ADD8707

12-Channel Gamma Buffers with VCOM and Regulator ADD8707 FEATURES 12 precision gamma reference outputs Mask-programmable gamma resistors: 0.2% resolution and 0.1% accuracy Mask programmable voltage regulator: 0.4% accuracy Upper 6 buffers swing to VDD Lower 6 buffers swing to GND Single-supply operation: 7.5 V to 16 V Gamma current drive: 15 mA per channel VCOM peak output current: 250 mA Outputs stable under load conditions 48-lead, Pb-free LFCSP package FUNCTIONAL BLOCK DIAGRAM VREG OUT MASK-PROGRAMMABLE REGULATOR RESISTORS FB 700Ω* VCOM GND + – GAMMA BUFFERS VOUT12 700Ω* 700Ω* MASKPROGRAMMABLE GAMMA RESISTORS VIN8 700Ω* 700Ω* 700Ω* VIN6 VIN5 700Ω* VCOM OUT 1.2V VCOM IN+ VCOM IN– VIN11 VOUT11 VOUT10 VOUT9 VOUT8 VOUT7 VOUT6 VOUT5 VOUT4 APPLICATIONS LCD TV panels LCD monitor panels VIN10 PRODUCT OVERVIEW The ADD8707 is a 12-channel integrated gamma reference with VCOM for use in LCD TV and monitor panels. The output buffers feature high current drive and low offset voltage to provide an accurate and stable gamma curve. The top six channels swing to VDD and the lower six channels swing to GND. Integrating the gamma setup resistors drastically reduces the external component count while increasing the gamma curve accuracy. To accommodate multiple column drivers and panel architectures, the ADD8707 is mask-programmable to a 0.2% resolution using the on-chip 500 resistor string. An on-board voltage regulator provides a fixed input for the resistor string, isolating the ...