SN74AHC1G09: Logic Levels

Vidhya J

Intellectual 400 points

Part Number: SN74AHC1G09

Tool/software:

Hi Team,

1. for inputs , What is the VIH and VIL levels when VDD=3.3V , 1.8V and 5V??

2. for output open drain, VOH and VOL to be considered 0V to Vpullup (pull up voltage)?

3. Can open drain output pull up be 1.8V when VDD=3.3V?

Thanks and Regards,

Vidhya

11 months ago

0 Clemens Ladisch 11 months ago

Guru 317350 points

1. Use the values specified for 3 V and 4.5 V; those are the worst case of 3.3 V ± 0.3 V or 5 V ± 0.5 V supplies. This device does not work with a 1.8 V supply.

2. V_OL is specified. V_OH is determined not by the AND gate but by the pull-up resistor (if there is any), so the datasheet cannot tell you about it. V_OH will be much lower than the pull-up voltage because of the voltage drop over the resistor, depending on the current.

3. The output can be pulled to any voltage in the V_O range specified in the recommended operating conditions.

0 Vidhya J 11 months ago in reply to Clemens Ladisch

Intellectual 400 points

My comments inline.

1. ok. Our case VCC is 3.3V.

2. VOL is specified as 0.55V for VDD=3V.

other device which interfaces with this Open Drain AND gate has VIL max of 0.54V.

There is a violation in this case as VOL of gate is not less than VIL max of other device. Please suggest.

3. ok.

Thanks,

Vidhya

0 Clemens Ladisch 11 months ago in reply to Vidhya J

Guru 317350 points

2. This V_OL is specified for a current of 4 mA. But what is the actual input current of your device? (I guess it is less than 20 µA.)

0 Vidhya J 11 months ago in reply to Clemens Ladisch

Intellectual 400 points

2. yes it is <20uA. what VOL should be considered? should it be <0.55V?

+1 Clemens Ladisch 11 months ago in reply to Vidhya J

Guru 317350 points

The electrical characteristics table tells you that for currents less than 50 µA, the voltage is less than 0.1 V.

0 Vidhya J 11 months ago in reply to Clemens Ladisch

Intellectual 400 points

Thanks Clemens

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SN74AHC1G09: Logic Levels