JAJSVQ2 November 2024 LM644A2-Q1
PRODUCTION DATA
The choice of switching frequency is a compromise between conversion efficiency and overall design size. Lower switching frequency implies reduced switching losses, usually resulting in less power dissipated in the IC. Lower power dissipated in the IC results in higher system efficiency and a lower IC temperature. However, higher switching frequency allows the use of smaller inductors and output capacitors, hence, a more compact design. Many applications require that the AM band be avoided. These applications tend to operate at around 400kHz (below the AM band), or 2.1MHz (above the AM band). For 400kHz, a 39.2k 1% resistor can be used. For this 2100kHz example, a 7.15k 1% resistor is selected.