# Hysteresis function on IOMUX receiver

Question asked by Takayuki Ishii on May 31, 2017
Latest reply on May 31, 2017 by Takayuki Ishii

Hello,

I try to understand about hysteresis function on IOMUX receiver by datasheet and

Influence of Pin Setting on System Function and Performance.

Following is a my understanding.

Is it correct?

|   min  |   typ  |   max  |
------+--------+--------+--------+------
Vhys  |   250  |   ---  |   ---  | mV
VT+  |0.5*ovdd|   ---  |   ---  | V
VT-  |   ---  |   ---  |0.5*ovdd| V

0.5* 3.3  = 1.65
0.5* 1.8  = 0.9
0.5* 0.25 = 0.125

transittion  |   ovdd  |  min
----------------+---------+-------
L -> H     |   3.3   | 1.775 = 1.65+ 0.125
L -> H     |   1.8   | 1.025 = 0.9 + 0.125

transittion   |   ovdd  | max
----------------+---------+-------
H -> L     |   3.3   | 1.525 = 1.65- 0.125
H -> L     |   1.8   | 0.775 = 0.9 - 0.125

for ovdd=3.3v
|
+---------------+------
|       |       |
|       |       | T+ = 1.775
-----|-------+-------|----------
|<------------->| Vhys = 250mV
|       |       |
----+---------------+
:       |
:
T- = 1.525

for ovdd=1.8v
|
+---------------+------
|       |       |
|       |       | T+ = 1.025
-----|-------+-------|----------
|<------------->| Vhys = 250mV
|       |       |
----+---------------+
:       |
:
T- = 0.775

Best regards,

Ishii.