SN65HVD11 Senak voltage from signal line to Vcc line at not supplying Vcc.

Masahiko,

Testing in the lab today confirmed that if Vcc is left with no supply and there is a signal at the input pins, the Vcc pin will see a voltage increase. A 3V signal on the input pin A caused Vcc to rise to around 0.8 V. Increases in the input voltage up to 12 V showed that the Vcc pin voltage would not raise above 0.9V. This is due to the resistor network shown in the diagram, and unfortunately we do not have any available parts that can isolate Vcc from the input when Vcc unpowered. Although Vcc will rise with these input signals, the chip will not power on and will not give false receiver readings even in a worst case scenario when Vcc is unpowered and the A/B lines are set to 12 V.

If voltage leakage is a major concern, the best option I can point you to is the SN65HVD1781. In testing, with a 3 V signal on the A line, Vcc rose to only 0.35 V as opposed to 0.8V with the SN65HVD11.

Best Regards,

Casey McCrea

Hello Masahiko,

After testing, I've found that for 3V input signals, the leakage is identical for the SN65HVD11 and the SN65HVD75. With higher level input signals however, the SN65HVD75 has worse voltage leakage performance than the SN65HVD11. The maximum leakage found on the HVD11 was .96 V in a worst case scenario when the input voltage was 12 V. With the HVD75, the maximum leakage was 1.2 V with the input at 12 V. This is most likely due to the fact that the HVD75 does not have diodes between Vcc and the input like the HVD11 as shown below:

If the line will only see 3 V signals then both devices should perform the same.

Best Regards,

Casey McCrea