mΩ low RDS(ON) N-channel MOSFET for high efficiency. The fixed 1MHz switching frequency and internal compensation reduce external components size and count. The build-in internal soft start circuitry minimizes the inrush current at start-up. The SY7152A is available in compact SOT23-6 package. • • • • • • • • Ordering Information Applications SY7152 □(□□)□ • WLED Drivers • Networking cards powered from PCI or PCIexpress slots l er na nt rI ar ed fo Package type SOT23-6 Note 2A Sil er gy Co rp .C on fid en Typical Applications tia l-P re p Temperature Code Package Code Optional Spec Code Temperature Range: -40°C to 85°C Ordering Number SY7152AABC Wide input range: 3-8V bias input, 16Vout max 1MHz switching frequency Minimum on time: 100ns typical Minimum off time: 100ns typical Low RDS(ON): 130mΩ RoHS Compliant and Halogen Free Accurate Reference: 0.6VREF Compact package: SOT23-6 Figure 1. Schematic Diagram AN_SY7152A Rev.0.1 Figure 2. Efficiency vs Load Current Silergy Corp. Confidential- Prepared for Customer Use Only 1 SY7152A l Pinout (top view) er na （SOT23-6） Top Mark: UBxyz (Device code: UB, x=year code, y=week code, z= lot number code) nt 4 6 rI EN NC Pin Description Input pin. Decouple this pin to GND pin with 1uF ceramic cap. Ground pin Inductor node. Connect an inductor between IN pin and LX pin. Feedback pin. Connect a resistor R1 between VOUT and FB, and a resistor R2 between FB and GND to program the output voltage: VOUT=0.6V*(R1/R2+1). Enable control. High to turn on the part. Don’t leave it floated. No connection. fo Pin Number 5 2 1 3 tia l-P re p ar ed Pin Name IN GND LX FB Absolute Maximum Ratings (Note 1) .C on fid en LX, IN, EN ----------------------------------------------------------------------------------------------------------------------- 18V All other pins-------------------------- ------------------------------------------------------------------------------------------ 3.6V Power Dissipation, PD @ TA = 25°C SOT23-6 ----------------------------------------------------------------------------- 0.6W Package Thermal Resistance (Note 2) θ JA --------------------------------------------------------------------------------------------------------------- 161°C/W θ JC --------------------------------------------------------------------------------------------------------------- 130°C/W Junction Temperature Range ----------------------------------------------------------------------------------------------- 125°C Lead Temperature (Soldering, 10 sec.) ----------------------------------------------------------------------------------- 260°C Storage Temperature Range ------------------------------------------------------------------------------------- -65°C to 150°C Co rp Recommended Operating Conditions (Note 3) Sil er gy Input Voltage Supply------------------------------------------------------------------------------------------------------ 3V to 8V Junction Temperature Range ------------------------------------------------------------------------------------- -40°C to 125°C Ambient Temperature Range ------------------------------------------------------------------------------------- -40°C to 85°C AN_SY7152A Rev.0.1 Silergy Corp. Confidential- Prepared for Customer Use Only 2 SY7152A Electrical Characteristics (VIN = 5V, VOUT=12V, IOUT=100mA, TA = 25°C unless otherwise specified) Symbol VIN IQ ISHDN Rds(on) Test Conditions Min 3 Typ VFB=0.66V EN=0 Max 8 100 15 130 2 Fsw VREF 0.8 0.588 er na l ILIM1 MHz V 1.8 nA V rI 50 fo VIN,UVLO tia l-P re p ar ed UVLO,HYS TSD VENH VENL IEN A 1.2 0.612 nt 1 0.6 Unit V µA µA mΩ 0.1 150 V °C 15 °C 1.5 0.4 100 0 90 V V nA % en Parameter Input Voltage Range Quiescent Current Shutdown Current Low Side Main FET RON Main FET Current Limit Switching Frequency Feedback Reference Voltage FB pin input current IN UVLO Rising Threshold UVLO Hysteresis Thermal Shutdown Temperature Thermal Shutdown Recovery Hysteresis EN Rising Threshold EN Falling Threshold EN Pin Input Current Max Duty Cycle .C on fid Note 1: Stresses listed beyond the “Absolute Maximum Ratings” may cause permanent damage to the device. These are for stress ratings. Functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions may remain possibility to affect device reliability. Co rp Note 2: θ JA is measured in the natural convection at TA = 25°C on a low effective single layer thermal conductivity test board of JEDEC 51-3 thermal measurement