Catalyst Semiconductor CAT3647, CAT3648 LED drivers provide 32-level LCD backlight programming in 3% step increments

Catalyst Semiconductor, a supplier of analogue, mixed-signal and non-volatile memory semiconductors, has expanded its line of patented, Quad-Mode fractional charge pump LED drivers.

Two new high-resolution brightness devices feature 32-dimming levels to provide enhanced LCD backlight control in emerging portable product applications.

According to Catalyst, the new CAT3647 and CAT3648 address the need for high-resolution LCD control and longer battery life in cell phones, digital cameras and other handheld devices, where designers need to balance higher performance features with longer battery life.

They give designers control of LED current and brightness with the ability to program in step increments as small as three percent, to help produce a richer user experience. This is achieved via Catalyst's 1-wire EZDim programming interface, which supports 32 linear steps from full-scale brightness down to zero current.

The new LED drivers are four-mode fractional charge pumps (1x, 1.33x, 1.5x, 2x), providing 10 percent higher efficiency and no added cost, compared to three-mode charge pumps. The CAT3647 drives three LEDs at 30mA each and the CAT3648 drives four LEDs at 25mA each, both with power efficiency as high as 92 percent. Both devices save significant board space and costs since they come in a low profile, 3mm x 3mm, 16-pad TQFN package and do not require additional capacitors, as do existing four-mode LED drivers.

The CAT3647 and CAT3648 join the following devices in Catalyst's Quad-Mode family of LED drivers:
the CAT3604V four-channel LED driver with PWM dimming interface; the CAT3636 six-channel (1-wire EZDim interface with 32 dimming levels); the CAT3644 four-channel and CAT3643 three-channel devices (1-wire EZDim interface with six dimming levels); and the CAT3637 six-channel (1-wire EZDim interface with 16 dimming levels).

Product Features

• Patented Quad-Mode™ high-efficiency charge pump switching architecture
• 32-level, high-resolution dimming via 1-Wire EZDim™ interface
• Fourth charge pump mode achieves 1.33x boost mode with only 2 flying capacitors
• Power efficiency up to 92 percent
• CAT3647 drives up to 3 LEDs at 30mA each, in 32 linear steps, CAT3648 drives up to 4 LEDs at 25mA each, in 32 linear steps
• Fully protected
• Packaging: 16-pad TQFN, 3mm x 3mm

Price and Availability

Pricing for the CAT3647 LED driver is $0.64 each, in 10.000 piece quantities. The CAT3648 is priced at $0.68 each in 10,000 piece quantities. Samples and evaluation kits are available now. Projected lead-time for production quantities is currently 6 to 8 weeks ARO.

See http://www.catsemi.com.