HG1484M/TR

HG1484 3A 27V Synchronous Buck Converter Description Features The HG1484 is a monolithic synchronous buck regulator. The device integrates 90 mΩ MOSFETS that provide 3A continuous load current over a wide operating input voltage of 4.5V to 27V. Current mode control provides fast transient response and cycle- by-cycle current limit. An adjustable soft-start prevents inrush current at turn on.            3A Output Current Wide 4.5V to 27V Operating Input Range Fixed 340KHZ Frequency Integrated Power MOSFET switches Output Adjustable from 0.925V to 0.8Vin Up to 93% Efficiency Programmable Soft-Start Stable with Low ESR Ceramic Output Capacitors Cycle by Cycle Over Current Protection Short Circuit Protection Input Under Voltage Lockout Package： ESOP-8L Applications      Distributed Power Systems Networking Systems FPGA, DSP, ASIC Power Supplies Green Electronics/ Appliances Notebook Computers Typical Application Circuit http://www.hgsemi.com.cn 1 2018 AUG HG1484 Pin Assignments Pin Descriptions Pin Number Name 1 BS 2 VIN 3 SW 4 GND 5 FB 6 COMP 7 EN 8 SS Description Bootstrap. This pin acts as the positive rail for the high-side switch’s gate driver. Connect a 0.01uF capacitor between BS and SW. Input Supply. Bypass this pin to GND with a low ESR capacitor. See Input Capacitor in the Application Information section. Switch Output. Connect this pin to the switching end of the inductor. Ground. Feedback Input. The voltage at this pin is regulated to 0.925V.Connect to the resistor divider between output and ground to set output voltage. Pin. See Stability Compensation in the Application Information Compensation section. Enable Input. When higher than 2.7V, this pin turns the IC on. When lower than 1.1V, this pin turns the IC off. Output voltage is discharged when the IC is off. This pin should not be left open. Recommend to put a 150K Control -up resistor to controls Vin for startup. Soft-Start Input. SS the soft-start period. Connect a capacitor from SS to GND to set the soft-start period. A 0.1uF capacitor sets the soft-start period to 13ms. To disable the soft-start Pad. SS Need to connect to GND pin. feature, leave unconnected. Exposed Pad Exposed http://www.hgsemi.com.cn 2 2018 AUG HG1484 Block Diagram Absolute Maximum Ratings Parameter Value Unit -0.3 to 30 V SW Voltage -0.3 to VIN + 0.3 V BS Voltage VSW – 0.3 to VSW + 6 V EN, FB, COMP Voltage -0.3 to 5 V Continuous SW Current Internally limited A 20 °C/W 10 °C/W Internally limited W 150 °C -65 to 150 °C Input Supply Voltage Junction to Ambient Thermal Resistance (θJA) (Test on Approximately 3 in2 Copper Area 1oz copper FR4 board) (Test on Approximately 3 inResistance Copper Area Junction to Ambient Case (θ 1oz ) copper FR4 board) JC SOP-8L Power Dissipation Maximum Junction Temperature Storage Temperature Range Moisture Sensitivity (MSL) Please refer the MSL label on the IC package bag/carton for detail (Note: Exceeding these limits may damage the device. Even the duration of exceeding is very short. http://www.hgsemi.com.cn 3 2018 AUG HG1484 Exposure to absolute maximum rating conditions for long periods may affect device reliability.) Recommended Operating Conditions Parameter Min Input Supply Voltage 4.5 Operating Junction Temperature -20 Max Unit (1) 27 27 (2) +125 V °C (Note (1): Operating the IC over this voltage is very easy to cause over voltage condition to VIN pin, SW pin, BS pin & EN pin) (Note (2): If the IC experienced OTP, then the temperature may need to drop to 15V, pure ceramic Cin (* no EC cap) is not recommended. This is because the ESR of a ceramic cap is often too small, pure ceramic Cin will work with the parasite inductance of the input trace and forms a VIN resonant tank. When VIN is hot plug in/out, this resonant tank will boost the Vin spike to a very high voltage and damage the IC. Output Capacitor The output capacitor also needs to have low ESR to keep low output voltage ripple. In the case of ceramic output capacitors, RESR is very small and does not contribute to the ripple. Therefore, a lower capacitance value can be used