SY8009BABC

Applications Note: AN_SY8009 High Efficiency 1.5MHz/1MHz, 1.5A/2A Synchronous Step Down Regulator Preliminary Spec General Description Features The SY8009A and SY8009B are high-efficiency, high frequency synchronous step-down DC-DC regulator ICs capable of delivering up to 1.5A/2A output currents. The SY8009 family operate over a wide input voltage range from 3V to 5.5V and integrate main switch and synchronous switch with very low RDS(ON) to minimize the conduction loss. • Low RDS(ON) for internal switches (top/bottom) • SY8009A: 180mΩ/120mΩ, 1.5A, SOT23-5 • SY8009B:100mΩ/80mΩ,2.0A SOT23-6, SSOT23-6 • 3-5.5V input voltage range • High switching frequency minimizes the external components • SY8009A: 1.5MHz • SY8009B: 1MHz • Internal softstart limits the inrush current • 100% dropout operation • RoHS Compliant and Halogen Free • Compact package: SOT23-5, SOT23-6 and Super SOT23-6 are pin-compatible. Other packages are available upon requests Low output voltage ripple and small external inductor and capacitor sizes are achieved with greater than 1MHz switching frequency. Ordering Information SY8009□(□□)□ Temperature Code Package Code Optional Spec Code Applications • • • • • Temperature Range: -40°C to 85°C Ordering Number SY8009AAAC SY8009BABC SY8009BEBC Note① 1.5A 2A 2A Package type SOT23-5 SOT23-6 SSOT23-6 LCD TV Set Top Box Net PC Mini-Notebook PC Access Point Router Typical Applications 96 VOUT=1.8V 94 ON/ OFF L VIN VOUT LX IN R1 CIN GND C1(opt.) COUT FB R2 Efficiency (%) 92 EN 90 88 86 82 80 Figure 1.Schematic diagram AN_SY8009 Rev. 0.71 VIN=3.3V VIN=4.2V VIN=5.5V 84 0 0.4 0.8 1.2 1.6 2 Load Current (A) Figure 2. Efficiency vs Load Current Silergy Corp. Confidential- Prepared for Internal Use Only 1 AN_SY8009 Pinout (top view) EN 1 6 FB GND 2 5 NC LX 3 SOT23-5(SY8009A) Pin Name EN GND LX IN FB SOT23-6(SY8009B) 4 IN SSOT23-6(SY8009B) Part Number Package type Top Mark① SY8009AAAC SOT23-5 ADxyz SY8009BABC SOT23-6 CUxyz SY8009BEBC SSOT23-6 ASxyz Note① ： x=year code, y=week code, z= lot number code. Pin Number Pin Description 1 Enable control. Pull high to turn on. Do not float. 2 Ground pin 3 Inductor pin. Connect this pin to the switching node of inductor. 4 Input pin. Decouple this pin to GND pin with at least 1uF ceramic cap. 6 Output Feedback Pin. Connect this pin to the center point of the output （SY8009B） resistor divider (as shown in Figure 1) to program the output voltage: VOUT=0.6*(1+R1/R2). Absolute Maximum Ratings (Note 1) Supply Input Voltage ------------------------------------------------------------------------------------------ 6.0V Enable, FB Voltage--------------------------------------------------------------------------------------------- VIN + 0.6V Power Dissipation, PD @ TA = 25°C, SOT23-5, SOT23-6 ---------------------------------------------------------------------------------- 0.55W SSOT23-6 --------------------------------------------------------------------------------------------- 0.6W Package Thermal Resistance (Note 2) SOT23-5, SOT23-6, SSOT23-6, θ JA -------------------------------------------------------------- 250°C/W SOT23-5, SOT23-6, SSOT23-6, θ JC ---------------------------------------------------------------130°C/W Junction Temperature Range ----------------------------------------- -----------------------------------------150°C Lead Temperature (Soldering, 10 sec.) ---------------------------------------------------------------------- 260°C Storage Temperature Range ---------------------------------------------------------------------------------- -65°C to 150°C ESD Susceptibility (Note 2) HBM (Human Body Mode) ----------------------------------------------------------------------------------- 2kV MM (Machine Mode) ------------------------------------------------------------------------------------------ 200V Dynamic LX voltage in 50ns duration --------------------------------------------------------------------- IN+3V to GND-4V Recommended Operating Conditions (Note 3) Supply Input Voltage ------------------------------------------------------------------------------------------3V to 5.5V Junction Temperature Range -------------------------------------------------------------------------------- -40°C