MAX9590

14 Programmable Gamma Reference Buffers with 4 Static References for TFT-LCD Displays

Generates 14 Channels of Programmable Gamma Reference and Four Channels of Static Reference with Peak Current Greater than 200mA and 8-Bit Resolution

Data Sheet (Rev. 1)

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Overview

14 Programmable Reference Voltages

Four Static Reference Voltages

Independent DACs with 8-Bit Resolution

Two Register Banks for Two Sets of Gamma Values

Fast Switching between Gamma Values

16.5V (max) Operating Voltage

Output Swing within 150mV of Rails

Peak Current Greater than 200mA

Output Channels Tri-Stated During Wake-Up

The MAX9590 provides 14 programmable voltage references and four static voltage references for gamma correction in TFT-LCD displays. Two register banks are provided to store two sets of gamma reference values. Gamma values are programmed into the banks through the I²C interface and the outputs can switch between values in 0.5µs.

The 14 programmable reference voltages are divided evenly into seven upper and seven lower voltages for the upper and lower gamma curves of LCD column drivers.

Each gamma reference voltage has an 8-bit digital-to-analog converter (DAC) and isolation buffer associated with it to ensure stable operation. Therefore, the reference voltages remain stable without synchronizing to the LCD horizontal timing. In addition, each buffer is able to provide a high current that further ensures a stable voltage when critical levels and patterns are displayed.

The 14 programmable buffers wake up in the high-impedance state until the registers are programmed. This protects the LCD system from high transient currents during the startup phase.

The MAX9590 is available in a 38-pin TQFN package and is specified for operation over the -40°C to +85°C temperature range.

Applications