MAX9668

The MAX9668 outputs eight voltage references for gamma correction in TFT LCDs and one voltage reference for VCOM. Each gamma reference voltage has its own 10-bit digital-to-analog converter (DAC) and buffer to ensure a stable voltage. The VCOM reference voltage has its own 10-bit DAC and an amplifier to ensure a stable voltage when critical levels and patterns are displayed. The MAX9668 features integrated multiple-time programmable (MTP) memory to store gamma and VCOM values on the chip, eliminating the need for external EEPROM. The MAX9668 supports up to 100 write operations to the on-chip nonvolatile memory.

The gamma outputs can drive 200mA peak transient current and settle within 1µs. The VCOM output can provide 600mA peak transient current and also settles within 1µs. The analog supply voltage range extends from 9V to 20V, and the digital supply voltage range extends from 2.7V to 3.6V.

Gamma values and the VCOM value are programmed into registers through the I²C interface.

Applications

• TFT LCDs