The RX21A group is the product that 24-bit Delta-sigma ADC is built in for measuring instruments such as a smart meter.PGA (Programmable Gain Amp) is built in Delta-sigma ADC, which is possible to amplify analog signal at most 64 times.The RX21A group has peripheral functions with special features, such as RTC which enables Time capture on event-signal input through external pins and DEU (Data Encryption Unit) which enables to use Encryption/decryption functions of the AES standard.