The LTC1401 has three power saving modes: Nap and Sleep, through the serial interface and Shutdown by setting the SHDN pin to zero. In Nap mode, it consumes only 1.5mW of power and can wake up and convert immediately. In Sleep (Shutdown) mode, it consumes 19.5W (13.5W) of power typically. Upon power-up from Sleep or Shutdown mode, a reference ready (REFRDY) signal is available in the serial word to indicate that the reference has settled and the chip is ready to convert. The 3-wire serial port allows compact and efficient data transfer to a wide range of microprocessors, microcontrollers and DSPs. , LTC and LT are registered trademarks of Linear Technology Corporation. MICROWIRE is a trademark of National Semiconductor Corporation.