SY8512FCC

Application Note: SY8512 High Efficiency, 100V Input, 2A Asynchronous Step Down Regulator General Description Features • The SY8512 develops a high efficiency, current mode adaptive constant off time controlled, asynchronous step-down DC/DC converter capable of delivering 2A output current. The SY8512 operates over a wide input voltage range from 4.5V to 100V and integrates main switch with very low RDS(ON) to minimize the conduction loss. The switching frequency is adjustable from 100kHz to 1MHz using an external resistor. And the device features cycle-by-cycle peak current limitation. dF Applications Non-isolated Telecommunication Buck Regulator Secondary High Voltage Post Regulator Automotive Systems Electric Bicycle rep are • • • • Note -- de nti a lP Package type SO8E or W • • • • • • SY8512 □(□□)□ Ordering Number SY8512FCC OO KO O • • • Ordering Information Temperature Code Package Code Optional Spec Code Low RDS(ON) for Internal N-channel Power FET(TOP):175mΩ 4.5-100V Input Voltage Range 2A Output Current Capability Adjustable Switching Frequency Range: 100kHz to1MHz Internal Soft-start Limits the Inrush Current Hic-cup Mode Output Short Circuit Protection EN ON/OFF Control with Accurate Threshold Cycle-by-cycle Peak Current Limit 0.8V±1% Reference Voltage Accuracy Compact Package: SO8E LX CIN RPG ON/ OFF orp IN EN yC GND erg Sil COUT 60 50 40 30 VIN =12V, VOUT=5V VIN =24V, VOUT=5V VIN =48V, VOUT=5V VIN =72V, VOUT=5V 10 0 0.001 0.01 0.1 1 2 Output Current (A) Figure1. Schematic Diagram AN_SY8512 Rev. 0.9 © 2022 Silergy Corp. CFF 70 20 R2 FS RFS R1 FB PG 90 VOUT .C VIN 100 80 L1 BS Efficiency vs. Output Current (fSW =200kHz, L=22μH/PCMB104T-220MS) Efficiency (%) CBS on fi Typical Applications Figure2. Efficiency vs. Output Current Silergy Corp. Confidential- Prepared for Customer Use Only 1 All Rights Reserved. SY8512 Pinout (top view) 1 EN 2 FS 3 GND 4 8 LX 7 BS 6 PG 5 FB Exposed Pad OO KO O IN (SO8E) de nti a lP rep are dF or W Top Mark: BXBxyz (Device code: BXB; x=year code, y=week code, z= lot number code) Pin Name Pin Number Pin Description IN 1 Input pin. Decouple this pin to the GND pin with at least a 1μF ceramic capacitor. EN 2 Enable control. Pulled high to turn on. Do not leave it floating. Frequency programming pin. Connect a resistor to ground to program a switching FS 3 frequency between 100kHz to 1MHz. The switching frequency equals to: fsw(kHz)=105/RFS(kΩ) GND 4 Ground pin Output feedback pin. Connect this pin to the center point of the output resistor FB 5 divider (as shown in Figure 1) to program the output voltage: VOUT=0.8×(1+R1/R2). Power good Indicator. Open-drain output when the output voltage is within 90% PG 6 to120% of the regulation point. Boot-strap pin. Supply high side gate driver. Connect a 0.1μF ceramic capacitor BS 7 between the BS pin and the LX pin. LX 8 Inductor pin. Connect this pin to the switching node of the inductor. Exposed Exposed pad must be connected to the GND pin. Connect to system ground plane / Pad on application board for optimal thermal performance. .C on fi Block Diagram EN erg Sil FB Input UVLO Current Limitation VCC BS Power FET LX Enable Threshold OFF Timer FS Current Sense Comp VCC yC orp Internal Power IN PWM Control & Protection Logic OTP SCP PG Internal SST VREF GND EA Figure3. Block Diagram AN_SY8512 Rev. 0.9 © 2022 Silergy Corp. Silergy Corp. Confidential- Prepared for Customer Use Only 2 All Rights Reserved. SY8512 Absolute Maximum Ratings (Note 1) Recommended Operating Conditions (Note 3) or W OO KO O Supply Input Voltage ---------------------------------------------------------------------------------------------- -0.3V to 100V BS-LX Voltage ------------------------------------------------------------------------------------------------------- -0.3V to 6V EN, FS, FB, PG, LX Voltage ------------------------------------------------------------------------------ -0.3V