SN65HVD37: Voh lower than requirement

David Huang

Part Number: SN65HVD37

Hi team,

My customer is using SN65HVD37DR in their new design.

They recently found that the device's Voh min=2.4V＠Ioh=-8mA, which is lower than the MCU they are using, with Vih=2.7V.

The board is already fixed and there's little change they can do to the design, and the customer doesn't want to change to another device at this timing.

Is it possible to lower the Ioh for higher Voh? Is there anything else the customer can do to raise the Voh?

Regards

over 1 year ago

0 Clemens Ladisch over 1 year ago

Guru 316780 points

Does the MCU input actually sink 8 mA? When connected to a high-impedance CMOS input, the actual V_OH will be near 3.3 V. See [FAQ] What is the output voltage (VOH or VOL) when the output current is X or the supply voltage is Y?

0 Parker Dodson over 1 year ago

TI__Guru 52192 points

Hi David,

If the MCU input is high impedance where you are drawing very little current from the output of the SN65HVD37 the output voltage should be be closer to VCC (3.3V). 8mA is generally a lot of current coming out of the receiver - so most applications generally have better performance that what is spec'd because 8mA is generally much more than is actually sourced from the SN65HVD37. However there is risk because of how we spec it - I don't anticipate a lot of issues with standard MCU connections like this but in the future they should address the mismatch.

Best,

Parker Dodson

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SN65HVD37: Voh lower than requirement