Preliminary Datasheet. Features. General Description. Applications. Dual 1.1MHz, 800mA Synchronous DC-DC Buck Converter

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1 General Description The contains two independent 1.1MHz fixed frequency, current mode, PWM synchronous buck (step-down) DC-DC converters, each of them is capable of driving a 800mA load with high efficiency, excellent line and load regulation. Each converter integrates a main switch and a synchronous switch without an external Schottky diode. It is ideal for powering portable equipment that runs from a single Li-ion battery. A standard series of inductors are available from several different manufacturers optimized for use with the. This feature greatly simplifies the design of switch-mode power supplies. This IC is available in DFN package. Features High Efficiency: up to 95% Output Current on Each Channel: 800mA Input Voltage Range: 2.5V to 5.5V Fixed 1.1MHz Frequency 100% Duty Cycle in Dropout Built-in Short Circuit Protection Built-in Thermal Shutdown Function Built-in Current Limit Function Shutdown Current: <1µA Applications GPS WiFi Card Portable Media Player Digital Still and Video Cameras DFN Figure 1. Package Type of 1

2 Pin Configuration DN Package (DFN ) Pin 1 Mark Figure 2. Pin Configuration of (Top View) Pin Description Pin Number Pin Name Function 1 EN1 Channel 1 enable control input. Drive EN1 above 1.5V to turn on the Channel 1. Drive EN1 below 0.6V to turn it off (shutdown current < 0.1µA) 2 FB1 Channel 1 feedback input. Connect FB1 to the center point of the external resistor divider. The feedback voltage is 0.6V 3 VIN2 Channel 2 supply input. Bypass to GND with a 10µF or greater ceramic capacitor 4 GND2 Ground 2 5 SW2 Channel 2 power switch output. Inductor connection to drains of the internal PFET and NFET switches 6 EN2 Channel 2 Enable Control Input. Drive EN2 above 1.5V to turn on the Channel 2. Drive EN2 below 0.6V to turn it off (shutdown current < 0.1µA) 7 FB2 Channel 2 feedback input. Connect FB2 to the center point of the external resistor divider. The feedback voltage is 0.6V 8 VIN1 Channel 1 supply input. Bypass to GND with a 10µF or greater ceramic capacitor 9 GND1 Ground 1 10 SW1 Channel 1 power switch output. Inductor connection to drains of the internal PFET and NFET switches 2

3 Functional Block Diagram EN1, EN2 VIN1, VIN2 1, 6 8, 3 Shutdown Control Slope Compensation Current Limit Detector Current Sense Oscillator PWM Comparator Control Logic Driver 10,5 SW1, SW2 FB1, FB2 V REF with Soft-start 2, 7 0.6V Error Amplifier Over Temperature Detector 9, 4 GND1, GND2 Figure 3. Functional Block Diagram of (Diagram represents ½ of the ) Ordering Information - Circuit Type Package DN: DFN G1: Green TR: Tape & Reel Package Temperature Range Part Number Marking ID Packing Type DFN to 85 ºC DNTR-G1 BDC Tape & Reel BCD Semiconductor's Pb-free products, as designated with "G1" suffix in the part number, are RoHS compliant and green. 3

4 Absolute Maximum Ratings (Note 1) Parameter Symbol Value Unit Input Voltage 1, to 6 V Feedback Voltage V FB1, V FB2-0.3 to +0.3 V EN1, EN2 Pin Voltage V EN1, to +0.3 V SW1, SW2 Pin Voltage V SW1, V SW2-0.3 to +0.3 V Thermal Resistance θ JA 50 ºC/W Operating Junction Temperature T J 150 ºC Storage Temperature T STG -65 to 150 ºC Lead Temperature (Soldering, 10sec) T LEAD 260 ºC Note 1: Stresses greater than those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated under Recommended Operating Conditions is not implied. Exposure to Absolute Maximum Ratings for extended periods may affect device reliability. Recommended Operating Conditions Parameter Symbol Min Max Unit Input Voltage 1, V Maximum Output Current I OUT1 (MAX), I OUT2 (MAX) 800 ma Operating Ambient Temperature T A ºC 4

5 Electrical Characteristics 1 =2 =V EN1 =V EN2 =3.6V, T A =25, unless otherwise specified. Specifications with boldface type apply over full operating temperature range from -40 to 85ºC. Parameters Symbol Conditions Min Typ Max Unit Supply Current on Each Converter I CC V FB =0.55V µa Shutdown Supply Current on Each Converter I SHDN V EN =0V, =5.5V µa Under Voltage Lockout Threshold V UVLO Rising Edge 2.27 V Under Voltage Lockout Hysteresis V HUVLO 200 mv Feedback Bias Current I FB V FB =0.65V na Feedback Voltage V FB I OUT =100mA Maximum Output Current I OUT (MAX) =2.5V, V OUT =0.9V =3.6V, V OUT =1.2V =4.6V, V OUT =3.3V 0.588/ / Switch Current Limit I LIM V FB =0.55V A Oscillator Frequency f OSC MHz V ma EN Pin Threshold V ENL 0.6 V ENH 1.5 V EN Pin Input Leakage Current Internal PFET On Resistance Internal NFET On Resistance I H V EN =3.6V µa I L V EN =0V µa R DSONP I SW =100mA 0.44 Ω R DSONN I SW =-100mA 0.29 Ω Maximum Duty Cycle D MAX V FB =0.55V 100 % Soft-start Time Thermal Shutdown Threshold Thermal Shutdown Hysteresis T SS V EN =0V to I OUT =50mA 220 µs T OTSD 160 ºC T HYS 30 ºC 5

