ST619LB SERIES

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APPLICATION INFORMATION

Charge pump capacitors C1 and C2

The values of charge pump capacitors C1 and C2

are critical to ensure adequate output current and

avoid excessive peak currents. It is suggested to

use values in the range of 0.22

µF to 1.0µF and

order to obtain best performance. Ceramic or

tantalum capacitors are recommended.

Input and output capacitors C3 and C4

The type of input capacitor (C3) and output filter

capacitor (C4) used is not critical, but it does affect

performance. Tantalums, ceramics or aluminium

electrolytic are suggested. For lowest ripple, use

large, low effective series resistance (ESR)

ceramic tantalum capacitors. If the input supply

source impedance is very low, C3 can be omitted.

The

typical

application

circuit

shows

the

component values for proper operation using

minimal board space. The input bypass capacitor

(C3) and output filter capacitor (C4) should be at

least 10

µF. Many capacitors exhibit 40% to 50%

variation

over

temperature.

Compensate

for

capacitor temperature coefficient by selecting a

large nominal value to ensure proper operation

over temperature.

Layout Consideration

In the below figure, the

typical application

demoboard of ST619LB is reported. A good layout

ensures stability and helps maintain the output

voltage under heavy loads. For best performance,

use very short connections to the capacitors.

TYPICAL APPLICATION CIRCUIT

TYPICAL APPLICATION DEMOBOARD