Posted on February 17, 2004 at 22:47The datasheet is unclear in the operation of the ST72F621L4M1. On the one hand there is an internal low voltage detection circuit that one might assume provides a guaranteed device state at low voltage, but is only guaranteed to work below 3.45V (falling edge). On the other hand you have a device specification that claims the safe operating area of the device is only down to 4.0V. There is no specification for what might happen between 3.45V and 4.0V, and yet this is a voltage region that the processor must pass through in normal operation.
The rising voltage is not a concern as the datasheet does give the times in which rising voltages must be stabilized above the safe operating voltage, and until that time has elapsed the device is held in reset. But there is insufficient data to design for falling voltages. Is anyone aware of an official standpoint from ST on this issue?
