FAN4855 Fairchild Semiconductor, FAN4855 Datasheet
FAN4855
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FAN4855 Summary of contents
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... Detect Out ©2005 Fairchild Semiconductor Corporation FAN4855 Rev. 1.0.1 General Description The FAN4855 is a low power boost regulator designed for low voltage conversion in 2-cell battery powered systems such as digital cameras, cell phones and PDAs. The converter starts-up at 1.3V and operates after the start at an input voltage as low as 1V. Output voltage can be adjusted by external resistors from 3 ...
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... Switch Voltage (V to GND) L Voltage on any other Pin Peak Switch Current (Ipeak) Output Current (I ) OUT Continuous Power Dissipation Thermal Resistance (θ Junction Temperature Storage Temperature Range Lead Temperature (soldering, 10s) FAN4855 Rev. 1.0.1 8-Pin TSSOP SHDN 2 7 LBI 3 6 LB0 4 5 ...
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... Quiescent Current LBO Output Voltage Low SHDN Input Threshold Voltage SHDN Input Threshold Voltage Notes: 1. R4, R5, R6 tolerance ≤ 0.1%. 2. Current through R1 not taken into account. FAN4855 Rev. 1.0.1 Min. -40 1.6 3.0 = 1mA -40°C to +85°C. Test Circuit Fig.1. Typical values are at LOAD ...
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... VIN 2 1 1.6V to 3.0V R1 750K SHDN 2 1 Reset 47µF R2 240K Ext Pull GND 2 1 FAN4855 Rev. 1.0.1 10uH U1 FAN4855 JP2 1 8 Vin Gnd 2 7 SHDN VL JP3 3 6 LBI Vout 4 5 LBO FB R3 100K R6 287K Figure 1. Test Circuit 4 J1 SCOPE JACK ...
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... Efficiency vs. Load Current Vout = 5V 100.0 Vin=3V 90.0 80.0 Vin=2.0V Vin=1.5V 70.0 60.0 50.0 40.0 30.0 20.0 10.0 0.0 0 Output Current, mA Starting Up and Turning Off V = 3.3V, Iloads = 10mA to 50mA OUT 4 3.5 3 TURN OFF: Iload=50mA 2.5 Iload=10mA 2 1.5 1 0.5 0 0.6 0.8 1.0 1.2 Input Voltage, V FAN4855 Rev. 1.0 10µ 47µ 100.0 90.0 80.0 70.0 60 OUT 50.0 40.0 30.0 20.0 10.0 0.0 0.1 3 3.5 4 2.3 2.1 1.9 1.7 1.5 1.3 1.1 0.9 0.7 0.5 100 1000 1 START ...
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... Typical Operating Characteristics No Load Supply Current vs. Input Voltage 1000 “ON” OUT 100 V = 3.3V OUT 10 “OFF” Input Voltage (V) FAN4855 Rev. 1.0 10µ 47µ 0.2 0 -0.2 -0 47µF/1.0µ 25°C) OUT Output Voltage vs. Temperature - Temperature (° ...
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... Typical Operating Characteristics Line Transient Response @100mA Load Load Transient Response Heavy-Load Switching Waveforms FAN4855 Rev. 1.0.1 (Continued) Inductor Current and Switching Node Voltage OUT 7 Exiting Shutdown V OUT V SHDN Load Transient Response Inductor Current V L www.fairchildsemi.com ...
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... SHDN LIMIT Functional Description Boost Regulator FAN4855 is an adjustable boost regulator that combines variable ON and minimum OFF architecture with syn- chronous rectification. Unique control circuitry provides high-efficiency power conversion for both light and heavy loads by transitioning between discontinuous and contin- uous conduction mode based on load conditions. There is no oscillator ...
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... Inductor Selection The inductor parameters directly influencing the device performance are the saturation current and the DC resis- tance. The FAN4855 operates with a typical inductance of 10µH. The lower the resistance, the higher the effi- ciency. The saturation current should be rated higher than 0 ...
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... PCB recommended practice. FAN4855 Rev. 1.0.1 Application Example The FAN4855 can be used as a constant current source to drive white LEDs like QTLP670C-IW. As shown in the diagram below, the current is maintained constant over a wide range of input voltages. ...
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... Mechanical Dimensions Package: T08, 8-Pin TSSOP 0.113 - 0.123 (2.87 - 3.12) 8 PIN 0.026 BSC (0.65 BSC) 0.008 - 0.012 0.033 - 0.037 (0.20 - 0.30) (0.84 - 0.94) FAN4855 Rev. 1.0.1 0.169 - 0.177 0.246 - 0.258 (4.29 - 4.50) (6.25 - 6.55) 0.043 MAX (1.10 MAX) 0°-8° 0.020 - 0.028 0.002 - 0.006 (0.51 - 0.71) (0.05 - 0.71) SEATING PLANE 11 0.004 - 0.008 (0.10 - 0.20) www.fairchildsemi.com ...
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... PRODUCT STATUS DEFINITIONS Definition of Terms Datasheet Identification Advance Information Preliminary No Identification Needed Obsolete FAN4855 Rev. 1.0.1 PowerSaver™ ISOPLANAR™ PowerTrench LittleFET™ QFET MICROCOUPLER™ QS™ MicroFET™ MicroPak™ ...