LM8207MTSLASHNOPB datasheet(20/32 Pages) TI1

20 / 32 page

DISPLAY

VCOM

REFERENCE

VREF

5 k:

VCOM

BUFFER

LM8342

LM8207

SNOSAL5A – SEPTEMBER 2005 – REVISED MARCH 2013

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Figure 40. VCOM Buffer

The typical application in Figure 40 shows the VCOM buffer supplying a common voltage to the back plate of the

display. This level can be adjusted by changing the value of the resistors. Increasing the value of R1 or

decreasing the value of R2 will decrease the VCOM level. Increasing the value of R2 or decreasing the value of R1

will increase the VCOM level.

Another, more flexible, solution is to use Texas Instruments’ programmable VCOM calibrator, the LM8342. The

VCOM level can be adjusted using an I

2C interface. See the LM8342 Programmable TFT V COM Calibrator with

Non-Volatile Memory datasheet (literature number: snosam0) for more detailed information about this part.

LM8207 CONFIGURATION

A complete configured typical application of the LM8207 is given in Figure 41. All three basic functions of the

LM8207 are discussed in the previous sections. Details for setting the Voltage Reference are given in the

“Voltage Reference” section. Calculations for defining a gamma correction curve are given in the section entitled

“Gamma Buffers.” Defining and adjusting the VCOM level is discussed in the “VCOM Buffer” section. The LM8207 is

an 18 channel gamma buffer plus a VCOM buffer. In certain applications some of the gamma buffers or the VCOM

buffer may not be used. In such cases it is recommended that the unused buffer input pins be tied to the input

voltage range value.

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LM8207MT/NOPB Datasheet(PDF) 20 Page - Texas Instruments