MAX9665ETP+ Maxim Integrated, MAX9665ETP+ Datasheet - Page 32

• Manufacturer Part Number: MAX9665ETP+
• Description: LCD Gamma Buffers 6/8/10-Channel 10-Bit Nonvolatile Programmable Gamma and VCOM Reference Voltages
• Manufacturer: Maxim Integrated

6/8/10-Channel, 10-Bit, Nonvolatile Programmable
Gamma and VCOM Reference Voltages
Often, CTL and CE are exposed at the panel connector
and are therefore subject to electrostatic discharge
(ESD). Resistor-capacitor (RC) filters can be employed
at these inputs to improve their ESD performance
(Figure 14).
If the CE panel connector is to be left unconnected
after programming, be sure to include a resistor to
ground (R
time constant for a CE filter is not critical, but the driving
resistor must have a much lower resistance than R
properly drive CE. If a filter is used at the CTL panel
connector, its RC time-constant should be short enough
to avoid interfering with CTL pulses or MTP memory
programming timing. A time constant less than 200µs
does not interfere with MTP memory programming. To
avoid interfering with CTL pulses, make the time con-
stant small compared to the CTL pulse width needed.
Figure 14. Improved EOS/Surge Performance
32
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CE
Electrostatic Discharge (CTL, CE)
) to ensure a valid logic-low on CE. The
AFTER PROGRAMMING
AFTER PROGRAMMING
PROGRAMMING
UNCONNECTED
UNCONNECTED
DVDD DURING
10kΩ
1kΩ
100kΩ
R
CE
CE
to
0.1µF
0.1µF
The CTL pin is internally biased to DVDD/2, but it is
sensitive to leakage currents above 0.1µA. When CTL is
not driven, avoid leakage currents around the CTL pin.
Otherwise, reinforce the DVDD/2 set point with an exter-
nal resistive voltage-divider.
The MAX9665/MAX9666/MAX9667 operate from a single
9V to 20V analog supply and a 2.5V to 3.6V digital sup-
ply. Bypass AVDD to GND with 0.1µF and 10µF capaci-
tors in parallel. Use an extensive ground plane to ensure
optimum performance. Bypass DVDD to GND with a
0.1µF capacitor. Refer to the MAX9665/MAX9666/
MAX9667 evaluation kit for a proven PCB layout.
The exposed pad on the TQFN package is electrically
connected to GND. Solder the exposed pad to a
ground plane to provide a low thermal resistance to
ground for heat dissipation. Do not route traces under
these packages.
Power Supplies and Bypass Capacitors
CTL
CE
MAX9665
MAX9666
MAX9667
GND
Leakage Current (CTL)
Layout and Grounding