54AC164245 Datasheet, PDF (3/22 Pages) STMicroelectronics – Rad-hard 16-bit transceiver, 3.3 V to 5 V bidirectional level shifter

54AC164245
Functional description
1.1
Cold spare
The 54AC164245 features a cold spare input and output buffers. In high reliability
applications, cold sparing enables a redundant device to be tied to the data bus with its
power supply at 0 V (V_DD = V_SS, V_DD - V_SS = 0 V) without affecting the bus signals or
injecting current from the I/Os to the power supplies. Cold sparing also allows to keep
unpowered redundant devices so that they can be switched on only when required. Power
consumption is therefore reduced by switching off the redundant circuit. This has no impact
on the application. Cold spare is achieved by implementing a high impedance between I/Os
and V_DD. The ESD protection is ensured through a non-conventional dedicated structure.
1.2
Power-up
During power up, all outputs are forced to high impedance. The high-impedance state is
maintained approximately until V_DD is high, thus avoiding any transient and erroneous
signals during power-up.
1.3
Pin connections
Figure 2. Pin connections




!-V
Doc ID 18093 Rev 2
3/22