SN55189A: Need information on the (0 to 70degC) ratings.

Komal Charan Garlapati

Part Number: SN55189A
Other Parts Discussed in Thread: MC1489A, , SN75C189A

Hi,

We are planning to replace MC1489AN with SN55189AJ as MC1489AN is in LTB.

MC1489AN's operating temperature range is 0°C to 70°C and SN55189AJ's operating temperature range is –55°C to 125°C.

The Positive-going input threshold voltage is not given at 0°C to 70°C for the MC1489AN (1.55V to 2.25V) and –55°C to 125°C for the SN55189AJ (1.30V to 2.65V) part. I wanted to know if SN55189AJ is being operated at 0°C to 70°C, will it have same value as MC1489AN?

The Negative-going input threshold voltage is not given at 0°C to 70°C for the MC1489AN (0.65V to 1.25V) and –55°C to 125°C for the SN55189AJ (0.35V to 1.6V) part. I wanted to know if SN55189AJ is being operated at 0°C to 70°C, will it have same value as MC1489AN?

Thank you,

Komal Garlapati.

over 1 year ago

+1 Clemens Ladisch over 1 year ago

Guru 316690 points

The MC1489A and SN55189A share a datasheet, which usually implies that they use the same die. All other characteristics are identical, so I would expect the SN55 to have the same limits in the narrower temperature range. (But there is no guarantee.)

Why aren't you using the SN75C189A? The input threshold voltages matter only when you are using logic voltages on the RS-232 bus (which is unlikely, because you would still need to invert the signals). RS-232 signals have at least ±3 V and are not critical.

0 Eric Hackett over 1 year ago in reply to Clemens Ladisch

TI__Guru 74252 points

Komal,

Clemens is correct here, but I've also assigned an engineer from TI to respond. They will get back to you by the end of the week.

Regards,

Eric Hackett

+1 BOBBY over 1 year ago

TI__Guru 72771 points

Hi Komal,

As Clemen's has pointed out the characteristics of the two devices are the same within those temp ranges. The main difference between the two devices is differences in bond wire and SN55 goes through a much more thorough set of checks before they are shipped.

-Bobby

0 Komal Charan Garlapati over 1 year ago in reply to Clemens Ladisch

Prodigy 80 points

Hi Clemens,

Thank you for your answer. The SN75C189A has some slight variations in the threshold levels when compared to those of MC1489A. Thanks for the suggestion. I'll evaluate SN75C189A and proceed with it if these variations are acceptable. (I think it will be acceptable as these are minor).

0 Komal Charan Garlapati over 1 year ago in reply to Eric Hackett

Prodigy 80 points

Thank you Eric.

0 Komal Charan Garlapati over 1 year ago in reply to BOBBY

Prodigy 80 points

Ok Bobby. Thank you for explaining the differences.

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SN55189A: Need information on the (0 to 70degC) ratings.