isl24837a

DATASHEET
To request the full datasheet, please visit www.intersil.com/products/isl24837a
ISL24837A
Features
The ISL24837A contains a programmable 10-bit,
8-channel gamma DAC generator, a programmable
10-bit, 4-channel level shifter reference generator with
external gain control, a trimmed bandgap voltage
reference, and a digitally-controlled VCOM calibrator. The
reference voltage of ISL24837A is set by the bandgap
and two external feedback resistors, so the output
voltages are independent of AVDD. The VCOM calibrator is
the sink-current output that attaches to an external
voltage divider. The desired VCOM setting is controlled by
the I2C interface. Two banks of channels with external
pin or I2C control enable fast switching between 2
different gamma curves stored in internal EEPROM.
• 8 Programmable 10-bit Gamma Voltages with
Bandgap-Trimmed Reference
The ISL24837A is available in a 32 Ld QFN package and
is specified for operation over the -40°C to +85°C
temperature range.
Related Literature*(see page 17)
• See FN6842,“8-Channel Programmable I2C TFT-LCD
Reference Voltage Generator with Band Gap Trimmed
Reference, 4-Channel Programmable Amps with
Negative Feedback Inputs, 1-Channel VCOM Op Amp,
Integrated VCOM Calibrator and 2 Banks of
Integrated EEPROM”
• 4-Channel, 10-bit Programmable Amps with
Feedback Inputs for Level Shifter Reference Voltages
• Integrated Programmable VCOM Calibrator
• 1 VCOM Op Amp
• 2 Banks of EEPROM Storage, Rewriteable >300 Times
• 10-bit Resolution on all DACs
• 20ms DAC Loading Time at Power-On
• Analog Supply: 12V to 18V @ 15mA (Unloaded)
• Digital Supply: 2.5V to 3.3V @ 1mA (Unloaded)
• I2C Interface
• Pb-free (RoHS Compliant)
Applications*(see page 17)
• TFT-LCD Column Driver Reference Generator
• General-Purpose Reference Voltage Generators
GAMMA
……..
……..
TFT-LCD PANEL
TIMING
CONTROL
(TCON)
COLUMN DRIVERS
TFT-LCD SCREEN
ISL24837A
GAMMA BUFFER
(COLUMN DRIVER
DAC REFERENCE
VOLTAGES)
VCOM
CALIBRATOR
VCOM
DRIVER
DATA LINE
GATE
DRIVERS
SELECT
LINE
STORAGE
CAPACITOR
LC
PIXEL
TFT
COMMON
(VCOM)
FIGURE 1. TYPICAL APPLICATION
August 25, 2010
FN7645.1
1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
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I2C Bus™ is a trademark owned by NXP Semiconductors Netherlands, B.V.
Copyright © Intersil Americas Inc. 2010. All Rights Reserved.
All other trademarks mentioned are the property of their respective owners.
ISL24837A
Programmable TFT-LCD VREF Generator
ISL24837A
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2
FN7645.1
August 25, 2010