Characteristic curve of SN75ALS191

HIRATA MITSUO

Other Parts Discussed in Thread: SN75ALS191

I need information of IOH-VOH and IOL-VOL characteristic curve of SN75ALS191.

Datesheet has VOH(or VOL)values of IOH=-10mA and -40mA(or 40mA).
However, customer needs VOH(or VOL)values of IOH=-5mA(or 5mA).

over 8 years ago

0 Ron Michallick over 8 years ago

TI__Guru*** 140186 points

Hirata-san,

VOH would be about 5mA * 10 ohms + 18mV *2 = 68mV higher than 10mA value. Minimum value 2.568V
VOL will be about 1/4 of 40mA value. 125mV max.

Why 18mV, because that is VBE at 1/2 current.
Why 1/4, because 1/5 is just a little too optimistic.

0 HIRATA MITSUO over 8 years ago in reply to Ron Michallick

Intellectual 490 points

Hi,Ronald-san

Thank you for your answer.
And I want additional information of SN75ALS191.

Customer needs standard（root-mean-square） deviation data of SN75ALS191's VOH and VOL voltage.
I want its data or information that can guess it.

Best Regards,
Mitsuo

0 Ron Michallick over 8 years ago in reply to HIRATA MITSUO

TI__Guru*** 140186 points

Hirata-san,

Sorry for delay. I was on vacation.
I do not have this data.

Why is this data needed?
Knowing why will help me find a solution.

0 HIRATA MITSUO over 8 years ago in reply to Ron Michallick

Intellectual 490 points

Hi, Roland-san

Its reason is that customer don't want to change their circuit.
Because their module has correct behavior.
However, they found the issue that the calculated value has out of behavior range.
They thinks that circuit has correct in IC's real ability.

Best Regards,

Mitsuo Hirata

0 Ron Michallick over 8 years ago in reply to HIRATA MITSUO

TI__Guru*** 140186 points

Mitsuo-san,

I have order samples to test in lab.
Data will be ready between Friday and Tuesday.

0 Ron Michallick over 8 years ago in reply to Ron Michallick

TI__Guru*** 140186 points

Mitsuo-san,

I recorded VOH and VOL from 0mA to 40mA.

I used three VCC [4.5V, 5V, 5.5V] and four temperatures [0C, 25C, 70C, 125C]

I still don't understand why the data is needed.

I was surprised to see 0 mA VOL wasn't closer to zero.

SN75ALS191 VOL VOH.xlsx

0 HIRATA MITSUO over 8 years ago in reply to Ron Michallick

Intellectual 490 points

Hi,Michalick-san

Thank you for your answer and the recorded data.
Customer will have satisfaction.

>I still don't understand why the data is needed.

I have only informaiton above.
I requested to sales to get information of reason.
When I receive it, I will answer you.

Thank you very much, again.
Best regards,
Mitsuo Hirata

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Characteristic curve of SN75ALS191