The MAX17088 includes a high-performance, step-up
regulator; a high-speed operational amplifier; a digitally
adjustable VCOM calibration device with nonvolatile
memory; an I²C interface; and a high-voltage, level-shifting
scan driver. The device is optimized for thin-film
transistor (TFT) liquid-crystal display (LCD) applications.
The MAX17088 is the successor to the MAX8798.
The step-up DC-DC converter provides the regulated
supply voltage for panel source driver ICs. The converter
is a 1.2MHz current-mode regulator with an integrated
20V n-channel power MOSFET. The high switching
frequency allows the use of ultra-small inductors and
ceramic capacitors. The current-mode control architecture
provides fast transient response to pulsed loads
typical of source driver loads. The step-up regulator
features soft-start and current limit.
The high-current operational amplifier is designed to drive
the LCD backplane (VCOM). The amplifier features high
output current (±150mA), fast slew rate (45V/µs), wide
bandwidth (20MHz), and rail-to-rail inputs and outputs.
The programmable VCOM calibrator is externally
attached to the VCOM amplifier's resistive voltage-divider
and sinks a programmable current to adjust the VCOM
output-voltage level. An internal 7-bit digital-to-analog
converter (DAC) controls the sink current. The DAC is
ratiometric relative to BOOST and is guaranteed to be
monotonic over all operating conditions. The calibrator IC
includes an MTP to store the desired VCOM voltage
level. The 2-wire, I²C interface between the LCD panel
and the programming circuit minimizes panel connector
lead count and simplifies production equipment.
The high-voltage, level-shifting scan driver is designed
to drive the TFT panel gate drivers. Its three outputs
swing 65V (maximum) between +45V (maximum) and
-25V (minimum) and can swiftly drive capacitive loads.
To save power, the two complementary outputs are
designed to allow charge sharing during state changes.
The MAX17088 is available in a 36-pin (6mm x 6mm),
thin QFN package with a maximum thickness of 0.8mm
for ultra-thin LCD panels.
