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How much is built-in pull-up (pull-down) resistance?

Latest Updated:04/10/2002

Question:

(I/O Port)  How much is built-in pull-up (pull-down) resistance ? [2002/04/10]

Answer:

Computing methods are described below. Please calculate for your device using its specifications.

(1) Pull-Up Resistance

When Vcc is 5 V and IIL of port PXx in pull-up is the value indicated in the following table, the built-in pull-up resistance value is obtained using Ohm's Law as shown below.
Therefore, the built-in pull-up resistance values for this device are max. 250kΩ, standard 83.3kΩ and min. 41.7kΩ.

Symbol Parameter Measurement condition Ratings Unit
Min. Typ. Max.
IIL "L" input current PXx
(at pull-up)
VI=Vss
Vcc=5V
-20 -60 -120 micro-A

(2) Pull-Down Resistance

When Vcc is 5V and IIH of port in pull-down is the value indicated in the following table, the built-in pull-down resistance value is obtained using Ohm's Law as shown below.
Therefore, this built-in pull-down resistance values for this device are max.
166.7kΩ, standard 71.4kΩ and min. 35.7kΩ.

 

Symbol Parameter Measurement condition Ratings Unit
Min. Typ. Max.
IIH "H" input current PXx
(at pull-down)
VI=Vcc
Vcc=5V
30 70 140 micro-A

(#105177)

Suitable Products
3803H
3803L
3823
3850A
3858
38D2
38D5
7544
7546
7547
7548
7549
3874