Can someone suggest a high voltage line driver IC? I have requirements for two seperate uses.
1.) High voltage input. The IC needs to receive 0-30V digital input voltages and output 5V logic levels. However, I still want the driver to work if the input voltage levels are only 0-3.3V.2.) High voltage output. The IC needs to receive 5V digital input voltages and output 30V digital equivilents.
Thanks, David
See attached. Use 5V power supply instead of 30V.
See attached.
For the 1) application get your hands on the old style RS232 receiver of the 1488/1489 set. The DS1489s inputs work up to +/- 30V.
For the 2) driver take a look at the SN75452 type parts. These can handle up to 30V on the outputs. (Both Digikey and Jameco have them in stock).
These are older parts so I would encourage you to look at other lower voltage transmission techniques if you are intending to go into production with the thing you are trying to design/build.
- mkaras
Do you need the receiver to automatically center its threshold right in the middle?
How far does the signal have to go? At what data rate? Does it have to be short-circuit protected? What about static protection?
Your basic LM339 comparator IIRC can be used for both jobs if the requirements arent too tough.
Interesting idea. I'll have to investigate.
I've thought about open collector solutions, but I was hoping for push pull.
I do intend to enter production. It is an industrial control application that needs to interface with PLC's. I'm no PLC expert, but I believe they typically have 24V digital I/O. That is why I need the high voltage.
However, I also want the device to be usefull on a lab bench where 3.3V logic is prominent. That is why I need the large range of logic voltages.
Thanks, David
This would be a great feature, but not absolutely required. It would be acceptable for the vIL_MAX and vIH_MIN to remain constant as long as they worked from 3.3V logic all the way up to 24V logic.
This is an industrial control product that will interface to PLC's which typically operate at 24V. The transmission distance can become very long. Data rates will be slow. Maybe 100ns to 200ns risetimes. Short circuit protection is very desireable as well as at least 2KV static protection.
That is a very good suggestion. That may be exactly what what I need. What is a typical switching time for a comparator that is saturated at the rail?
Thanks, David
On Fri, 22 Sep 2006 22:03:54 -0400, David Gave us:
There is at least one problem with what you need. To rise to 30 Volts can be said to be easy. To do so with digital data, a factor known as slew rate weighs in. You won't be able to go very fast before the slew rate issues corrupt the data, limiting the rate you can pass data at. Are such chips even around?
It is sort of akin to "floating" ones valves out from revving an engine to high for the weak valve springs. Motor can only turn so fast.
Whoa, Nelly! Sending 100nsec risetime signals any distance is going to require using differential twisted-pair or coax. For the twisted-pair you'll need some strong differential drivers, for the coax some 50 or 75 ohm drivers. The wire type you choose will determine the exact driver you'll need. See the "interface" section of IC's at
Well the 339 can do 30 volts output, OR 50 ohms, but not both at once.
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