Hello,

I am in need of a dual railing H-Bridge IC.  By this, I mean an H-bridge =
IC that allows me to set a high railing at 10V, a low railing at -10V, =
and then use two CMOS signal to control the polarity across my sensor (a =
cermain ultrasonic transducer).  The idea being I can then switch the =
CMOS signal at each side of the H-bridge to create a 40kHz 20Vp-p square =
wave.  Does such an IC exist?  I have not heard of one and my search =
turned up nothing.

If I am going to build this circuit with transistors can someone suggest =
a transistor that can handle these railings, has a low Vce(sat) rating, =
and can switch quickly (I want to be as close as possible to a 20Vp-p =
square wave). =20

An alternative to transistors would be to use two op-amps set as =
comparators with a reference voltage of 2.5V.   Then, two CMOS signal =
could saturate the op. amps to +10V or -10V as desired.  Hence, can =
anyone suggest a dual comparator IC that can come close to the railings =
(I think this is refered to as a railing-to-railing op. amp.) and has a =
fast switching rate (again, to come as close as possible to a square =
wave).

Does anyone have an alternative suggestion?  Note, that I need to be =
able to 'turn off' the circuit so there is zero volts across the =
transducer (apparently, a DC voltage across it causes 'wear and tear').  =
Both the transistor H-bridge and comparator circuits allow this by =
setting the CMOS signals to the same state.

Regards,
Donovan Parks

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