to VIN + 0.3V Power Dissipation, PD @ TA = 25°C, SO8E -------------------------------------------------------------------------------2.38W Package Thermal Resistance (Note 2) θ JA ------------------------------------------------------------------------------------------------------------------42°C/W θ JC -------------------------------------------------------------------------------------------------------------------4°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 Dynamic LX voltage in 10 ns duration ------------------------------------------------------------------ VIN + 3V to GND-5V Sil erg yC orp .C on fi de nti a lP rep are dF Supply Input Voltage ------------------------------------------------------------------------------------------------ 4.5V to 100V Junction Temperature Range ------------------------------------------------------------------------------------ -40°C to 125°C Ambient Temperature Range -------------------------------------------------------------------------------------- -40°C to 85°C AN_SY8512 Rev. 0.9 © 2022 Silergy Corp. Silergy Corp. Confidential- Prepared for Customer Use Only 3 All Rights Reserved. SY8512 Electrical Characteristics (VIN =48V, VOUT = 5V, L =10μH, COUT = 22μF, TA = 25°C, IOUT =1A unless otherwise specified) Symbol VIN VUVLO VHYS IQ ISHDN VREF IFB RDS(ON) VEN,R VEN,F IEN tON,MIN tOFF,MIN tSS Test Conditions Switching Frequency Program Range fSW,RNG RFS=100k~1M 100 Switching Frequency Setting Accuracy fSW RFS=200k 400 tPG_F tPG_R VPG,L UVP Hiccup ON Time yC .C orp Power Good Output Low PG High Leakage Current Top FET Current Limit Output Under Voltage Protection Threshold Output UVP Delay (Note4) on fi Power Good Delay (Note4) Sil erg UVP Hiccup OFF Time Thermal Shutdown Temperature (Note4) Thermal Shutdown Hysteresis (Note4) 2 792 -50 1 0.8 -1 Typ 4.2 0.3 100 8 800 rep are 175 1.1 0.9 Max 100 4.5 130 16 808 50 1.2 1 1 180 280 2 dF or W VFB=3.3V VFB falling, PG from high to low VFB rising, PG from low to high VFB rising, PG from high to low VFB falling, PG from low to high High to low Low to high IPG=2mA 500 kHz 600 kHz 0.3 1 ILMT,RNG 3 VUVP 45 50 Unit V V V µA µA mV nA mΩ V V µA ns ns ms 1000 90 92 120 115 20 200 lP VPG VFB=VREF×105% VEN=0V de nti a Power Good Threshold Min 4.5 3.9 OO KO O Parameter Input Voltage Range Input UVLO Threshold Input UVLO Hysteresis Quiescent Current Shutdown Current Feedback Reference Voltage FB Input Current Top FET RON EN Rising Threshold EN Falling Threshold EN Leakage Current Min ON Time (Note4) Min OFF Time (Note4) Soft-start Time 55 %VREF %VREF %VREF %VREF µs µs V µA A %VREF tUVP,DLY 10 µs tUVP,ON 2 ms tUVP,OFF 16 ms TSD 150 ˚C THYS 15 ˚C Note 1: Stresses beyond “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 affect device reliability. Note 2: θ JA is measured in the natural convection at TA = 25°C on a two-layer Silergy demo board. Note 3: The device is not guaranteed to function outside its operating conditions. Note 4: Based on simulation result. AN_SY8512 Rev. 0.9 © 2022 Silergy Corp. Silergy Corp. Confidential- Prepared for Customer Use Only 4 All Rights Reserved. SY8512 Typical Performance Characteristics Efficiency vs. Output Current Load Regulation (fSW =200kHz, L=22μH/PCMB104T-220MS) 100 5.07 90 70 60 50 40 30 VIN =12V, VOUT=5V VIN =24V, VOUT=5V VIN =48V, VOUT=5V VIN =72V, VOUT=5V 20 10 5.05 5.04 5.03 5.02 5.01 0.01 0.1 1 or W 0 0.001 OO KO O Output Voltage (V) Efficiency (%) VIN=12V VIN=24V VIN=48V VIN=72V 5.06 80 0 2 0.2 dF Output Ripple rep are (VIN =48V, VOUT=5V, IOUT=0A) 50mV/div VOUT 20V/div IL 1A/div 0.8 1.0 1.2 1.4 1.6 1.8 2.0 Output Ripple (VIN =48V, VOUT=5V, IOUT=2A) 50mV/div VLX 20V/div IL 2A/div on fi de nti a lP VLX 0.6 Output Current (A) Output Current (A) VOUT 0.4 Load Transient Time (10µs/div) .C Time (20ms/div) orp (VIN =48V, VOUT=5V, IOUT=0.2~2A) 200mV/div erg yC VOUT 1A/div Sil IL Time (400µs/div) AN_SY8512 Rev. 0.9 © 2022 