Online digital trimming procedure

SEA01

18/24

DocID024452 Rev 1

the user has to pay attention that, during the step-up of Vcc before the burning of the NVM,

a negative ringing on Vcc will cause a drop below the UVLO of the IC.

storing these values in an external memory (ATE, industrial PC, etc.), then increasing Vcc to

19 V and waiting to have a stable Vcc level. The user can then resend the selected value of

the NVM (OTP) in a single step.

It is possible to burn the NVM by sending the burn command (write) given in Table 5

followed by a data byte with the same code as a burn command.

It is important to provide a zapping time of at least 45 msec and to have Vcc of the IC equal

to 19 V with a current capability of 90 mA, in order to ensure correct blowing of the anti-fuse

45 ms in order to perform the burning of the NVM.

To protect the NVM memory from an incorrect write, if the parity fail flag was activated, i.e.

an error occurred during the trimming process, the burn command is not executed.

The NVM is written only if it was never written or written one time. If the NVM is written a

second time, the previous content is lost.

Please note that after a Write NVM command the Status Register is not automatically

updated. It must be updated by turning off and on again the IC or by sending a Reload NVM

command to the device. Once the update is performed, the number of times the IC has been

burned can be read from the status register.

Byte 1

(address, write type)

Byte 2:

command

Byte 3

(address, read type)

x

Sent by slave (device)

x

x

Sent by master