STMPE1600 datasheet(19/27 Pages) STMICROELECTRONICS

19 / 27 page

STMPE1600

Polarity inversion register

Doc ID 16938 Rev 3

19/27

9.3

Fail safe conditions

The STMPE1600 IOs (SDA, SCL, INT, A2, A1, A0) are fail-safe IOs that support 4 mA

current drive.

Note that “present” state implies that the supply is present. The “absent” state implies that

the power is lost (grounded) condition. In the fail-safe condition, the leakage current flowing

into the STMPE1600 device is prevented.

Fail Safe condition

When chip supply is 0 V and when VIO (SDA, SCL, INT, A2, A1, A0) is 3.6 V, this is classified

as a fail-safe condition. In this case, the chip is protected and the current per I/O is limited to

a very small value.

Overvoltage condition

The second condition is the overvoltage condition which occurs when VCC = 1.65 V and

VIO = 3.6 V. In this condition, the current drawn by the device per IO can be 10 µA (typical)

and 25 µA (worst case). This device should not be operated under this condition.

So it is recommended to operate the IO at the same voltage as the supply voltage (either

1.8 V or 3.3 V). Also the fail safe IOs are special IOs which can have a voltage present while

the supply voltage VCC is 0 V. Current will be limited from the fail safe IOs when supply

voltage VCC is 0 V.

Table 10.

Fail safe conditions

VCC (core and IO supply)

Condition

Present

Normal operating condition

Absent

Complete power-down condition

STMPE1600 Datasheet(PDF) 19 Page - STMicroelectronics