The MAX8798 evaluation system (EV system) consists
of the MAX8798 evaluation kit (EV kit) and the Maxim
CMAXQUSB command module. A Windows® 2000/XP/Vista-compatible software is also available for use with the EV system (MAX8798EVCMAXQU+) and can be
downloaded from www.maxim-ic.com/evkitsoftware.
The MAX8798 EV kit (MAX8798EVKIT+) is a fully
assembled and tested surface-mount printed-circuit
board (PCB) that provides the features required for
active-matrix, thin-film transistor (TFT) liquid-crystal displays
(LCDs). The EV kit contains a step-up switching
regulator, positive two-stage charge pump, negative
two-stage charge pump, digitally adjustable VCOM calibration
device with nonvolatile memory, SMBus™-compatible
interface, high-speed operational amplifier (op
amp), and high-voltage, level-shifting scan driver for
thin TFT-LCD applications.
The EV kit operates from a DC supply voltage from
+1.8V to +6V. The step-up switching regulator is configured
for a +8V output providing at least 300mA from
a +2.2V input. The positive charge pump is configured
for a +21V output providing at least 20mA. The negative
charge pump is configured for a -13V output providing
at least 20mA. The op amp is capable of providing
up to ±150mA peak and features a programmable
output voltage initially configured for +3.2V. The high-voltage
level-shifting scan driver buffers inputs from
STV, CPV, and OE pads and shifts them to a desired
level to drive TFT-LCD row logic.
The MAX8798 EV kit demonstrates low quiescent current
and high efficiency (> 85%) for maximum battery
time per charge. Operation at 1.2MHz allows the use of
tiny surface-mount components. The MAX8798 thin
QFN package (0.8mm max height), with low-profile
external components, allows this circuit to be less than
1.2mm high.
The Maxim CMAXQUSB command module provides
the SMBus-compatible interface and is connected to a
PC through the universal serial bus (USB) port. The
MAX8798 EV kit software provides a graphical user
interface (GUI) for exercising the MAX8798 features.