After all device settings are
configured and calibration is complete, the settings can be permanently written to
the device OTP. Ideally, OTP should be written only one time, but there is some
flexibility:
- The OTP memory includes two full images of the Data Memory
configuration settings. This means a setting can be changed from the default
and changed back to the default once, then that settings can no longer be
modified. More practically, this characteristic can be used to write the OTP
in sections. For example, the main settings can be written to OTP and at a
later production step, the calibration settings can be written to OTP.
- However, partial changes to OTP are not unlimited. This is
because an OTP signature is calculated and also stored in OTP each time the
OTP is written. The device supports up to 8 different signature values, so
there is a maximum number of 8 OTP partial writes.