AN404 discusses the F-RAM RTC processor companion’s backup power sources, the internal charging circuit, and the associated issues.
Overview
The FM31xx and FM33xx families are the Integrated Processor Companion devices that feature a real-time clock (RTC). The RTC provides the date/time information for the system and operates on either VDD or VBAK power. A battery or a capacitor is attached to the VBAK backup power-supply pin. This application note discusses the backup power sources, the internal charging circuit, and the associated issues.
↧
AN404 - F-RAM RTC Backup Supply (VBAK pin) and UL Compliance
↧