SN74HC573A: Output 3 State Question

Wayne Liu

Part Number: SN74HC573A

Hi,

When OE=H, the output is Z. I connected a 30Kohm resistor in each output pin and measure the voltages on the output pins, the voltages from out 1~8 are different, pin1=4.2V, pin2=4.1V, pin3=3.2V, pin4=0.5V, .... do you know why? Thanks.

over 7 years ago

0 Emrys Maier over 7 years ago

TI__Guru* 97176 points

Hi Wayne,
What does the 30kohm resistor connect to on the other end? Can you provide a schematic to show your test?

0 Wayne Liu over 7 years ago in reply to Emrys Maier

TI__Expert 8735 points

Emrys,

Sorry my mistake, the resistors are connected with GND. And no loads, this was tested on EVM>

0 Emrys Maier over 7 years ago in reply to Wayne Liu

TI__Guru* 97176 points

Hi Wayne,
We would expect to see 0V on all outputs if that's the case - it sounds like there's something wrong with your test setup.

What EVM are you using?

Can you post a picture?

Does this show the same result with a new device?

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SN74HC573A: Output 3 State Question