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You have to be more specific, in which device are you referring?
The disable pin usually leaves the pin floating, if you want to force a value then use a pull up/down resistor, 10K-47K should be fine
Check IC datasheet. It has reference application circuit that shows if this pin should be pulled high or low, and the pull resistor values.
Usually 10k resistor is used for 5V devices, and 4k7 for 3.3V and 2.5V devices.
In this way, you do not need to calculate any value.
You have to be more specific, in which device are you referring?
The disable pin usually leaves the pin floating, if you want to force a value then use a pull up/down resistor, 10K-47K should be fine
You can refer to old circuit books on TTL.
I remember there is a chart showing the overshoots, undershoots, ringing effects, RC charging and discharging time constants etc, when used with different resistors.
I recall that 4k7 to 10k gives good pull on the line, so it gets well above threshold voltage at the input, as well as minimal ringing effects like over/undershoots.
These octal buffers and line drivers are designed
specifically to improve the performance and
density of 3-state memory address drivers, clock
drivers, and bus-oriented receivers and
transmitters.
The ’AC244 devices are organized as two 4-bit
buffers/drivers with separate output-enable (OE)
inputs. When OE is low, the device passes
noninverted data from the A inputs to the Y
outputs. When OE is high, the outputs are in the
high-impedance state. To ensure the high-impedance state during power
up or power down, OE should be tied to VCC
through a pullup resistor; the minimum value of
the resistor is determined by the current-sinking
capability of the driver.
NOTE 3: All unused inputs of the device must be held at VCC or GND to ensure proper device operation. Refer to the TI application report,
Implications of Slow or Floating CMOS Inputs, literature number SCBA004.
TI app. report SCBA004 here.................
**broken link removed**
Enable and disable are directly given as LOW or HIGH input depending on their active value. These are input pins. Pull up resistor is required for output ports to pull up port to HIGH. The value of the resistor depends on your output current requirements. This details also can be found in IC datasheet.
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