BL8536 0.9V Startup, 1MHz, 300mA Iout, Low Iq, Synchronous Boost Converter DESCRIPTION FEATURES The BL8536 is a step-up converter that provides a boosted output voltage from a low voltage source. Because of its proprietary design, it starts up at a very low input voltage down to 0.9V, and only consumes 15uA at standby, making it an ideal choice for single cell alkaline/NiMH battery operations. A switching frequency of 1MHz minimizes solution footprint by allowing the use of tiny, low profile inductors and ceramic capacitors. The current mode PWM design is internally compensated, reducing external parts count. BL8536 is available in SOT23-3、SOT23-5 and SOT89-3 Packages. Efficiency up to 95%@Vin=2.7V, Vout=3.3V Typical 15uA standby current 1MHz Switching Frequency allows small inductor and output cap Input boost-strapping allows using small or no input cap Low Vin Start-up Voltage down to 0.9V Ideal for Single Alkaline Cell operations Maximum Output Current up to 300mA Low Noise PWM control Internally Compensated Current Mode Control Internal Synchronous Rectifier Available in SOT23-3、SOT23-5 and SOT89-3 APPLICATIONS One to Three Cell Battery Operated Devices Medical Instruments Bluetooth Headsets Flash-Based MP3 Players Noise Canceling Headphones TYPICAL APPLICATION PIN OUT & MARKING OUT OUT SW 3 5 4 2.2uH SXX LLHYW SXYW SXYW SW VIN VOUT 1 GND OUT 10uF LC3500 BL8536 2 SW 1 2 3 1 2 3 NC GND NC GND OUT SW SOT23-3 10uF SOT23-5 SOT89-3 S: Product Code X: Output Voltage YW: Date code GND S: Product Code XX: Output Voltage LL: LOT No. H: FAB Code YW: Date code Output Voltage Code X： www.belling.com.cn 1 VOUT Code VOUT 1.8V 8 2.8V Code 2.2V 3.0V 0 2.5V 3.3V 3 2.7V 3.6V 6 BL8536 ORDERING INFORMATION PART No. BL8536CB3TR□□ BL8536CB5TR□□ BL8536CC3TR□□ Note: □□stands for output voltage. PACKAGE Tape&Reel SOT23-3 SOT23-5 SOT89-3 3000/Reel 3000/Reel 1000/Reel ABSOLUTE MAXIMUM RATING Parameter Value SW Voltage -0.3 ~ 6V OUT Voltage -0.3 ~ 6V Max Operating Junction Temperature(Tj) 125C SOT23-3 450mW Maximum Power Dissipation SOT23-5 450mW SOT89-3 500mW Ambient Temperature(Ta) -40C – 85C Storage Temperature(Ts) -55C - 150C Lead Temperature & Time 260C, 10S Note: Exceed these limits to damage to the device. Exposure to absolute maximum rating conditions may affect device reliability. ELECTRICAL CHARACTERISTICS (TA=25C) Symbol Vin Parameter Conditions Input Voltage Range Min Typ 0.9 Vstart Startup Voltage Iout = 1mA 0.9 Vhold Hold Voltage Iout = 50mA 0.5 Vout Output Voltage Range Fsoc IQ 1.8 Unit 5 V V 0.7 3.6 V V Output voltage accuracy Iout = 0mA 2 Line regulation Iout = 50mA 0.1 Load regulation Iout = 0~300mA 1 2 % Switching Frequency Vout=0.95Vo, No inductor 0.7 1 1.4 MHz Max Duty cycle Vout=0.95Vo, No inductor 85 90 95 % Quiescent Current at Vout Vout=1.05*Vo 5 8 15 uA Supply current at Vin Iout = 0mA 20 uA Efficiency RdsonP PMOS Rdson Iout = 100mA Isw =100mA RdsonN NMOS Rdson Isw =100mA SW Leakage Current Vout=3.6V, Vsw=0 or 5.2V Iswlk Max % 0.2 85 %/V % 400 600 mohm 200 300 mohm 1 uA PIN DESCRIPTION PIN # NAME DESCRIPTION GND SW Ground To connect inductor to VIN Output voltage pin, with 10uF ceramic capacitor closely connected to GND No Connection SOT23-3 1 2 SOT23-5 2 4 SOT89-3 1 3 3 5 2 OUT - 1, 3 - NC www.belling.com.cn 2 BL8536 ELECTRICAL PERFORMANCE Tested under Cin=Cout=10uF, L=2.2uH, TA=25C, unless otherwise specified Efficiency vs. Output Current 100% 80% 80% 60% 60% 40% Vin=1.0V Vin=1.5V Vin=2.0V Vin=2.7V 20% 0% 0.001 0.01 Iout (A) (Vout=3.0V) 100% Efficiency Efficiency Efficiency vs. Output Current (Vout=3.3V) 0.1 40% 0% 0.001 1 Efficiency