ACPL-M21L Digital CMOS Optocouplers Broadcom ACPL-M21L Digital CMOS Optocouplers feature a CMOS output stage and optical receiver input stages with built-in Schmitt triggers to provide logic-compatible waveforms, eliminating the need for additional waveshaping. The optocoupler consumes extremely low power, at maximum 1.1mA IDD current per channel across temperature.