MAX1579ETG+

Price range: $4.48 - $5.09

The MAX1578/MAX1579 provide four regulated outputsto meet all the voltage requirements for small activematrixTFT-LCD displays in handheld devices whereminimum external components and high efficiency arerequired. Each device consists of three advancedcharge pumps for LCD bias power and a step-up converterfor driving up to 8 series white LEDs for backlighting.The input voltage range is from 2.7V to 5.5V.The charge pumps provide fixed +5V, +15V, and -10Vfor the LCD bias circuits. No external diodes are needed.A high-efficiency, fractional (1.5x/2x) charge pumpfollowed by a low-dropout linear regulator provides +5Vto power the source driver. Automatic mode changingachieves the highest conversion efficiency. Two multistage,high-voltage charge pumps generate +15V and-10V to provide VON and VOFF, respectively. Utilizing aunique clocking scheme and internal drivers, thesecharge pumps eliminate parasitic charge-current glitchesand reduce maximum input current, resulting in lowelectromagnetic emissions. The outputs are sequencedduring startup and shutdown. In shutdown, the outputsare discharged to zero.The high-efficiency inductor step-up converter drivesup to 8 white LEDs in series with a constant current toprovide backlighting. The series connection allows theLED currents to be identical for uniform brightness andminimizes the number of traces to the LEDs. TheMAX1578 regulates constant LED current over theentire temperature range. The MAX1579 features a temperaturederating function to avoid overdriving thewhite LEDs during high ambient temperatures, enablinghigher drive current below +42°C.The MAX1578/MAX1579 are available in space-saving24-lead 4mm x 4mm thin QFN packages.ApplicationsInternet AppliancesLCD Displays with White LED BacklightPDAs, PalmtopsSmartphones