6 Typical Performance Characteristics L1=L2=10µH, C IN1 =C IN2 =C OUT1 =C OUT2 =10µF, T A =25 ºC, unless otherwise noted Frequency (MHz) =3.6V =1.8V I OUT =0A Supply Current (ma) =3.6V V FB =0.55V Input Voltage (V) Temperature ( o C) Figure 4. Frequency vs. Input Voltage Figure 5. Supply Current vs. Temperature Current Limit (A) Output Voltage (V) =3.6V V FB =0.55V =3.6V =1.8V Temperature ( O C) Output Current (A) Figure 6. Current Limit vs. Temperature Figure 7. Output Voltage vs. Output Current 6

7 Typical Performance Characteristics (Continued) L1=L2=10µH, C IN1 =C IN2 =C OUT1 =C OUT2 =10µF, T A =25 ºC, unless otherwise noted Normalized Feedback Voltage (%) =3.6V =1.8V Efficiency (%) =4.2V =1.8V V OUT2 =1.2V Temperature ( o C) Output Current (ma) Figure 8. Normalized Feedback Voltage vs. Temperature Figure 9. Efficiency vs. Output Current I OUT1 500mA 200mV I OUT2 500mA V OUT2 200mV V SW1 5V 20mV V SW2 5V V OUT2 20mV Time 200µs/div Time 1µs/div Figure 10. Load Transient ( =4.2V, =1.8V, V OUT2 =1.2V, I OUT1 =400mA to 800mA, I OUT2 =400 to 800mA) Figure 11. Heavy Load Operation ( =4.2V, =1.8V, V OUT2 =1.2V, I OUT1 =I OUT2 =800mA) 7

8 Typical Performance Characteristics (Continued) L1=L2=10µH, C IN1 =C IN2 =C OUT1 =C OUT2 =10µF, T A =25 ºC, unless otherwise noted. V EN 2V 1V V OUT2 1V Time 400µs/div Figure 12. Start-up from Shutdown ( =4.2V, =1.8V, V OUT2 =1.2V, V EN =0 to 3.6V, I OUT1 =I OUT2 =400mA) 8

9 Typical Application Figure 13. Typical Application of 9

10 Mechanical Dimensions DFN Unit:mm(inch) 10

11 IMPORTANT NOTICE reserves the right to make changes without further notice to any products or specifications herein. does not assume any responsibility for use of any its products for any particular purpose, nor does assume any liability arising out of the application or use of any its products or circuits. does not convey any license under its patent rights or other rights nor the rights of others. MAIN SITE BCD - Headquarters Semiconductor Manufacturing Limited - Wafer BCD FabSemiconductor Manufacturing Limited BCD - Wafer Semiconductor Fab Manufacturing Limited Shanghai - IC Design SIM-BCD Group Semiconductor Manufacturing Co., Ltd. No. Shanghai 1600, Zi SIM-BCD Xing Road, Semiconductor Shanghai ZiZhu Manufacturing Science-based Limited Industrial Park, , China 800 Yi Advanced Shan Road, Analog Shanghai Circuits , (Shanghai) China Corporation Tel: 800, , Yi Shan Road, Shanghai Fax: , China Tel: F, Zone B, 900, 1491, Yi Fax: Shan Road, Shanghai , China Tel: , Fax: Tel: , Fax: REGIONAL SALES OFFICE REGIONAL Shenzhen OfficeSALES OFFICE Shenzhen Shanghai SIM-BCD Office Semiconductor Manufacturing Co., Ltd., Shenzhen Office Shanghai Unit A Room SIM-BCD 1203, Skyworth Semiconductor Bldg., Gaoxin Manufacturing Ave.1.S., Nanshan Co., Ltd. District, Shenzhen Shenzhen, Office Advanced China Analog Circuits (Shanghai) Corporation Shenzhen Office Taiwan Office BCD Taiwan Semiconductor Office (Taiwan) Company Limited 4F, 298-1, BCD Rui Semiconductor Guang Road, (Taiwan) Nei-Hu District, Company Taipei, Limited Taiwan 4F, 298-1, Rui Guang Road, Nei-Hu District, Taipei, USA Office USA BCD Office Semiconductor Corp. BCD Semiconductor Huntwood Ave. Corporation Hayward, CA 94544, Huntwood USA Ave. Hayward, Room Tel: E, 5F, Noble 7951 Center, No.1006, 3rd Fuzhong Road, Futian District, Shenzhen , China Tel: Taiwan 2808 CA Tel : 94544, U.S.A Tel: Fax: Fax: Fax: Tel: Fax: Tel Fax: : Fax: