No-Noise, Four-Channel White LED Drivers Feature True-load Disconnect in Shutdown
Leadis Technology, Inc. announced the LDS8845 and the LDS8846 family of no-noise, highly-efficient 4-channel white LED drivers. These devices target low-cost handsets and portable products that use lower-VF white LEDs and lower-cost TFT-LCD modules. The family offers part-to-part LED current accuracy better than 7.5 percent and channel-to-channel matching better than 3 percent. Both products offer true-load disconnect in shutdown, output overcurrent protection, thermal shutdown protection, and a 100 kHz-rated LED current control interface for those applications where it is desirable to minimize or eliminate audio band noise injection. Packaged in 0.8 mm × 3 mm × 3 mm 16-lead TQFN packages, the LDS8845 operates from 2.7V to 5.5V. An inexpensive, 15.8 k? resistor sets the LDS8845's full-scale LED output current to 30 mA per channel and allows the system designer to program the full-scale LED current to lower full-scale levels. A two-wire interface is provided to program the 4 LEDs as a single group or individually; in addition, the control interface can accept a pulse-width modulated (PWM) signal to adjust optionally the average LED current through duty cycle control. The LDS8846 is parametrically identical to the LDS8845, offering a third control input, in pin-compatible 0.8 mm × 3 mm × 3 mm and 4 mm × 4 mm 16-lead TQFN packages. The third control input allows the system engineer to configure the LDS8846's LED drivers in one of eight configurations for maximum flexibility.
Leadis Technology, Inc.
408 331-8600, www.leadis.com