The MAX8784 evaluation kit (EV kit) is a fully assembled
and tested surface-mount PCB that provides the voltages
and features required for active-matrix, thin-film
transistor (TFT) liquid-crystal display (LCD) panels in
LCD monitors and LCD TVs. The EV kit contains a step-up
switching regulator, a two-stage positive charge
pump for the TFT gate-on supply, a single-stage negative
charge pump for the TFT gate-off supply, and three
high-current op amps. Two capacitor-control delays are
available: one to control the initial startup of the step-up,
and the other to control the delay between the negative
and positive charge pumps. Also included is a
logic-controlled, high-voltage switch for the positive
gate-driver supply. A high-voltage stress (HVS) mode is
provided to increase the step-up and the positive
charge-pump output voltages for stress testing the display
panel during production. A capacitive dummy load
is provided at the high-voltage switch output for ease of
testing without a panel attached.
The EV kit operates from a DC supply voltage of +4.5V
to +5.5V, as configured. The step-up switching regulator
is configured for a +14V output providing at least
700mA. The positive charge pump is configured for a
+28V output providing at least 50mA. The negative
charge pump is configured for a -9V output providing at
least 50mA. The three high-current op amps are each
configured for a +7V output that can source or sink
180mA. The high-voltage switch can be controlled by
external logic. The EV kit's input voltage range can be
lowered to +4V at slightly lower load currents.
The MAX8784 step-up switching regulator operates at
1.2MHz, allowing the use of tiny surface-mount components.
The MAX8784 thin QFN package (0.8mm max
height), with low-profile external components, allows
this circuit to be less than 3mm high.
Key Features
Applications/Uses
+4.5V to +5.5V Input-Voltage Range
Output Voltages
+14V Output at 700mA (Step-Up Switching Regulator)
+28V Output at 50mA (Positive Charge Pump)
-9V Output at 50mA (Negative Charge Pump)
Three High-Current Op Amps (±180mA)
1.2MHz Switching Frequency
All Output Voltages are Resistor Adjustable
Logic-Controlled, High-Voltage Switch
High-Voltage Stress Mode for the Step-Up and Positive Charge-Pump Output Voltages
Capacitor-Controlled Initial Startup Delay and Positive Charge-Pump Delay
* Some packages have variations, listed on the drawing. "PkgCode/Variation" tells which variation the product uses. Note that "+", "#", "-" in the part number suffix describes RoHS status. Package drawings may show a different suffix character.
Devices:
1-1 of 1
MAX8784EVKIT
Free Sample
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Status
Package:
TYPE PINS FOOTPRINT
DRAWING CODE/VAR *
Temp
RoHS/Lead-Free? Materials Analysis
MAX8784EVKIT+
Active
Land Pattern: Not Available
See data sheet
Related Products
MAX8784 Step-Up Regulator, Internal Charge Pumps, Switch Control, and Operational Amplifier for TFT LCDs
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