BILLERICA, MASS. An electroluminescent (EL) lamp driver optimized for applications that use a 32-kHz clock source is available now from Sipex Corp.
Jack Olson, manager of the analog display product line, said the SP4414 is Sipex's smallest and lowest-cost EL lamp driver. Available in 8-pin SOIC and micro-SOIC packages, it is priced from 78 cents each in quantities of 10,000.
The SP4414 uses an external 32-kHz clock signal instead of an on-chip oscillator to drive control signals for coil and lamp circuitry. It provides high-drive capability for EL lamps up to 4 square inches in size.
Besides reducing die size and product cost, the design provides precision control over coil and lamp frequencies, plus tight performance over temperature extremes.
An external 32-kHz clock simplifies the backlight system design by eliminating the need to select external resistor values and models to set internal oscillator frequencies.
The 32-kHz operation is synchronized with standard clock designs in single-cell applications, which makes the driver suitable for portable devices like PDAs, MP3 players, handheld GPS units, pagers and two-way radios, as well as applications that use LCDs in dim or low-light environments.
Olson described the SP4414 as a high-voltage output dc/ac inverter specifically designed to drive EL lamps to backlight liquid-crystal displays, keypads and readouts used in battery-operated portable equipment.
Operating from a 2.2-volt to 4.5-V battery source, the device features a low-power standby mode that draws less than 100-nanoampere (typical) standby current.
Three additional components are needed for standard operation: an inductor, a capacitor and an optional fast-recovery diode, which reduces board space and minimizes system cost, Sipex said.
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EETInfo No. 603