BUF12800 Datasheet, PDF (5/20 Pages) Burr-Brown (TI) – REFERENCE VOLTAGE GENERATOR for LCD GAMMA CORRECTION

BUF12800
www.ti.com
APPLICATIONS INFORMATION
The BUF12800 programmable voltage reference allows
fast and easy adjustment of 12 programmable reference
outputs, each with 10-bit resolution. It allows very simple,
time-efficient adjustment of the gamma reference
voltages. The BUF12800 is programmed through a
high-speed standard two-wire interface. The BUF12800
features a double-register structure for each DAC channel
to simplify the implementation of dynamic gamma control
(see the Dynamic Control section). This allows pre-loading
of register data and rapid updating of all channels
simultaneously.
Buffers A−F are able to swing to within 300mV of the
positive supply rail, and to within 1.1V of the negative
SBOS315 − DECEMBER 2004
supply rail. Buffers G−L are able to swing to within 1.7V
of the positive supply rail, and to within 300mV of the
negative supply rail. (See the Electrical Characteristics
table for further information).
Each buffer is capable of full-scale change in output
voltage in less than 4µs; see Figure 4, typical
characteristic Full-Scale Output Swing.
Figure 7 shows the BUF12800 in a typical configuration.
In this configuration, the BUF12800 device address is 74h.
The output of each DAC is immediately updated as soon
as data is received in the corresponding register (LD = 0).
For maximum dynamic range, set V_REFH = V_S − 0.2V and
V_REFL = V_S + 0.2V.
V_S
10µF
100nF
BUF12800
1 V_S
Out L 24
2 V_S
Out K 23
3 REFH
Out J 22
(1)
(1)
Source
Driver
(1)
3.3V
1µF
100nF
Timing
Controller
4 V_DS
5 SCL
6 SDA
Out I 21
Out H 20
Out G 19
(1)
(1)
(1)
(1)
7 A0
Out F 18
8 LD
(1)
Out E 17
(1)
9 GND_D(2)
Out D 16
(1)
V_S
10 REFL
Out C 15
(1)
11 GND_A(2)
Out B 14
(1)
12 GND_A(2)
Out A 13
(1) _{RC combination optional.}
(2) _{GNDD and GNDA are internally connected and must be at the same voltage potential.}
Figure 7. Typical Application Configuration
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