JAJSAZ1M February 2013 – October 2020 LM22679 , LM22679-Q1
PRODUCTION DATA
The LM22679 device incorporates a floating high-side gate driver to control the power MOSFET. The supply for this driver is the external boot-strap capacitor connected between the BOOT pin and SW. A good quality 10-nF ceramic capacitor must be connected to these pins with short, wide PCB traces. One reason the regulator imposes a minimum off-time is to ensure that this capacitor recharges every switching cycle. A minimum load of about 5 mA is required to fully recharge the bootstrap capacitor in the minimum off-time. Some of this load can be provided by the output voltage divider, if used.