standard. Test condition: Device mounted on 2” x 2” FR-4 substrate PCB, 2oz copper, with minimum recommended pad on top layer and thermal vias to bottom layer ground plane. Sil er gy Note 3: The device is not guaranteed to function outside its operating conditions. AN_SY7152A Rev.0.1 Silergy Corp. Confidential- Prepared for Customer Use Only 3 SY7152A fo rI nt er na l Efficiency (%) Efficiency (%) Typical Performance Characteristics Load Transient IO 0.5A/div tia l-P re p 500mV/div Sil er gy Co rp .C on Time (100µs/div) fid en VOUT(AC) ar ed (VIN=3.3V, VOUT=5V, IO=0.1~ 1A) Shutdown from VIN (VIN=3.3V, VOUT=5V, IO=1A) VIN 2V/div VO 5V/div IO 1A/div Time (2ms/div) AN_SY7152A Rev. 0.1 Silergy Corp. Confidential- Prepared for Internal Use Only 4 SY7152A VIN Startup from VIN Shutdown from VIN (VIN=5V, VOUT=12V, IO=600mA) (VIN=5V, VOUT=12V, IO=600mA) VIN 5V/div VO 10V/div IO 0.5A/div 5V/div VO 10V/div 0.5A/div er na l IO Time (2ms/div) Startup from Enable Shutdown from Enable ar ed fo rI nt Time (2ms/div) (VIN=3.3V, VOUT=5V, IO=1A) (VIN=3.3V, VOUT=5V, IO=1A) EN 5V/div tia l-P re p EN VO VO 2V/div IO 0.5A/div 2V/div 0.5A/div Time (40µs/div) .C on Time (2ms/div) fid en IO 5V/div Shutdown from Enable (VIN=5V, VOUT=12V, IO=600mA) Co rp Startup from Enable (VIN=5V, VOUT=12V, IO=600mA) 5V/div VO 10V/div er gy EN 5V/div VO 10V/div IO 0.5A/div 0.5A/div Sil IO EN Time (2ms/div) AN_SY7152A Rev. 0.1 Time (200µs/div) Silergy Corp. Confidential- Prepared for Internal Use Only 5 SY7152A Output Ripple Output Ripple (VIN=3.3V,VOUT=5V, IO=100mA) (VIN=3.3V,VOUT=5V, IO=1A) VOUT(AC) 20mV/div VOUT(AC) 50mV/div 2V/div VLX 2V/div IL 0.5A/div IL 1A/div er na l VLX Time (1µs/div) rI nt Time (1µs/div) Output Ripple 20mV/div 5V/div 0.5A/div en IL tia l-P re p VLX ar ed VOUT(AC) fo (VIN=5V,VOUT=12V, IO=60mA) Sil er gy Co rp .C on fid Time (1µs/div) AN_SY7152A Rev. 0.1 Silergy Corp. Confidential- Prepared for Internal Use Only 6 SY7152A R2 = (R1 × 0.6V)/(VOUT − 0.6V) VOUT R1 fid en Input capacitor CIN: The ripple current through input capacitor is calculated as: VIN ⋅ (VOUT − VIN) 2 3 ⋅ L ⋅ FSW ⋅ VOUT l er na nt The SY7152A regulator IC is quite tolerant of different ripple current amplitude. Consequently, the final choice of inductance can be slightly off the calculation value without significantly impacting the performance. 2) The saturation current rating of the inductor must be selected to be greater than the peak inductor current under full load conditions. VIN(VOUT − VIN)  VOUT  ISAT,MIN >   × IOUT_MAX + 2 × FSW × L × VOUT  VIN  R2 GND ICIN_RMS = where FSW is the switching frequency and IOUT,MAX is the maximum load current. tia l-P re p 0.6VFB 2 rI Feedback resistor dividers R1 and R2: Choose R1 and R2 to program the proper output voltage. To minimize the power consumption under light loads, it is desirable to choose large resistance values for both R1 and R2. A value of between 10k and 1M is recommended for both resistors. If R1=200k is chosen, then R2 can be calculated to be: (VOUT − VIN)  VIN  L=  V OUT F SW × IOUT, MAX × 40%   fo Because of the high integration in the SY7152A IC, the application circuit based on this regulator IC is rather simple. Only input capacitor CIN, output capacitor COUT, inductor L, diode D and feedback resistors (R1 and R2) need to be selected for the targeted applications specifications. 1) Choose the inductance to provide the desired ripple current. It is suggested to choose the ripple current to be about 40% of the maximum average input current. The inductance is calculated as: ar ed Applications Information Co rp .C on To minimize the potential noise problem, place a typical X5R or better grade ceramic capacitor really close to the IN and GND pins. Care should be taken to minimize the loop area formed by CIN, and IN/GND pins.In this case a 10uF low ESR ceramic is recommended. Sil er gy Output capacitor COUT: The output capacitor is selected to handle the output ripple noise requirements. Both steady state ripple and transient requirements must be taken into consideration when selecting this capacitor. For the best performance, it is recommended to use X5R or better grade ceramic capacitor with 10uF/25V. Boost inductor L: There are several considerations in choosing this inductor. 3) The DCR of the inductor and the core loss at the switching frequency must be low enough to achieve the desired efficiency requirement. It is desirable to choose an inductor with DCR