FP6737 FITIPOWER | Alldatasheet

Document overview

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  • PDF pages: 12

Technical content

Features

  • Inherently Matched LED Current
  • High Efficiency: 87%
  • Drives up to Seven LEDs from a 3.2V Supply
  • 33V Internal Switch
  • Fast 1.2MHz Switching Frequency
  • Use Tiny 1mm Tall Inductors
  • Need only 0.22µF Output Capacitor
  • Low Profile SOT-23-6 and TSOT-23-6 Packages
  • Built-In Open Circuit Protection
  • Over Voltage Protection
  • RoHS Compliant

Applications

  • Cellular Phone
  • Digital Camera
  • MP3 Player
  • GPS Receiver
  • PDA, Handheld Computer TR: Tape / Reel Blank: Tube P: Green G: Green FP6737□□□□ Package Type S6: SOT-23-6 S9: TSOT-23-6 FB Voltage Blank: 250mV A: 104mV

fitipower integrated technology lnc. Figure 2. Typical Application Circuit of FP6737/A SW Switch Pin. Connect inductor/diode here. Minimize trace area at this node to reduce EMI. GND Ground Pin. Connect to local ground plane directly. OVP Over-Voltage Protection Sensing Input Pin. The function will be triggered when the trip point reaches 28V. Leave it unconnected to disable this function. VIN Input Supply Pin. Must be locally bypassed.

fitipower integrated technology lnc. Figure 3. Block Diagram of FP6737/A Note 1： tresses beyond those listed under “Absolute Maximum Ratings" may cause permanent damage to the device.

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Electrical Characteristics

(VIN=3V, =3V, TA=25º C, unless otherwise specified) Parameter Symbol Conditions Min Typ Max Unit Input Voltage Range VIN 2.5 5.5 V Supply Current IIN Switching 0.7 1.5 mA Non switching 50 100 μA =0V 0.1 1 ERROR AMPLIFIER Feedback Voltage VFB FP6737 237 250 263 mV FP6737A 94 104 114 FB Input Bias Current IFB VFB=250mV 1 nA OSCILLATOR Switching Frequency fOSC 0.9 1.2 1.5 MHz Maximum Duty Cycle D 85 90 % POWER SWITCH Switch Current Limit (Note 2) ILIM 350 mA Switch On Resistance RDS(ON) 1 5  Switch Leakage Current ISW(OFF) VSW=33V 0.1 1 μA CONTROL INPUT Voltage High VIH ON 1.5 V Voltage Low VIL OFF 0.4 V OVER VOLTAGE PROTECTION OVP Input Resistance (Note 2) ROVP 1.2 M OVP Threshold VOVP 1V Hysteresis typical 25 28 31 V Note 2：Guarantee by design.

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Application Information

A 10μ inductor is recommended for most FP6737/A applications. Although small size and high efficiency are major concerns, the inductor should have low core losses at 1.2MHz and low DCR (copper wire resistance). Capacitor Selection The small size of ceramic capacitors makes them ideal for FP6737/A applications. X5R a nd X7R types are recommended because they retain their capacitance over wider voltage and temperature ranges better than other types such as Y5V or Z5U. A 1μF input capacitor and a 0.47μF output capacitor are sufficient for most FP6737/A applications. Diode Selection The Schottky diodes, with their low forward voltage drop and fast reverse recovery, are the ideal choices for FP6737/A applications. The forward voltage drop of a Schottky diode represents the conduction losses in the diode while the diode capacitance (CT or C D) represents the switching losses. For diode selection, both forward voltage drop and diode capacitance need to be considered. Schottky diodes with higher current ratings usually have lower forward voltage drop and larger diode capa citance, which can cause significant switching losses at the 1MHz switching frequency of the FP6737/A. A Schottky diode rated at 100mA to 400mA is sufficient for most FP6737/A applications. LED Current Control The LED current is controlled by the feedback resistor (R1 in Figure 20). The FP6737 feedback reference is 250mV and the FP6737A feedback reference is 104mV. The LED current is VFB/R1. In order to have accurate LED current, precision resistors are preferred (1% is recommend ed). The formula and table for R1 selection are shown as below. Version Feedback Reference Voltage VFB(V) LED Current Setting ILED(A) FP6737 0.25 0.25/R1 FP6737A 0.104 0.104/R1 Table 1. R1 Resistor Value Selection Figure 20. LED Driver with Open-Circuit Protection voltage, PWM signal or a filtered PWM signal. FP6737/A is turned on or off by the PWM signal. The LEDs operate at either zero or full current.

10 FP6737/A-1.6-DEC-2011 FP6737/A 85T fitipower integrated technology lnc. Demo Board Circuit & Layout Top Side (SOT-23-6 Package) Bottom Side (SOT-23-6 Package) Component Placement(SOT-23-6 Package) R5 0 LED2 LED1 1uF LED3 LED4 LED5 1uF LED6 LED7 18K 6.34 ohm FB3 OVP 5 SW1 GND2 VIN 6 EN 4 U1 FP6737 1uF L1 10uH VINVOUT 10 ohm 1 122 Enable 0.22uF 0.22uF FP6737/A

11 FP6737/A-1.6-DEC-2011 FP6737/A 85T fitipower integrated technology lnc. Outline Information SYMBOLS UNIT DIMENSION IN MILLIMETER MIN MAX A 0.90 1.45 A1 0.00 0.15 A2 0.90 1.30 B 0.30 0.50 D 2.80 3.00 E 2.60 3.00 E1 1.50 1.70 e 0.90 1.00 e1 1.80 2.00 L 0.30 0.60 Note：Followed From JEDEC MO-178-C. Carrier dimensions

12 FP6737/A-1.6-DEC-2011 FP6737/A 85T fitipower integrated technology lnc. Outline Information (Continued) SYMBOLS UNIT DIMENSION IN MILLIMETER MIN MAX A 0.70 1.10 A1 0.00 0.10 A2 0.70 1.00 B 0.30 0.50 D 2.80 3.00 E 2.60 3.00 E1 1.50 1.70 e 0.90 1.00 e1 1.80 2.00 L 0.30 0.60 Carrier dimensions Life Support Policy Fitipower’s products are not authorized for use as critical components in life support devices or other medical systems.