Silergy Corp. Silergy Corp. Confidential- Prepared for Customer Use Only 5 All Rights Reserved. SY8512 Startup from VIN Shutdown from VIN (VIN =48V, VOUT=5V, IOUT=0A) (VIN =48V, VOUT=5V, IOUT=0A) 50V/div VIN VOUT 5V/div VOUT 5V/div VLX 50V/div VLX 50V/div IL 1A/div IL 1A/div or W OO KO O VIN dF Time (2ms/div) Startup from VIN 5V/div VLX 50V/div IL 2A/div Startup from EN .C Time (2ms/div) 5V/div VLX 50V/div IL 1A/div 5V/div VLX 50V/div IL 2A/div Shutdown from EN erg VOUT VOUT (VIN =48V, VOUT=5V, IOUT=0A) Sil 5V/div Time (2ms/div) AN_SY8512 Rev. 0.9 © 2022 Silergy Corp. 50V/div Time (40ms/div) yC orp (VIN =48V, VOUT=5V, IOUT=0A) VEN VIN de nti a VOUT Shutdown from VIN (VIN =48V, VOUT=5V, IOUT=2A) lP 50V/div on fi VIN Time (40ms/div) rep are (VIN =48V, VOUT=5V, IOUT=2A) 50V/div VEN 5V/div VOUT 5V/div VLX 50V/div IL 1A/div Time (1s/div) Silergy Corp. Confidential- Prepared for Customer Use Only 6 All Rights Reserved. SY8512 Startup from EN Shutdown from EN (VIN =48V, VOUT=5V, IOUT=2A) (VIN =48V, VOUT=5V, IOUT=2A) 5V/div VEN 5V/div VOUT 5V/div VOUT 5V/div VLX 50V/div IL 2A/div OO KO O VEN or W Time (2ms/div) dF rep are 1A/div lP IL de nti a 5V/div 50V/div IL 2A/div Time (2ms/div) Short Circuit Protection Short Circuit Protection (VIN =48V, VOUT=5V, IOUT=0A~short) VOUT VLX VOUT 5V/div IL 1A/div Time (10ms/div) Sil erg yC orp .C on fi Time (10ms/div) (VIN =48V, VOUT=5V, IOUT=2A~short) AN_SY8512 Rev. 0.9 © 2022 Silergy Corp. Silergy Corp. Confidential- Prepared for Customer Use Only 7 All Rights Reserved. SY8512 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 an X5R or better grade ceramic capacitor greater than 22μF capacitance. Operation Description OO KO O The SY8512 develops a high efficiency, current mode adaptive constant off time controlled, asynchronous step-down DC/DC converter capable of delivering 2A output current. The SY8512 operates over a wide input voltage range from 4.5V to 100V and integrates main switch with very low RDS(ON) to minimize the conduction loss. The switching frequency is adjustable from 100kHz to 1MHz using an external resistor. And the device features cycle-by-cycle peak current limitation. Applications Information on fi R2 yC GND R1 orp FB .C VOUT Sil erg Input Capacitor CIN: The ripple current through the input capacitor is calculated as： ICIN, RMS =IOUT  D(1-D) To minimize the potential noise problem, a typical X5R or better grade ceramic capacitor should be placed really close to the IN and the GND pins. Care should be taken to minimize the loop area formed by CIN, and the IN/GND pins. In this case, a 1μF low ESR ceramic capacitor is recommended. AN_SY8512 Rev. 0.9 © 2022 Silergy Corp. VOUT (1 − VOUT /VIN,MAX ) dF fSW  IOUT,MAX  40% rep are Where fsw is the switching frequency and the IOUT,MAX is the maximum load current. de nti a Feedback Resistor Dividers R1 and R2: Choose R1 and R2 to program the proper output voltage. To minimize the power consumption under light load, it is desirable to choose large resistance values for both R1 and R2. A value of between 10kΩ and 1MΩ is highly recommended for both resistors. If VOUT is 5V, R1=105kΩ is chosen, then using the following equation, R2 can be calculated to be 20kΩ: VFB R2 = R1 , VFB is typical 0.8V. VOUT -VFB L= The SY8512 regulator 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. lP Because of the high integration in the SY8512, the application circuit based on this IC is rather simple. Only the input capacitor CIN, the output capacitor COUT, the output inductor L1 and the feedback resistors (R1 and R2) need to be selected for the target applications. or W 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: 2) The saturation current rating of the inductor must be selected to be greater than the peak inductor current under full load conditions. ISAT, MIN  IOUT, MAX + 3) VOUT(1-VOUT/VIN,MAX) 2  fSW  L 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