STPM12 datasheet(33/46 Pages) STMICROELECTRONICS

33 / 46 page

STPM11, STPM12, STPM13, STPM14

Theory of operation

Doc ID 13167 Rev 8

33/46

Permanent writing of the CFG bits

In order to make a permanent set of some CFG bits, use the following procedure:

1. collect all addresses of CFG bits to be permanently set into a list;

2. clear all OTP shadow latches;

3. set the system signal RD;

4. connect a current source of at least +14 V, 1 mA to 3 mA to VOTP;

5. wait for VOTP voltage to be stable;

6. set one OTP shadow latch from the list;

7. set the system signal WE;

8. wait for 300 s;

9. clear the system signal WE;

10. clear the OTP shadow latch which was set in step 6;

11. until all CFG bits are permanently set as desired, repeat steps 5 to 11;

12. disconnect the current source;

13. wait for VOTP voltage to be less than 3 V;

14. clear the system signal RD;

15. verify the correct writing, testing STPM1x operation;

16. if the verification of CFG bits fails, repeat steps 1 to 16.

For steps of set or clear, apply the timing shown in Figure 21 - with proper signal on the

SDA-TD.

In order to create a permanent set of the TSTD bit, which does not result in any more writing

to the Configuration bits, the procedure above must be conducted in such a way that steps 6

to 13 are performed in series during a single period of active SCS. The idle state of SCS

would make the signal TSTD immediately effective which in turn, would abort the procedure

and possibly destroy the device due to clearing of system signal RD. This would result in the

connecting of all gates of 3 V NMOS sense amplifiers of already permanently set CFG bits

to the VOTP source.

Obsolete

Product(s)

- Obsolete

Product(s)

STPM12 Datasheet(PDF) 33 Page - STMicroelectronics