to 125°C Ambient Temperature Range -------------------------------------------------------------------------------- -40°C to 85°C AN_SY8009 Rev. 0.71 Silergy Corp. Confidential- Prepared for Internal Use Only 2 AN_SY8009 Electrical Characteristics (VIN = 5V, VOUT = 2.5V, L = 2.2uH, COUT = 10uF, TA = 25°C, unless otherwise specified) Parameter Input Voltage Range Quiescent Current Shutdown Current Feedback Reference Voltage FB Input Current PFET RON Symbol VIN IQ ISHDN VREF NFET RON RDS(ON),N PFET Current Limit ILIM EN Rising Threshold EN Falling Threshold Input UVLO Threshold UVLO Hysteresis Oscillator Frequency VENH VENL VUVLO VHYS FOSC Min ON Time Max Duty Cycle Thermal Shutdown Temperature IFB RDS(ON),P Test Conditions IOUT=0, VFB=VREF ⋅ 105% EN=0 Min 3 0.588 VFB=VIN SY8009A SY8009B SY8009A SY8009B SY8009A SY8009B Typ 80 0.1 0.6 -50 Max 5.5 1 0.612 50 180 100 120 80 1.8 2.5 1.5 0.4 2.7 0.1 1.5 1 50 IOUT=200mA, SY8009A IOUT=500mA, SY8009B 100 160 TSD Unit V µA µA V nA mΩ mΩ mΩ mΩ A A V V V V MHz MHz ns % °C Note 1: Stresses listed as the above “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 for extended periods may remain possibility to affect device reliability. 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. Pin 2 of SOT23-5/SOT23-6/SSOT23-5 packages is the case position for θ JC measurement. Note 3: The device is not guaranteed to function outside its operating conditions. AN_SY8009 Rev. 0.71 Silergy Corp. Confidential- Prepared for Internal Use Only 3 AN_SY8009 Typical Performance Characteristics (SY8009B) Efficiency vs Load Current Efficiency vs Load Current Efficiency vs Load Current Output Ripple Output Ripple Output Ripple (Vin=5.0V, Vout=1.8V,Iload=0.5A) (Vin=5.0V, Vout=1.8V,Iload=1.5A) (Vin=5.0V, Vout=1.8V,Iload=2A) Startup Shutdown (Vin=5.0V, Vout=1.8V,Iload=2A) (Vin=5.0V, Vout=1.8V,Iload=2A) AN_SY8009 Rev. 0.71 Silergy Corp. Confidential- Prepared for Internal Use Only 4 AN_SY8009 Soft Start(Vo) Soft Start(Lx) Load Transient (Vin=5.0VmVout=1.8V,Iload=0~1A) Case Temperature vs Output Current Load Transient (Vin=5V,Vo=1.8V,Ta=27℃) Oscillator Frequency vs Vin TC(°C) (Vin=5.0V, Vout=1.8V,Iload=0.2~2A) AN_SY8009 Rev. 0.71 Silergy Corp. Confidential- Prepared for Internal Use Only 5 AN_SY8009 Operation SY8009 is a synchronous buck regulator IC that integrates the PWM control, top and bottom switches on the same die to minimize the switching transition loss and conduction loss. With ultra low RDS(ON) power switches and proprietary PWM control, this regulator IC can achieve the highest efficiency and the highest switch frequency simultaneously to minimize the external inductor and capacitor size, and thus achieving the minimum solution footprint. Applications Information Because of the high integration in the SY8009 IC, the application circuit based on this regulator IC is rather simple. Only input capacitor CIN, output capacitor COUT, output inductor L and feedback resistors (R1 and R2) need to be selected for the targeted applications specifications. 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 200k is highly recommended for R2. If R2=100k is chosen, then R1 can be calculated to be: R1 = (VOUT − 0.6 V) ⋅ R2 0.6V Input capacitor CIN: With the maximum load current at 1.2A, the maximum ripple current through input capacitor is about 0.6Arms. A typical X7R or better grade ceramic capacitor with 6V rating and greater than 4.7uF capacitance can handle this ripple current well. To minimize the potential noise problem, place this 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. 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 X7R or better grade ceramic capacitor with 6V rating and greater than 4.7uF capacitance. Output inductor L: There are several considerations in choosing this inductor. 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 output current. The inductance is calculated as: V (1 − VOUT /VIN, MAX ) L = OUT FSW × IOUT, MAX × 40% where Fsw is the switching frequency and IOUT,MAX is the maximum load current. The SY8009 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. VOUT(1-VOUT/VIN,MAX) ISAT, MIN > IOUT, MAX + 2 ⋅ FSW ⋅ L 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