Preliminary Datasheet Dual 1.1MHz, 800mA Synchronous DC-DC Buck Converter General Description Features The AP3422 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 AP3422. This feature greatly simplifies the design of switch-mode power supplies. AP3422 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 • • • • This IC is available in DFN-3×3-10 package. GPS WiFi Card Portable Media Player Digital Still and Video Cameras DFN-3×3-10 Figure 1. Package Type of AP3422 Sep. 2011 Rev. 1. 1 BCD Semiconductor Manufacturing Limited 1 Preliminary Datasheet Dual 1.1MHz, 800mA Synchronous DC-DC Buck Converter AP3422 Pin Configuration DN Package (DFN-3×3-10) Pin 1 Mark EN1 1 10 SW1 9 GND1 8 VIN1 FB1 2 VIN2 3 GND2 4 7 FB2 SW2 5 6 EN2 Exposed Pad Figure 2. Pin Configuration of AP3422 (Top View) Pin Description Pin Number Pin Name 1 EN1 2 FB1 3 VIN2 4 GND2 5 SW2 6 EN2 7 FB2 8 VIN1 9 GND1 10 SW1 Sep. 2011 Function 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) Channel 1 feedback input. Connect FB1 to the center point of the external resistor divider. The feedback voltage is 0.6V Channel 2 supply input. Bypass to GND with a 10µF or greater ceramic capacitor Ground 2 Channel 2 power switch output. Inductor connection to drains of the internal PFET and NFET switches 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) Channel 2 feedback input. Connect FB2 to the center point of the external resistor divider. The feedback voltage is 0.6V Channel 1 supply input. Bypass to GND with a 10µF or greater ceramic capacitor Ground 1 Channel 1 power switch output. Inductor connection to drains of the internal PFET and NFET switches Rev. 1. 1 BCD Semiconductor Manufacturing Limited 2 Preliminary Datasheet Dual 1.1MHz, 800mA Synchronous DC-DC Buck Converter AP3422 Functional Block Diagram EN1, EN2 VIN1, VIN2 1, 6 8, 3 Shutdown Control Slope Compensation Oscillator VREF with Soft-start FB1, FB2 Current Sense Current Limit Detector PWM Comparator 10,5 Control Logic Driver SW1, SW2 0.6V Error Amplifier Over Temperature Detector 2, 7 9, 4 GND1, GND2 Figure 3. Functional Block Diagram of AP3422 (Diagram represents ½ of the AP3422) Ordering Information AP3422 G1: Green Circuit Type TR: Tape & Reel Package DN: DFN-3×3-10 Package Temperature Range DFN-3×3-10 -40 to 85 ºC Part Number AP3422DNTR-G1 Marking ID BDC Packing Type Tape & Reel BCD Semiconductor's Pb-free products, as designated with "G1" suffix in the part number, are RoHS compliant and green. Sep. 2011 Rev. 1. 1 BCD Semiconductor Manufacturing Limited 3 Preliminary Datasheet Dual 1.1MHz, 800mA Synchronous DC-DC Buck Converter AP3422 Absolute Maximum Ratings (Note 1) Parameter Symbol Value Unit Input Voltage VIN1, VIN2 -0.3 to 6 V Feedback Voltage VFB1, VFB2 -0.3 to VIN +0.3 V EN1, EN2 Pin Voltage VEN1, VIN2 -0.3 to VIN+0.3 V SW1, SW2 Pin Voltage VSW1, VSW2 -0.3 to VIN+0.3 V Thermal Resistance θJA 50 ºC/W Operating Junction Temperature TJ 150 ºC Storage Temperature TSTG -65 to 150 ºC Lead Temperature (Soldering, 10sec) TLEAD 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 VIN1, VIN2 2.5 5.5 V Maximum Output Current IOUT1 (MAX), IOUT2 (MAX) 800 TA -40 Operating Ambient Temperature Sep. 2011 Rev. 1. 1 mA 85 ºC BCD Semiconductor Manufacturing Limited 4 Preliminary Datasheet Dual 1.1MHz, 800mA Synchronous DC-DC Buck Converter AP3422 Electrical Characteristics VIN1=VIN2=VEN1=VEN2=3.6V, TA=25℃, unless otherwise specified. Specifications with boldface type apply over full operating temperature range from -40 to 85ºC. Parameters Symbol Supply Current on Each Converter Shutdown Supply Current on Each Converter Under Voltage Lockout Threshold Under Voltage Lockout Hysteresis Typ Max Unit VFB=0.55V 400 600 μA ISHDN VEN=0V, VIN=5.5V 0.01 1 μA VUVLO Rising Edge 2.27 V 200 mV ICC Conditions VHUVLO Feedback Bias Current IFB VFB=0.65V