MAX335 Logic Thresholds at VL = 3.3V

Hi, bgodk. 

In the Power-Supply Operation section of the product datasheet, it is mentioned that the VL supply sets TTL input compatibility at a 1.6 V switching threshold. As VL raised, the switching threshold is raised, so the part is no longer TTL compatible.

Best regards,
Christian

Hi Christian

Thank you for your answer. You made me look deeper in the datasheet. I was mislead by the specification "VL RESET Voltage <= 2.4" and the fact that VL=15V is allowed, so I was thinking that I could get away with VL=3.3V, but was unsure about the VIL/VIH trigger levels. A discussion with AI assured me that there was no problem with VL=3.3V on MAX335 etc. Also, today my colleague found that the specification says that VL,min is 4.5V, which I had overlooked. I have now changed VL to 5V and added a levelshifter for the 3.3V logic.

Again, thank you for your help!

Best Regards
Bent