ADD8708_15 Datasheet, PDF (1/16 Pages) Analog Devices – 18-Channel Gamma Buffer with Regulator

FEATURES
18 precision gamma reference outputs
Mask-programmable gamma resistors:
0.2% resolution and 0.1% accuracy
Mask-programmable voltage regulator: 0.4% accuracy
Upper 9 buffers swing to VDD
Lower 9 buffers swing to GND
Single-supply operation: 7.5 V to 16.5 V
Gamma current drive: 15 mA per channel
Peak output current: 150 mA
Output voltage stable under load conditions
Pin-to-pin compatible with ADD8709
48-lead, Pb-free LQFP and LFCSP
APPLICATIONS
LCD TV panels
LCD monitor panels
GENERAL DESCRIPTION
The ADD8708 is an 18-channel integrated gamma reference for
use in high resolution LCD TV and monitors panels. The out-
put buffers feature high current drive and low offset voltage to
provide an accurate and stable gamma curve. The top nine
channels swing to VDD; the lower nine channels swing to GND.
Integrating the gamma setup resistors drastically reduces the
external component count while increasing the gamma curve
accuracy. To accommodate multiple column drivers and panel
architectures, the ADD8708 is mask programmable to a 0.2%
resolution using the on-chip 500 resistor string. An on-board
voltage regulator provides a fixed input for the resistor string,
isolating the gamma curve from the supply ripple.
The ADD8708 is specified over the temperature range of
–40°C to +105°C and comes in both a 48-lead, Pb-free,
lead-frame chip-scale package and a Pb-free, low-profile,
quad flat package.
18-Channel Gamma Buffer
with Regulator
ADD8708
FUNCTIONAL BLOCK DIAGRAM
MASK-PROGRAMMABLE
REGULATOR RESISTORS FB
V_{REG OUT} V_DD V_DD
700Ω*
GND
V_IN18
V_IN17
V_IN16
V_IN15
V_IN14
V_IN13
V_IN12
V_IN11
V_IN10
V_IN9
V_IN8
V_IN7
V_IN6
V_IN5
V_IN4
V_IN3
V_IN2
V_IN1
+
1.2V _–
700Ω*
700Ω*
700Ω*
700Ω*
700Ω*
700Ω*
700Ω*
700Ω*
700Ω*
700Ω*
700Ω*
700Ω*
700Ω*
700Ω*
700Ω*
700Ω*
700Ω*
700Ω*
GAMMA
BUFFERS
V_OUT18
V_OUT17
V_OUT16
V_OUT15
V_OUT14
V_OUT13
V_OUT12
V_OUT11
V_OUT10
V_OUT9
V_OUT8
V_OUT7
V_OUT6
V_OUT5
V_OUT4
V_OUT3
V_OUT2
V_OUT1
MASK-PROGRAMMABLE
RESISTOR STRING
*ESD PROTECTION RESISTORS
GND GND
Figure 1. 48-Lead LQFP or LFCSP
Rev. 0
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