18-Channel GAMMA VOLTAGE GENERATOR
Description
BUF20820
SBOS330C − DECEMBER 2005 − REVISED OCTOBER 2006
18-Channel GAMMA VOLTAGE GENERATOR with Two Programmable VCOM Channels
FEATURES
D 18-CHANNEL GAMMA CORRECTION D 2-CHANNEL PROGRAMMABLE VCOM:
100mA IOUT
APPLICATIONS
D D
D REPLACES RESISTOR-BASED GAMMA
SOLUTIONS TFT-LCD REFERENCE DRIVERS DYNAMIC GAMMA CONTROL
D D D D D D D
ON-CHIP OTP MEMORY 10-BIT RESOLUTION RAIL-TO-RAIL OUTPUT LOW SUPPLY CURRENT: 900µA/ch SUPPLY VOLTAGE: 7V to 18V DIGITAL SUPPLY: 2.
0V to 5.
5V INDUSTRY-STANDARD, TWO-WIRE INTERFACE: 3.
4MHz HIGH-SPEED MODE 4kV HBM, 1kV CDM, 200V MM
DESCRIPTION
The BUF20820 is a programmable voltage reference generator designed for gamma correction in TFT-LCD panels.
It provides 18 programmable outputs for gamma correction and two channels for VCOM adjustment, each with 10-bit resolution.
It offers on-chip One-Time Programmable (OTP) memory that allows the user to store the gamma voltages on-chip.
This eliminates the need for an external EEPROM.
This programmability replaces the traditional, timeconsuming process of changing resistor values to optimize the various gamma voltages and allows designers to determine the correct gamma voltages for a panel very quickly.
Required voltage changes can also be easily implemented without hardware changes.
The BUF20820 uses TI’s latest, small-geometry analog CMOS process, which makes it a very competitive choice for full production, not just evaluation.
Programming of each output occurs through an industrystandard, two-wire serial interface.
Unlike existing programmable buffers, the BUF20820 offers a high-speed mode that allows clock speeds up to 3.
4MHz.
For lower or higher channel count, please contact your local sales or marketing representative.
OUT 17 OUT 18
D HIGH ESD RATING: D DEMO BOARD AND SOFTWARE AVAILABLE
www.
DataSheet4U.
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2V−5.
5V Digital BUF20820
7V−18V Analog REFH
REFH OUT
OUT 1
OUT 2
… …
DAC Registers 1 Program Command OTP Memory
DAC Registers 2
…
18 Output Channels plus Two VCOM Channels
The...
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