I just talked to the TI Rep and they say that the TL853 has been
discontinued and that the TL851 and TL852 are not recommended for new
designs.

>Hi Richard,
>
>        I just got a data book from TI that has three IC that they
>produce specifically for sonar ranging control.  As this is also one my
>interest (great for robots), I am going to look into to using them and I
>let you know.
>
>Device #'s
>
>TL851
>TL852
>TL853
>
>        They were in the Linear Circuits Data Book, Vol #3, available
>from your friendly TI Rep 214-644-5580.
>
>Ben,
>blw2@cec.wustl.edu

John Bean

Advanced Telemetry Systems
jrb@gate.net