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| Preliminary Specification TM CR-F33T PFM STEP-UP DC/DC CONVERTER GENERAL DESCRIPTION The CR-F33T is a PFM step-up DC/DC converter IC and has a high efficiency. These devices consist of a bandgap, a comparator, an oscillator, a driver, and a high current output switch. The CR-F33T provides a higher fixed voltage from the smaller input voltage. The CR-F33T is used for single- or dual-cell battery operation. FEATURES BLOCK DIAGRAM VDD Bandgap LX Digital Control FB Clock Select VSSA EN 150KHz OSC VSS PIN CONFIGURATION Low Voltage Operation Possible Low Supply Current Small Number of External Components Internal Power Switch APPLICATIONS Battery-Powered Instruments Hand-Held Instruments Hand-Held Communication Instruments Cameras SOP-8 (Top View) VDD 1 FB 2 EN 3 NC 4 8 LX 7 VSSA 6 VSS 5 NC SOT-89-3 (Top View) 1 3 2 VSS VDD LX ORDERING INFORMATION CR-FXXX Step-up Package P: SOP-8 T: SOT-89-3 Output Voltage 33 : 3.3V 1 Preliminary Specification TM CR-F33T PFM STEP-UP DC/DC CONVERTER PIN DESCRIPTION Pin No. 1 2 3 4 5 6 7 8 Pin Name VDD FB EN NC NC VSS VSSA LX Pin Function Output voltage pin and also power supply pin for the device The pin of feedback voltage Chip enable pin No internal connection to this pin No internal connection to this pin Ground pin Ground pin Switch pin, connected to inductor/diode STEP-UP CONVERTER APPLICATION 1N5819 220uH 1N5819 220uH VDD EN VDD FB 100uF CR-F33-P VSSA VIN 100uF LX CR-F33-T LX VIN Absolute Maximum Ratings Supply Voltage-------------------------------------------------------------- - 0.3V to 7V Input Voltage---------------------------------------------------------------- - 0.3V to VDD+0.3 Operating Temperature Range--------------------------------------------- 0 o C to 50 o C Storage Temperature Range----------------------------------------------- - 40 o C to 150 o C VSS VSS 2 Preliminary Specification TM CR-F33T PFM STEP-UP DC/DC CONVERTER Electrical Characteristics Parameter Start-Up Voltage Holding Voltage Input Voltage Output Voltage No-Load Input Current Standby Current Input Low Voltage Input High Voltage Oscillator Frequency Efficiency Symbol VST VHold VIN VDD IIN ISB VIL VIH Fosc b Test Conditions Iload = 1mA Iload = 1mA No Load Min. 0.45 1 3 Typ. Max. Units 0.9 1 V V 3.5 3.3 8 3.6 14 2 V V g A g A V V KHz % No Load VEN = 0 Enable/Disable Pin Enable/Disable Pin 0 1 0.4 VDD 150 VIN = 1.5V, Iload = 10mA 83 OPERATION OF STEP-UP CONVERTER A step-up converter diagram is illustrated below. In the diagram, the converter can generate a fixed, higher voltage from a lower one. When SW stays ON, IL1 flows through L, and the converter converts the electric energy into the magnetic one and stores it in L, in which Imax is proportional to ton; when SW lies OFF, Shottky diode is forced to be ON, while the energy stored in inductor L be discharged into capacitor, thereby charging the output voltage to a value expected. IL IL2 L + IL1 VIN -SW CL Vout -ILmin ton T=1/fosc toff t D Iout + ILmax 3 Preliminary Specification TM CR-F33T PFM STEP-UP DC/DC CONVERTER TYPICAL PERFORMANCE CHARACTERISTICS L=47uH; C=100uF 90 Vin=3V 80 70 Vin=1.2V 60 Efficiency (% ) 50 40 30 20 10 0 0 10 20 30 40 50 Iload (mA) 60 70 80 90 100 Vin=1.5V Vin=2V 4 Vin=3V Vin=2.5V 3 Vin=1.2V E fficiency (% ) Vin=1.5V Vin=2.5V Vin=2V 2 1 0 0 10 20 30 40 50 Iload (mA) 60 70 80 90 100 L=100uH; C=100uF 90 80 70 60 Efficiency (%) 50 40 30 20 10 0 0 10 20 30 40 50 Iload (mA) 60 70 80 90 100 Vin=1.5v 4 Vin=3V Vin=1.2V Vin=2V Vin=2.5V Vin=3V 3 Vin=1.5V Vin=1.2V Efficiency (%) Vin=2.5V Vin=2V 2 1 0 0 10 20 30 40 50 Iload (mA) 60 70 80 90 100 4 Preliminary Specification TM CR-F33T PFM STEP-UP DC/DC CONVERTER L=150uH; C=100uF 100 90 Vin=3V 4 80 70 Efficiency (%) 60 Vin=1.5V 50 40 30 1 Vin=1.2V 3 Vin=3V Efficiency (%) Vin=1.2V Vin=1.5V Vin=2V Vin=2.5V Vin=2V Vin=2.5V 2 20 10 0 0 10 20 30 40 50 Iload(mA) 60 70 80 90 100 0 0 10 20 30 40 50 Iload (mA) 60 70 80 90 100 L=220uH; C=100uF 90 80 4 Vin=3V 70 60 E fficiency (% ) Vin=1.5V 50 40 30 20 10 0 0 10 20 30 40 50 Iload (mA) 60 70 80 90 100 Vin=2V Vin=3V Vin=1.2V 3 Vin=1.5V Vin=2.5V Vin=2V Vin=1.2V E fficiency (% ) Vin=2.5V 2 1 0 0 10 20 30 40 50 Iload (mA) 60 70 80 90 100 5 Preliminary Specification TM CR-F33T PFM STEP-UP DC/DC CONVERTER LX Pin Waveform & VDD LX Pin Waveform & VDD VDD Vin=1.2V@Iload=15mA LX 5us/Div LX Pin Waveform & VDD VDD Vin=2V@Iload=15mA LX 5us/Div LX Pin Waveform & VDD VDD Vin=3V@Iload=15mA LX 5us/Div VDD Vin=1.5V@Iload=15mA LX 5us/Div LX Pin Waveform & VDD VDD Vin=2.5V@Iload=15mA LX 5us/Div 6 Preliminary Specification TM CR-F33T PFM STEP-UP DC/DC CONVERTER The magnitude of inductor will influence the performance of DC/DC converter. The following table guides users to select the suitable magnitude of inductor for single- or dual-cell battery operation when the output terminal connects to different current load. Consequently, users can obtain a cell battery with longer life. Current Load (mA) Iload < 10 10 < Iload < 20 20 < Iload < 30 30 < Iload < 40 40 < Iload < 50 50 < Iload < 60 70 < Iload < 80 80 < Iload < 90 90 < Iload < 100 1-cell battery 220uH 150uH 47uH 47uH 47uH / / / / 2-cell battery 220uH 220uH 220uH 150uH 150uH 100uH 47uH 47uH 47uH 7 Preliminary Specification TM CR-F33T PFM STEP-UP DC/DC CONVERTER PACKAGE INFORMATION 8 Preliminary Specification TM CR-F33T PFM STEP-UP DC/DC CONVERTER 9 1N5819 220uH VDD EN FB 100uF CR-F33-P VSSA VIN LX VSS |
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