SN74AVC2T245: what happens to output A if there is no power on pin VCCB?

Vittorio Loggia

Part Number: SN74AVC2T245

Schematic about SN74AVC2T245

Pin	Value
VCCA	3.3V (Power supply 1)
VCCB	3.3V (Power supply 2)
/OE	GND (pulldown resistor)
DIR1	GND (pulldown resistor)
DIR2	VCCA (pullup resistor)
B1	Output MCU 1
B2	Input MCU 1
A1	Input MCU 2
A2	Output MCU 2

what happens on pin A1 when Power supply 2 is switched off (VCCB = 0)?
If MCU 1 port (B1) go in high impedance mode, what happens on pin A1?

thanks,

Vittorio

over 5 years ago

0 Clemens Ladisch over 5 years ago

Guru 317000 points

The V_CC isolation feature ensures that if either V_CC input is at GND, both ports are in the high-impedance state.

0 Vittorio Loggia over 5 years ago in reply to Clemens Ladisch

Prodigy 45 points

Ok. So, if V_CC,B = 0 -> B1, B2 go in the high-impedance state, same way for V_CC,A.

but, if V_CC,B = 0 and if V_CC,A = 3.3V. what happens on pin A1? also high-impedance too?

0 Clemens Ladisch over 5 years ago in reply to Vittorio Loggia

Guru 317000 points

The V_CC isolation feature ensures that if either V_CC input is at GND, both ports are in the high-impedance state.

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SN74AVC2T245: what happens to output A if there is no power on pin VCCB?