BL8030 450KHz, 16V, 2A Synchronous Step-Down Converter DESCRIPTION FEATURES The BL8030 is a fully integrated, high– efficiency 2A synchronous rectified step-down converter. The BL8030 operates at high efficiency over a wide output current load range. This device offers two operation modes, PWM control and PFM Mode switching control, which allows a high efficiency over the wider range of the load. The BL8030 requires a minimum number of readily available standard external components and is available in a 6-pin SOT23 ROHS compliant package. High Efficiency: Up to 96% 450KHz Frequency Operation 2A Output Current No Schottky Diode Required 3.5V to 16V Input Voltage Range 0.6V Reference Slope Compensated Current Mode Control for Excellent Line and Load Transient Response Integrated internal compensation Stable with Low ESR Ceramic Output Capacitors Over Current Protection with Hiccup-Mode Thermal Shutdown Inrush Current Limit and Soft Start Available in SOT23-6 -40°C to +85°C Temperature Range APPLICATIONS TYPICAL APPLICATION PIN OUT & MARKING C3 VIN 22nF L1 VIN 10uH BS SW C1 73k FB GND VOUT SW VIN EN 6 5 4 KAYW R1 EN 22uF Distributed Power Systems Digital Set Top Boxes Flat Panel Television and Monitors Wireless and DSL Modems Notebook Computer R2 C2 10k 22uF/6V 1 2 3 BS GND FB SOT23-6 KA: Product Code YW: Date code (Year & Week) www.belling.com.cn 1 BL8030 ORDERING INFORMATION PART No. PACKAGE Tape&Reel BL8030CB6TR SOT23-6 3000/Reel ABSOLUTE MAXIMUM RATING Parameter Value Supply Voltage VIN Switch Node Voltage VSW Boost Voltage VBS All Other Pins Operating Temperature Range Storage Temperature Range Lead Temperature (Soldering, 10s) -0.3V to 25V -0.3V to (VIN+0.5V) VSW-0.3V to VSW+5V -0.3V to 6V -40C to 85C -65C to 150C 300C ELECTRICAL CHARACTERISTICS (VIN=12V, VOUT=5V, TA=25C, unless otherwise stated) Parameter Conditions Input Voltage Range Min Typ 3.5 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 Thermal Shutdown VEN = 2.0V, VFB = 1.1V VEN = 0V or VEN = GND 4.5V≤VIN ≤18V 0.588 VEN = 0V, VSW = 0V Minimum Duty Cycle VFB = 0.6V 2 0.4 1 0.6 90 70 0 4.2 450 92 60 170 Max Unit 16 V 0.6 0.612 10 V mA uA V mΩ mΩ uA A KHz % ns °C PIN DESCRIPTION PIN # NAME 1 BS 2 GND 3 FB 4 EN 5 6 VIN SW www.belling.com.cn DESCRIPTION Boostrap. A capacitor connected between SW and BS pins is required to form a floating supply across the high-side switch driver. Ground Adjustable version feedback input. Connect FB to the center point of the external resistor divider. Drive this pin to a logic-high to enable the IC. Drive to a logic-low to disable the IC and enter micro-power shutdown mode. Power supply Pin Switching Pin 2 BL8030 ELECTRICAL PERFORMANCE Tested under, L=10uH, TA=25C, unless otherwise specified Efficiency vs. Iout Efficiency vs. Iout (Vout=1.2V) (Vout=3.3V) 90% 90% 80% 80% 70% 70% Efficiency(%) 100% Efficiency(%) 100% 60% 50% 40% Vin=5V Vin=9V Vin=12V Vin=16V 30% 20% 10% 60% 50% 40% Vin=5V Vin=9V Vin=12V Vin=16V 30% 20% 10% 0% 0% 0.0 0.5 1.0 Iout (A) 1.5 2.0 0.0 Efficiency vs. Iout 0.5 1.0 Iout (A) (Vout=1.2V) 100% 1.30 90% 1.25 80% 1.20 70% 1.15 60% Vout (V) Efficiency(%) 2.0 Vout vs. Iout (Vout=5.0V) 50% 40% 30% 10% 0.5 1.0 Iout (A) 1.5 1.05 Vin=5V Vin=9V Vin=12V Vin=16V 0.95 0.90 0% 0.0 1.10 1.00 Vin=9V Vin=12V Vin=16V 20% 0.0 2.0 0.5 3.45 5.15 3.40 5.10 3.35 5.05 3.30 5.00 Vout (V) 5.20 3.25 3.20 3.00 0.0 0.5 4.90 Vin=9V Vin=12V Vin=16V 4.80 4.75 4.70 1.0 1.5 2.0 0.0 Iout (A) www.belling.com.cn 4.95 4.85 Vin=5V Vin=9V Vin=12V Vin=16V 3.05 2.0 (Vout=5.0V) 3.50 3.10 1.5 Vout vs. Iout (Vout=3.3V) 3.15 1.0 Iout (A) Vout vs. Iout Vout (V) 1.5 0.5 1.0 Iout (A) 3 1.5 2.0 BL8030 Efficiency vs. Vin Vout vs. Vin Iout=1A Iout=1A 100.0% 5.10 Vout=5V 99.0% 5.05 98.0% 5.00 96.0% Vout (V) Efficiency(%) 97.0% 95.0% 94.0% 4.95 4.90 93.0% 92.0% 4.85 91.0% 90.0% 4.80 6 8 10 12 Vin (V) 14 16 6 8 10 12 Vin(V) 14 16 BLOCK DIAGRAM VIN + VCC Regulator - RSEN Current Sense Amplifier VCC BOOST Regulator Oscillator HS Driver SW + Current Limit Comparator EN BS Comparator On Time Control Logic Control VCC LS Driver Reference 1M + + FB www.belling.com.cn - GND Error Amplifier 4 BL8030 DETAILED DESCRIPTION Internal Regulator Startup and Shutdown The BL8030 is a current mode step down DC/DC converter that provides excellent transient response with no extra external compensation components. This device contains an