It takes serious design work to make them small, but it can be done.
![](http://upload.wikimedia.org/wikipedia/commons/thumb/4/43/DavyCrockettBomb.jpg/200px-)
This one weighed at under 100 pounds. Sub-kiloton yield. It's name was the Davy Crockett.
Did you ever see what happened when they tested it? IIRC the jeep that launched it got blown over by the shock wave. It wasn’t exactly long range.