BL9384 3A, 18V High Efficiency Synchronous Step-Down Converter FEATURES DESCRIPTION • • • • • • • • The BL9384 is a wide input range, highefficiency, DC-to-DC step-down switching regulator, capable of delivering up to 3A of output current. Current mode PWM control allows the use of small external components, such as ceramic input and output caps, as well as small inductors, while still providing low output ripples. On top of the integrated internal synchronous rectifier that eliminates external Schottky diode, Overall BL9384 is a highly efficient and robust solution for DC-DC step-down applications that requires wide input ranges. Wide Input Operating Range from 4.5V to 18V Capable of Delivering 3A No External Schottky Diode Needed Current Mode control 0.923V Reference for Low Output voltages Logic Control Shutdown Thermal shutdown and UVLO Available in ESOP8 Package APPLICATIONS • • • • BL9384 is available ESOP8 Packages. LCD TVs Notebook computers FPGA power supplies LED drivers TYPICAL APPLICATION PIN OUT www.belling.com.cn 1 BL9384 MARK and ORDERING INFORMATION Mark Explanation XX: Year YY: Week ZZ: Internal code PINOUT DESCRIPTION PIN # 1 2 3 4 5 6 7 8 NAME BST DESCRIPTION Bootstrap pin. Connect a 10nF capacitor from this pin to SW IN Supply Voltage. Bypass with a 22μF ceramic capacitor to GND SW Inductor Connection. Connect an inductor Between SW and the regulator output. GND Ground FB Feedback Input. Connect an external resistor divider from the output to FB and GND to set VOUT COMP Regulator Compensation. Connect series RC network to GND. EN Enable pin for the IC. Drive this pin to high to enable the part, low to disable. SS Soft start pin. Connect a 0.1 uF capacitor from this pin to GND BLOCK DIAGRAM www.belling.com.cn 2 BL9384 ABSOLUTE MAXIMUM RATING Parameter Value Input Voltage Range SW, EN Voltage BST Voltage FB Voltage SW to ground curren Operating Junction Temperature(Tj) ESOP-8L Package Thermal Resistance (θjc) Storage Temperature(Ts) -0.3V-20V –0.3V to VIN+0.3V –0.3V to SW+6V –0.3V to 6V Internally limited -40°C –85°C 10°C / W -40°C - 150°C Note: Exceed these limits to damage to the device. Exposure to absolute maximum rating conditions may affect device reliability. ELECTRICAL CHARACTERISTICS (VIN=12V, unless otherwise specified. Typical values are at TA=25°C) Symbol Parameter VDD Input Voltage Range UVLO_UP UVLO,IN UVLO Rising Vref Feedback Voltage Ifb Feedback Leakage current Iq Fsoc Conditions Min Typ 5 Rising, Hysteresis=140mV Max Unit 18 V 3.55 0.904 0.923 V 0.942 V 0.01 uA Active, Vfb=1V, No Switching 1 mA Shutdown Error Amp Transconductance 6 800 uA μS Current Sense Transresistance 0.2 Ω 340 KHz Quiescent Current Switching Frequency Ven=2V, Vin=12V RdsonP PMOS Rdson 120 mohm RdsonN NMOS Rdson 100 mohm Ilimit Peak Current Limit 3.5 A Ven EN Input Low Voltag Ien EN Input Current Isw SW Leakage Current TSD 1 VIN=12V,VSW=0 or 12V, EN= GND Over Temperature Proection www.belling.com.cn 1.5 V 1 μA 10 150 3 2 μA °C BL9384 TYPICAL PERFORMANCE CHARACTERISTICS (Vin=12V, Vout=3.3V, L=10uH, Cin=10uF, Cout=22uF, TA=25°C, unless otherwise stated) 3A load Switching waveform Start-up Waveform with Slow Vin Start-up Waveform with Fast Vin Load Transient Response VOUT 200mV/div VIN VIN VOUT VOUT ISW ISW 500mA/div ISW 100ms/div www.belling.com.cn 200µs/div 100ms/div 4 BL9384 FUNCTIONAL DECRIPTIONS Loop Operation The BL9384 is a wide input range, high-efficiency, DC-to-DC step-down switching regulator, capable of delivering up to 3A of output current, integrated with a 110mΩ synchronous MOSFET, eliminating the need for external diode. It uses a PWM current-mode control scheme. An error amplifier integrates error between the FB signal and the internal reference voltage. The output of the integrator is then compared to the sum of a current-sense signal and the slope compensation ramp. This operation generates a PWM signal that modulates the duty cycle of the power MOSFETs to achieve regulation for output voltage. Current Limit There is a cycle-by-cycle current limit on the high-side MOSFET of 3A(typ). When the current flowing out of SW exceeds this limit, the high-side MOSFET turns off and the synchronous rectifier turns on. Unlike the traditional method of current limiting by limiting the voltage at the compensation pin, which usually has large variation due to duty cycle variance, this type of peak current limiting scheme provides a relatively more accurate limit for output current, thereby lowering the requirements for system design. COMPONENT SELECTRION When setting up the BL9384 for different output voltage, please use following recommended component value for the best performance. VOUT (V) 8 5 3.3 2.5 1.8 1.2 COUT (µF) 22x2 22x2 22x2 22x2 22x2 22x2 www.belling.com.cn L (µH) 22 15 10 6.8 4.7 3.3 5 BL9384 PACKAGE OUTLINE Package ESOP8 Devices per reel 2500 Package specification： www.belling.com.cn 6 Unit mm