BL8034CS8TR

BL8034 4A, 16V High Efficiency Synchronous Step-Down Converter DESCRIPTION FEATURES The BL8034 is a wide input range, high-efficiency, DC-to- DC step-down switching regulator, capable of delivering up to 4A 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, BL8034 also employs a proprietary control scheme that switches the device into a power save mode during light load, thereby extending the range of high efficiency operation. Therefore, BL8034 is a much superior solution in comparison to other competitions in terms of efficiency and cost. Overall, BL8034 is a highly efficient and robust solution for DC-DC step-down applications that requires wide input ranges.           Wide Input Operating Range from 4.2V to 16V High Efficiency: Up to 95% at Light Load Capable of Delivering 4A No external Schottky Diode Needed Inductor Short Circuit Protection Current Mode Control 0.923V Reference for Low Output Voltages Logic Control Shutdown Thermal Shutdown and UVLO Available inESOP8 Package APPLICATIONS     LCD TVs Notebook computers FPGA power supplies LED drivers The BL8034 is available in ESOP8 package. TYPICAL APPLICATION MARK and PIN OUT C3 VIN BST NC 1uF L C1 Ren 22uF 100k VIN EN BST SW 3.3V/4A VOUT R1 LC2334 BL8034 GND VIN 4.7uH SW GP LLDYW GND 257k EN NC FB C2 FB R2 22uF ESOP8 100k ORDERING INFORMATION Mark Explanation GP: Product Code LL: Lot No. D: Fab code YW: Date code www.belling.com.cn 1 Ordering Information ESOP8 2500pcs/reel BL8034CS8TR BL8034 PINOUT DESCRIPTION PIN # 1 2 3 4 5 6 7 8 NAME BST VIN SW GND FB NC EN NC DESCRIPTION High side power transistor gate drive boost input. Power input. Bypass with a 10uF~22uF ceramic capacitor to GND. Power switching node to connect inductor. Ground. Feedback input with reference voltage set to 0.923V. No connection Enable input. Set this pin to high level to enable the part, low level to disable. No connection ABSOLUTE MAXIMUM RATING Parameter Value Input Voltage SW.EN Voltage BST Voltage FB Voltage SW to ground current Ambient Temperature(Ta) Storage Temperature(Ts) -0.3V to 17V -0.3V to VIN +0.3V -0.3V to SW+6V -0.3V to 6V Internally limited -40C - 85C -55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, VOUT=5V, TA=25C, unless otherwise stated) Parameter Input Voltage Range UVLO Threshold Supply Current in Operation Supply Current in Shutdown Regulated Feedback Voltage High-side Switch On Resistance Low-side Switch On Resistance High-side Switch Leakage Current Upper Switch Current Limit Oscillation Frequency Maximum Duty Cycle Minimum On Time EN Input Voltage “H” EN Input Voltage “L” Thermal Shutdown www.belling.com.cn Conditions Min Typ 4.2 VEN = 2.0V, VFB = 1.1V VEN = 0V or VEN = GND 4.2V≤VIN ≤16V VBST-SW = 5V VIN = 5V VEN = 0V, VSW = 0V Minimum Duty Cycle 0.904 VFB = 0.8V 4.1 0.5 5 0.923 120 60 0 6 500 92 100 Max Unit 16 V V mA uA V mΩ mΩ uA A KHz % ns V V °C 10 0.942 10 1.5 0.6 160 2 BL8034 TYPICAL PERFORMANCE CHARACTERISTICS (L=4.7uH, Cin=22uF, Cout=22uF, TA=25C, unless otherwise stated) Efficiency vs. Iout Efficiency vs. Iout Vout=3.3V 100% 100% 90% 90% 80% 80% 70% 70% Efficiency(%) Efficiency(%) Vout=1.2V 60% 50% 40% 30% 60% 50% 40% 30% 20% 0% 0 1 2 Iout (A) 3 Vin=6V Vin=12V Vin=16V 20% Vin=6V Vin=12V Vin=16V 10% 10% 0% 4 0 Efficiency vs. Iout 1 3 4 Output Voltage vs. Iout Vout=5.0V Vout=1.2V 100% 1.30 90% 1.25 80% 1.20 70% 1.15 60% 1.10 Vout (V) Efficiency(%) 2 Iout (A) 50% 40% 1.05 1.00 0.95 30% 20% 0.90 Vin=6V Vin=12V Vin=16V 10% 0% 0 1 2 Iout (A) 3 Vin=6V Vin=12V Vin=16V 0.85 0.80 0 4 1 2 3 4 Iout (A) Output Voltage vs. Iout Output Voltage vs. Iout Vout=3.3V Vout=5.0V 4.0 6.0 3.5 5.0 3.0 4.0 Vout (V) Vout (V) 2.5 2.0 1.5 3.0 2.0 1.0 Vin=6V Vin=12V Vin=16V 0.5 0.0 0 1 2 3 0.0 4 0 Iout (A) www.belling.com.cn Vin=6V Vin=12V Vin=16V 1.0 1 2 Iout (A) 3 3 4 BL8034 Vout vs. Vin Vout vs. Vin Iout=1A 4.0 4.0 3.5 3.5 3.0 3.0 2.5 2.5 Vout (V) Vout (V) Iout=0 2.0 2.0 1.5 1.5 1.0 1.0 0.5 0.5 0.0 0.0 4 8 12 16 4 Vin(V) 8 12 16 Vin(V) FUNCTIONAL DECRIPTIONS Loop Operation The BL8034 is a wide input range, high-efficiency, DC-toDC step-down switching regulator, capable of delivering up to 4A of output current, integrated with a 120/60m synchronous MOSFET pair, 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. light load, thereby extending the range of high efficiency operation. PCB LAYOUT RECOMMENDATION The device’s performance and stability are dramatically affected by PCB layout. It is recommended to follow these general guidelines shown as below: 1. Place the input capacitors and output capacitors as close to the device as possible. The traces which connect to these capacitors should be as short and wide as possible to minimize parasitic inductance and resistance. 2. Place feedback resistors close to the FB pin. 3. Keep the sensitive signal (FB) away from the switching signal (SW). 4. The exposed pad of the package should be soldered to an equivalent area of metal on the PCB. This area should connect to the GND plane and have multiple via connections to the back of the PCB as well as connections to intermediate PCB layers. The GND plane area connecting to the exposed pad should be maximized to improve thermal performance. 5. Multi-layer PCB design is recommended. Current Limit There is a cycle-by-cycle current limit on the high-side MOSFET of 6A(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. Light Load Operation Traditionally, a fixed constant frequency PWM DC-DC regulator always switches even when the output load is small. When energy is shuffling back and forth through the power MOSFETs, power is lost due to the finite RDSONs of the MOSFETs and parasitic capacitances. At light load, this loss is prominent and efficiency is therefore very low. BL8034 employs a proprietary control scheme that improves efficiency in this situation by enabling the device into a power save mode during www.belling.com.cn 4 BL8034 PACKAGE OUTLINE Package ESOP8 Devices per reel 2500 Package specification： www.belling.com.cn 5 Unit mm