Rainbow Electronics MAX1677 - Manual (Page 15)

MAX1677
Compact, High-Efficiency, Dual-Output
Step-Up and LCD Bias DC-DC Converter
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reduce the output filter to 2.2µF. Ceramic capacitors will
exhibit lower ripple than equivalent value (or even higher
value) tantalums due to lower ESR.
Layout Considerations
The MAX1677’s high-frequency operation makes PC
board layout important for minimizing ground bounce
and noise. Protect sensitive analog grounds by using a
star ground configuration. Minimize ground noise by
connecting PGND, the input bypass-capacitor ground
terminal, and the output filter-capacitor ground terminal
to a single point (star ground configuration). Also, mini-
mize lead lengths to reduce stray capacitance and
trace resistance. Where an external resistor-divider is
used to set output voltage, the trace from FB or LCDFB
to the feedback resistors should be extremely short to
minimize coupling from LX and LCDLX. To maximize
efficiency and minimize output ripple, use a ground
plane and connect the MAX1677 GND and PGND pins
directly to the ground plane. Consult the MAX1677
evaluation kit for a full PC board example.
Chip Information
TRANSISTOR COUNT: 1221