in reply to: Re: Re: where to get sym2c015? posted by KRUSHNA on 10 February 2006 at 06:14:16.
I would recommend to you if you are going to make a new design for a HART modem to design the board for two different type of chips, so that you can mount either the first or the second type. By this you will get rid of the single source or long delivery time problem which can happen with this special FSK-modem component.
Use as type 1 the components 20C15 (SMAR) or
A5191HRT (AMIS) and as type 2 the HT2012 (SMAR) or NCR 20C12. Both types are not pin compatible and also the external passive components are different, but you can make a PCB design so that you can mount either the first or the second type. Last but not least I always like to mention that the HART FSK technology is very old fashioned, coming from long time ago when 1200 bits per second was considered as fast for telephone modems etc. I you really want to go ahead for the future you should think about modern field busses instead of HART devices, where the data transmission is more or less just a electronic screwdriver, but not suitable for fast measurement data transmission. But oldies are goldies, and so this technology is still allive ;)