Date: 02/08/2011

Independent dimming of 48 LED lights possible with Linear's PWM generator chip

Linear Technology has announced the LT8500, a pulse width modulation (PWM) generator with 48 independent channel which can be used in PWM-intensive applications such as LED control and industrial and robotic applications. For example, the LT8500 can be used with three LT3595As, 16-channel LED drivers, to deliver 48-independently dimmed LED strings for locally dimmed LED backlighting for large LCD displays. The correction resistor allows matching light output of each LED string.

Key features of LT8500 include:
3V to 5.5V Input Voltage
48 Independent PWM Outputs
TTL/CMOS Logic 50MHz Serial Data Interface
12-Bit (4096 Steps) PWM Width Resolution
6-Bit (64 Steps) PWM Correction
(±50% of Programmed PWM Width)
Up to 6.1kHz PWM Frequency
(PWMCK = 25MHz)
Phase-Shift Option Reduces Switching Noise
Directly Controls Three LT3595A
16-Channel LED Drivers
Diagnostic Information: Sync Error/Open LED Flags

Linear Technology says for LED applications, each channel has individual 6-bit dot correction current adjustment and 12-bit gray scale PWM dimming and 40ns on-time provides dynamic contrast ratios. Both correction and gray scale dimming are accessible via a serial interface in TTL/CMOS logic and the flags are sent with additional state information, on the serial data interface during status read back. As per Linear Technology the 50MHz cascadable serial data interface includes buffering and skew balancing, easing the design for PWM-intensive applications such as large screen LCD dynamic backlighting.

Available: Now
Price: $2.95 each for 1Kpiece
Package: 56-lead 5mm x 9mm QFN package

For more information, visit www.linear.com