Analog Devices Inc. ADEMA124/ADEMA127 24-Bit Sigma-Delta ADCs

The ADI ADEMA124 and ADEMA127 incorporate sinc compensation, low-pass filtering, and a DSP decimate-by-2 function, extending the usable analog bandwidth by up to 70% for a given output sample rate. This high bandwidth makes the components suitable for IEC 61000-4-30 Power Quality Class A and Class S meters. These ADCs also support compliance with active energy standards such as IEC 62053-21, IEC 62053-22, OIML R46, and ANSI C12.1, as well as reactive energy standards including IEC 62053-23, IEC 62053-24, and EN 50470-3. With a fast start-up time of just 0.5ms (typical), the ADEMA124 and ADEMA127 ADCs are ideal for circuit breakers and protection relays, particularly when used with Rogowski sensors.

For configuration and data retrieval, the ADCs provide a flexible SPI interface with daisy-chain capability, allowing multiple ADCs to be serviced through a single SPI port and reducing pin count on the host microcontroller. The components are also daisy-chain compatible with the ADE9112/ADE9113 isolated ADCs. To ensure data integrity, independent cyclic redundancy checks (CRC) are implemented to detect errors in SPI communication and prevent unintended changes to configuration registers.