白光LED驱动IC LN9300 SN3228B SN3228A

   LN9300是一款用于白光LED驱动的*的低压差电流源，可以作为传统白光LED驱动设计中镇流电阻的替代产品使用。LN9300比镇流电阻更具有优势，体现于：*压差、恒定电流，受电压变化影响小，更小的体积，更高的效率。适合应用于由电池供电直接驱动白光LED的场合。它通过内置电阻来设置四个LED的输出电流，能在2.5v～6v的电压范围内提供稳定的四路20mA电流，相互之间的匹配度*3%，而*需要60mv的跌落电压。

                                       白光LED驱动IC--SN3228

Applications

l   White LED backlighting

l   Mp3, Mp4, PMP

l   Cell phone, *art phone, PDA

 Features

l  UTQFN-12 (2mm × 2mm ) package

l  Low shutdown current: ISHDN <3μA

l  Automatic soft start

l  Built-in thermal protection

l  No inductors, low noise operation

l  Drives up to four (SN3228A)/six (SN3228B) channels of LEDs -14 current levels

l  Fully programmable current with single wire

l  VCC range: 2.8V to 5.5V

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Description

     The SN3228A (SN3228B) is a low noise, constant frequency charge pump DC/DC converter for white LED applications. The SN3228A (SN3228B) is capable of driving up to four (six) channels of LEDs at preset 20mA per channel from a 2.8V to 5.5V input. The current sinks may be operated individually or in parallel for driving higher current LEDs. Only one 1μF *all capacitor (at C thru C-) and two *all 2.2μF capacitors (at VCC and VOUT) are needed, it makes this part ideally suited for *all, battery-powered applications.

      The serial di*al input is used to enable, disable, and set current for each LED with 14 settings down to 1.8mA. Each output of the SN3228A/SN3228B is equipped with built-in soft-start circuitry prevents excessive inrush current during start-up. A low-current shutdown feature disconnects the load from the input and reduces quiescent current to less than 3μA.The SN3228A and SN3228B are available in a Pb-free, space-saving 2mm × 2mm UTQFN-12 package.