BUF05704 Datasheet, PDF (15/25 Pages) Burr-Brown (TI) – 18 - V SUPPLY MULTI - CHANNER GAMMA CORRECTION BUFFER

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OUTPUT VOLTAGE vs OUTPUT CURRENT
18.0
17.8
17.6 BUF11704: Channels 1−5
V_DD = 18 V
T_A = 25_C
17.4 ^{BUF07704: Channels 1−3}
17.2 ^{BUF06704: Channels 1−3}
17.0 ^{BUF05704: Channels 1−2}
1.0
0.8 ^{BUF11704: Channels 6−10}
BUF07704: Channels 4−6
0.6 _{BUF06704: Channels 4−6}
0.4 _{BUF05704: Channels 3−4}
0.2
0
0 5 10 15 20 25 30 35 40 45 50
Output Current − mA
Figure 24. Gamma Buffer Drive Capability
APPLICATIONS WITH >10 GAMMA CHANNELS
When a greater number of gamma correction channels
are required, two or more BUFxx704 devices can be
used in parallel, as shown in Figure 25. This capability
provides a cost-effective way of creating more refer-
ence voltages over the use of quad-channel op amps or
buffers. The suggested configuration in Figure 25
simplifies layout. The various different channel versions
provide a high degree of flexibility and also minimize
total cost and space.
BUF11704
OUT1
OUT2
OUT3
OUT4
OUT5
OUT6
OUT7
OUT8
OUT9
OUT10
OUT1
OUT2
OUT3
OUT4
OUT5
OUT6
BUF07704
GMA1
2
3
4
5
6
7
8
9
GMA10
GMA11
12
13
14
15
GMA16
Figure 25. Creating > 10 Gamma Voltage
Channels
BUF05704, BUF06704
BUF07704, BUF11704
SBOS277E − JUNE 2004 − REVISED DECEMBER 2004
MULTIPLE V_COM CHANNELS
In some LCD panels, more than one V_COM driver is
required for best panel performance. Figure 26 uses
three BUF07704s to create a total of 18 gamma-correc-
tion and three V_COM channels. This solution saves
considerable space and cost over the more convention-
al approach of using five or six quad-channel buffers or
op amps.
BUF07704
OUT1
OUT2
OUT3
OUT4
OUT5
OUT6
GMA1
2
3
4
5
GMA6
V_COM1
V_COM1
BUF07704
OUT1
OUT2
OUT3
OUT4
OUT5
OUT6
GMA7
8
9
10
11
GMA12
V_COM2
V_COM2
BUF07704
OUT1
OUT2
OUT3
OUT4
OUT5
OUT6
GMA13
14
15
16
17
GMA18
V_COM3
V_COM3
Figure 26. 18-Channel Application with Three
Integrated V_COM Channels
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