vs. Output Current 60% 60% Efficiency Efficiency 80% 40% 0% 0.001 Vin=1.0V Vin=1.2V Vin=1.5V Vin=2.0V 40% Iout (A) 0.1 2.5 2.5 Vout (V) Vout (V) 3.0 3.0 2.0 Vin=1.0V Vin=1.5V Vin=2.0V Vin=2.7V 1.0 0.5 0.0 0.4 0.6 Iout (A) 0.8 0.1 1 2.0 1.5 Vin=1.0V Vin=1.5V Vin=2.0V Vin=2.7V 1.0 0.5 0.0 1 0 Output Voltage vs. Output Current 0.2 0.4 0.6 0.8 Iout (A) 1 1.2 Output Voltage vs. Output Current (Vout=2.2V) 3.0 Iout (A) (Vout=3.0V) 3.5 3.5 1.5 0.01 Output Voltage vs. Output Current (Vout=3.3V) 0.2 Vin=1.0V Vin=1.2V Vin=1.5V 0% 0.001 1 Output Voltage vs. Output Current 0 1 20% 0.01 4.0 0.1 Iout (A) (Vout=1.8V) 100% 80% 20% 0.01 Efficiency vs. Output Current (Vout=2.2V) 100% Vin=1.0V Vin=1.5V Vin=2.0V Vin=2.7V 20% (Vout=1.8V) 2.0 2.5 1.5 Vout (V) Vout (V) 2.0 1.5 Vin=1.0V Vin=1.2V Vin=1.5V Vin=2.0V 1.0 0.5 0.0 0 0.2 www.belling.com.cn 0.4 0.6 Iout (A) 0.8 1.0 0.5 Vin=1.0V Vin=1.2V Vin=1.5V 0.0 1 3 0 0.1 0.2 0.3 0.4 Iout (A) 0.5 0.6 BL8536 Iq vs. Temperature 30 Output Voltage vs. Temperature 3.5 Supply current at Vin Quiescent Current at Vout 25 3.4 15 Vout(V) Iq(uA) 20 10 3.3 3.2 5 3.1 0 Vin=1.0V Vin=2.6V 3.0 -5 -50 0 Temperature(℃) 50 100 -40 0 40 Temperature(℃) 80 120 BLOCK DIAGRAM DETAILED DESCRIPTION BL8536 is a low input voltage start up, current mode DC-DC step up converter. It’s operation can be best understood by referring to the block diagram. Upon starting up, the low voltage startup circuitry drives SW with on-off cycles, transferring energy from input to OUT by storing energy in the inductor during on-time and releasing it to the output during off-time. When OUT reaches 2V, the startup circuit turns off and the main controller takes over. The main control loop consists of a reference, a GM error amplifier, a PWM controller, a current sense amplifier, an oscillator, a PWM logic control, and it is power stage including its driver. The main control loop is a classic current mode www.belling.com.cn 4 control loop. The GM stage integrates the error between FB and REF, and its output is used to compare with a triangular wave which the summing result of the current sense amplifier output and a slope compensation voltage. The output of the comparator is used to drive the power stage to reach regulation. APPLICATION INFORMATION Inductor selection With switching frequency up to 1MHz, small surface mount inductors can be used with values from 2.2uH to 4.7uH. For a given chosen inductor value and application conditions make sure the peak BL8536 inductor current does not exceed the maximum current rating of the selected vendor's inductor. Input and output capacitor selection The BL8536's bootstrap architecture allows the use of very small input capacitor. For applications that only need to drive small output load current, the input capacitor is optional, because once output is started up, the IC's is powered by OUT, a quiet power supply. The output capacitor is used to stabilize the loop and provide ac current to the load. A low ESR ceramic cap with values from 2.2uF to 22uF can be used. Smaller value capacitors are generally cheaper with small footprints, while larger capacitor provides lower ripples and better transient load responses. Also, when extreme low startup voltage is needed, larger output capacitors are needed for the part to startup under heavy load condition. PACKAGE OUTLINE Package SOT-23-3 Devices per reel Package dimension： www.belling.com.cn 5 3000Pcs Unit mm BL8536 Package SOT23-5 Devices per reel 3000 Unit mm SOT-89-3 Devices per reel 1000Pcs Unit mm Package specification： Package Package dimension： www.belling.com.cn 6