1FEATURES

234? 24-CHANNEL GAMMA

– 22-CHANNEL PROGRAMMABLE

– 2-CHANNEL STATIC GAMMA

? 2-CHANNEL PROGRAMMABLE VCOM ? 10-BIT RESOLUTION

? 16x REWRITABLE NONVOLATILE MEMORY

? TWO INDEPENDENT MEMORY BANKS

? RAIL-TO-RAIL OUTPUT

? LOW SUPPLY CURRENT: 0.5mA/channel

? SUPPLY VOLTAGE: 9V to 20V

? DIGITAL SUPPLY: 2V to 5.5V

? I2C? INTERFACE

APPLICATIONS

? TFT-LCD REFERENCE DRIVERS

DESCRIPTION

The BUF22821 offers 22 programmable gamma

channels, two programmable VCOM channels, and two

static gamma channels. It is ideal for the new 10-bit

source drivers that require 22 gamma channels.

The final gamma and VCOM values can be stored in the on-chip, nonvolatile memory. To allow for

programming errors or liquid crystal display (LCD)

panel rework, the BUF22821 supports up to 16 write

operations to the on-chip memory. The BUF22821

has two separate banks of memory, allowing

simultaneous storage of two different gamma curves

to facilitate switching between gamma curves.

All gamma and VCOM channels offer a rail-to-rail output that typically swings to within 100mV of either

supply rail with a 10mA load. All channels are

programmed using an I2C interface that supports

standard operations up to 400kHz and high-speed

data transfers up to 3.4MHz.

The BUF22821 is manufactured using Texas

Instruments’ proprietary, state-of-the-art, high-voltage

CMOS process. This process offers very dense logic

and high supply voltage operation of up to 20V. The

BUF22821 is offered in a HTSSOP-38 PowerPAD?

package. It is specified from –40°C to +85°C.