AN2269 - Application Note

ST8024 Application Hardware Guidelines

19/25

A small amount of noise is introduced into the design because of the switching circuitry. In

order to reduce it and improve the efficiency of the step-up converter, the capacitors must be

connected as closely as possible to the pins (see

Figure 17). An Equivalent Series

Resistance (ESR) of lower than 100m

Ω at 100kHz is recommended.

The evaluation board is equipped with MURATA GRM31M7U1H104JA01B capacitors.

However, other capacitors with an ESR of up to 100m

Ω at 100kHz are good enough to work

within the specifications. They just may be more sensitive to the layout optimization process.

Figure 17.

ST8024 Application PCB Storage and Pumping Capacitors