Regulated 5V Charge-Pump

DC-DC Converter

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7

Layout Considerations

The MAX619’s high oscillator frequency makes good

layout important. A good layout ensures stability and

helps maintain the output voltage under heavy loads.

For best performance, use very short connections to

the capacitors.

Paralleling Devices

Two MAX619s can be placed in parallel to increase

output drive capability. The IN, OUT, and GND pins

can be paralleled, but C1 and C2 pins cannot.

The

input bypass capacitor and output filter capacitor are,

to some extent, shared when two circuits are paral-

leled. If the circuits are physically close together, it

may be possible to use a single bypass and a single

output capacitor, each with twice the value of the single

circuit. If the MAX619s cannot be placed close togeth-

er, use separate bypass and output capacitors. The

amount of output ripple observed will determine

whether single input bypass and output filter capacitors

can be used.

___________________Chip Topography

C1+

C1-

SHDN

GND

0.115”

(2.921mm)

IN

OUT

C2+

C2-

0.072”

(1.828mm)

TRANSISTOR COUNT: 599;

SUBSTRATE CONNECTED TO GND.

MAX619

IN

OUT

GND

INPUT

5V, 40mA

MAX619

IN

OUT

GND

Figure 3. Paralleling Two MAX619s