for ceramic capacitors. In the case of tantalum or electrolytic capacitors, the ripple is dominated by RESR multiplied by the ripple current. In that case, the output capacitor is chosen to have sufficiently low ESR. For ceramic output capacitors, typically choose two capacitors of about 22uF. For tantalum or electrolytic capacitors, choose a capacitor with less than 50mΩ ESR. Optional Schottky Diode During the transition between high-side switch and low-side switch, the body diode of the low side power MOSFET conducts the inductor current. The forward voltage of this body diode is high. An optional Schottky diode may be paralleled between the SW pin and GND pin to improve overall efficiency. Table 3 lists example Schottky diodes and their Manufacturers. Table 3－Diode Selection Guide Vin max Part Number Voltage/Current Rating 20V B130 SK13 B140 SK14 30V, 1A 30V, 1A 40V,1A 40V, 1A http://www.hgsemi.com.cn 7 Vendor 2018 AUG HG1484 Stability Compensation CCOMP2 is needed only for high ESR output capacitor Figure2. Stability Compensation The feedback loop of the IC is stabilized by the components at the COMP pin, as shown in Figure2. The DC loop gain of the system is determined by the following equation: The dominant pole P1 is due to CCOMP1: The second pole P2 is the output pole: The first zero Z1 is due to RCOMP and CCOMP1: And finally, the third pole is due to RCOMP and CCOMP2 (if CCOMP2 is used): The following steps should be used to compensate the IC: STEP1. Set the crossover frequency at 1/10 of the switching frequency via RCOMP: But limit RCOMP to 10KΩ maximum. More than 10 KΩ is easy to cause overshoot at power on. STEP2. Set the zero fZ1 at 1/4 of the crossover frequency. If RCOMP is less than 10KΩ, the equation for CCOMP is: http://www.hgsemi.com.cn 8 2018 AUG HG1484 STEP3. If the output capacitor’s ESR is high enough to cause a zero at lower than 4 times the crossover frequency, an additional compensation capacitor CCOMP2 is required. The condition for using CCOMP2 is: And the proper value for CCOMP2 is: Though CCOMP2 is unnecessary when the output capacitor has sufficiently low ESR, a small value CCOMP2 such as 100pF may improve stability against PCB layout parasitic effects. Table 4 Component Selection Guide for Stability Compensation Vout(V) 5 – 12 1.0 2.4 6.8 none 4.7 5 – 15 1.2 3 6.2 none 4.7 5 – 15 1.8 6.2 3 none 10 5 – 15 2.5 8 2.2 none 10 5 – 15 3.3 10 2.2 none 10 7 – 15 5 10 2.2 none 10 5 – 12 1.0 5 – 15 1.2 5 – 23 1.8 5 – 27 10 10 680 10 2.5 5 – 27 3.3 7 – 27 5 http://www.hgsemi.com.cn Cout Rcomp(kΩ) Ccomp(nF) Ccomp2(pF) Inductor(uH) Vin Range (V) 22uF x2 Ceramic 470uF/ 6.3V/ 120mΩ 9 2018 AUG HG1484 Figur3. Load Transient Testing VS Compensation Value Typical Performance Characteristics (VIN=12V, Io=0 mA, Temperature = 25 degree C, unless otherwise specified) Light Load Operation (No load) Heavy Load Operation (3A Load) VIN=12V, Iin=8.2 mA, Vout=3,3V VIN=12V, Vout=3,3V Startup VIN=12V, Vout=3.3V, Iout=1A through Vin. http://www.hgsemi.com.cn through Enable. 10 2018 AUG HG1484 Startup Vin=12V, Vout=3.3V, Iout=1A through Vin. http://www.hgsemi.com.cn through Enable. 11 2018 AUG HG1484 http://www.hgsemi.com.cn 12 2018 AUG HG1484 Important statement: Huaguan Semiconductor Co,Ltd. reserves the right to change the products and services provided without notice. Customers should obtain the latest relevant information before ordering, and verify the timeliness and accuracy of this information. Customers are responsible for complying with safety standards and taking safety measures when using our products for system design and machine manufacturing to avoid potential risks that may result in personal injury or property damage. Our products are not licensed for applications in life support, military, aerospace, etc., so we do not bear the consequences of the application of these products in these fields. Our documentation is only permitted to be copied without any tampering with the content, so we do not accept any responsibility or liability for the altered documents. http://www.hgsemi.com.cn 13 2018 AUG