Feedback Voltage VFB IOUT=100mA Maximum Output Current IOUT (MAX) Switch Current Limit ILIM Oscillator Frequency fOSC Soft-start Time VFB=0.55V 0.5 50 nA 0.588/ 0.582 0.600 0.612/ 0.618 V 800 mA 800 800 0.95 1.25 0.8 1.1 On On A 1.4 0.6 1.5 VENH EN Pin Input Leakage Current Maximum Duty Cycle VIN=2.5V, VOUT=0.9V VIN=3.6V, VOUT=1.2V VIN=4.6V, VOUT=3.3V -50 VENL EN Pin Threshold Internal PFET Resistance Internal NFET Resistance Min MHz V IH VEN=3.6V -0.1 0.1 μA IL VEN=0V -0.1 0.1 μA RDSONP ISW=100mA 0.44 Ω RDSONN ISW=-100mA 0.29 Ω VFB=0.55V 100 % VEN=0V to VIN IOUT＝50mA 220 μs DMAX TSS Thermal Shutdown Threshold TOTSD 160 ºC Thermal Shutdown Hysteresis THYS 30 ºC Sep. 2011 Rev. 1. 1 BCD Semiconductor Manufacturing Limited 5 Preliminary Datasheet Dual 1.1MHz, 800mA Synchronous DC-DC Buck Converter AP3422 Typical Performance Characteristics L1=L2=10μH, CIN1=CIN2=COUT1=COUT2=10μF, TA=25 ºC, unless otherwise noted. 0.7 1.4 0.6 Supply Current (mA) Frequency (MHz) 1.3 1.2 1.1 1.0 0.5 0.4 VIN=3.6V 0.3 VOUT1=1.8V 0.9 VIN=3.6V IOUT=0A 0.8 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 VFB=0.55V 0.2 -60 6.0 -40 -20 0 20 Input Voltage (V) 60 80 100 120 140 160 o Figure 4. Frequency vs. Input Voltage Figure 5. Supply Current vs. Temperature 2.0 2.0 1.8 1.8 1.6 1.6 1.4 Output Voltage (V) Current Limit (A) 40 Temperature ( C) 1.2 1.0 0.8 0.6 1.4 1.2 1.0 0.8 0.6 0.4 VIN=3.6V 0.2 VFB=0.55V 0.0 -60 -40 -20 0 20 40 60 80 VOUT1=1.8V 0.2 0.0 0.0 100 O 0.2 0.4 0.6 0.8 1.0 1.2 1.4 Output Current (A) Temperature ( C) Figure 6. Current Limit vs. Temperature Sep. 2011 VIN=3.6V 0.4 Figure 7. Output Voltage vs. Output Current Rev. 1. 1 BCD Semiconductor Manufacturing Limited 6 Preliminary Datasheet Dual 1.1MHz, 800mA Synchronous DC-DC Buck Converter AP3422 Typical Performance Characteristics (Continued) L1=L2=10μH, CIN1=CIN2=COUT1=COUT2=10μF, TA=25 ºC, unless otherwise noted. 100 1.5 90 1.0 0.5 Efficiency (%) Normalized Feedback Voltage (%) 2.0 0.0 -0.5 -1.0 -2.0 -60 -20 0 20 40 60 80 VOUT2=1.2V 50 100 0 200 400 600 800 Output Current (mA) o Temperature ( C) Figure 8. Normalized Feedback Voltage vs. Temperature IOUT1 500mA VOUT1 200mV Figure 9. Efficiency vs. Output Current VSW1 5V VOUT1 20mV IOUT2 500mA VOUT2 200mV VSW2 5V VOUT2 20mV Time 200μs/div Time Figure 10. Load Transient (VIN=4.2V, VOUT1=1.8V, VOUT2=1.2V, IOUT1=400mA to 800mA, IOUT2=400 to 800mA) Sep. 2011 VOUT1=1.8V 60 VOUT1=1.8V -40 70 VIN=4.2V VIN=3.6V -1.5 80 Rev. 1. 1 1μs/div Figure 11. Heavy Load Operation (VIN=4.2V, VOUT1=1.8V, VOUT2=1.2V, IOUT1=IOUT2=800mA) BCD Semiconductor Manufacturing Limited 7 Preliminary Datasheet Dual 1.1MHz, 800mA Synchronous DC-DC Buck Converter AP3422 Typical Performance Characteristics (Continued) L1=L2=10μH, CIN1=CIN2=COUT1=COUT2=10μF, TA=25 ºC, unless otherwise noted. VEN 2V VOUT1 1V VOUT2 1V Time 400μs/div Figure 12. Start-up from Shutdown (VIN=4.2V, VOUT1=1.8V, VOUT2=1.2V, VEN=0 to 3.6V, IOUT1=IOUT2=400mA) Sep. 2011 Rev. 1. 1 BCD Semiconductor Manufacturing Limited 8 Preliminary Datasheet Dual 1.1MHz, 800mA Synchronous DC-DC Buck Converter AP3422 Typical Application Figure 13. Typical Application of AP3422 Sep. 2011 Rev. 1. 1 BCD Semiconductor Manufacturing Limited 9 Preliminary Datasheet Dual 1.1MHz, 800mA Synchronous DC-DC Buck Converter AP3422 Mechanical Dimensions DFN-3×3-10 Sep. 2011 Rev. 1. 1 Unit:mm(inch) BCD Semiconductor Manufacturing Limited 10 BCD Semiconductor Manufacturing Limited http://www.bcdsemi.com IMPORTANT NOTICE IMPORTANT NOTICE BCD Semiconductor BCD Semiconductor Manufacturing Manufacturing Limited Limited reserves reserves the the right right to to make make changes changes without without further further notice notice to to any any products products or or specifispecifications herein. cations herein. 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