internal, low resistance, high voltage power MOSFET, and operates at a high 600K operating frequency to ensure a compact, high efficiency design with excellent AC and DC performance. If both VIN and EN are higher than their appropriate thresholds, the chip starts. The reference block starts first, generating stable reference voltage and currents, and then the internal regulator is enabled. The regulator provides stable supply for the remaining circuitries. Three events can shut down the chip: EN low, VIN low and thermal shutdown. In the shutdown procedure, the signaling path is first blocked to avoid any fault triggering. The COMP voltage and the internal supply rail are then pulled down. The floating driver is not subject to this shutdown command. Error Amplifier The error amplifier compares the FB pin voltage with the internal FB reference (VFB) and outputs a current proportional to the difference between the two. This output current is then used to charge or discharge the internal compensation network to form the COMP voltage, which is used to control the power MOSFET current. The optimized internal compensation network minimizes the external component counts and simplifies the control loop design. APPLICATIONS INFORMATION Setting Output Voltages The external resistor divider is used to set the output voltage (see Typical Application on page 1). The feedback resistor R1 also sets the feedback loop bandwidth with the internal compensation capacitor. Choose R1 to be around 100kΩ for optimal transient response. R2 is then given by: Internal Soft-Start The soft-start is implemented to prevent the converter output voltage from overshooting during startup. When the chip starts, the internal circuitry generates a soft-start voltage (SS) ramping up from 0V to 0.6V. When it is lower than the internal reference (REF), SS overrides REF so the error amplifier uses SS as the reference. When SS is higher than REF, REF regains control. The SS time is internally fixed to 1ms. Over-Current-Protection and Hiccup Selecting the Inductor The BL8030 has cycle-by-cycle over current limit when the inductor current peak value exceeds the set current limit threshold. Meanwhile, output voltage starts to drop until FB is below the UnderVoltage (UV) threshold, typically 30% below the reference. Once a UV is triggered, the BL8030 enters hiccup mode to periodically restart the part. This protection mode is especially useful when the output is dead-short to ground. The average short circuit current is greatly reduced to alleviate the thermal issue and to protect the regulator. The BL8030 exits the hiccup mode once the over current condition is removed. A 4.7μH to 22μH inductor with a DC current rating of at least 25% percent higher than the maximum load current is recommended for most applications. For highest efficiency, the inductor DC resistance should be less than 15mΩ. For most designs, the inductance value can be derived from the following equation. www.belling.com.cn Where ΔIL is the inductor ripple current. Choose inductor ripple current to be approximately 30% if 5 BL8030 the maximum load current, 2A. The maximum inductor peak current is: dominated by the capacitance. The output voltage ripple is mainly caused by the capacitance. For simplification, the output voltage ripple can be estimated by: Under light load conditions below 100mA, larger inductance is recommended for improved efficiency. Selecting the Output Capacitor In the case of tantalum or electrolytic capacitors, the ESR dominates the impedance at the switching frequency. For simplification, the output ripple can be approximated to: The output capacitor (C2) is required to maintain the DC output voltage. Ceramic, tantalum, or low ESR electrolytic capacitors are recommended. Low ESR capacitors are preferred to keep the output voltage ripple low. The output voltage ripple can be estimated by: The characteristics of the output capacitor also affect the stability of the regulation system. The BL8030 can be optimized for a wide range of capacitance and ESR values. Where L is the inductor value and RESR is the equivalent series resistance (ESR) value of the output capacitor. In the case of ceramic capacitors, the impedance at the switching frequency is PACKAGE OUTLINE Package SOT23-6 Devices per reel Package specification： www.belling.com.cn 6 3000 Unit mm