* ParkerVision falls as much as 76 percent, plans appeal
* Judge says not enough evidence of patent infringement
(Adds Qualcomm statement, updated share prices)
June 23 (Reuters) - A U.S. federal judge overturned a jury verdict that had required chipmaker Qualcomm Inc to pay ParkerVision Inc $173 million for infringing patents for technology used in smartphones.
Shares of ParkerVision, which designs wireless chips, plunged as much as 76 percent on Monday.
In a decision dated June 20, U.S. District Judge Roy Dalton in Jacksonville, Florida, said expert testimony offered by a key ParkerVision witness provided "an insufficient evidentiary basis" for a finding of patent infringement. He also said Qualcomm deserves a new trial if an appeals court disagrees.
"While the court is loath to overturn the jury's verdict, on this record, it is the court's only choice," Dalton wrote. He also rejected Qualcomm's request to rule the patents invalid.
ParkerVision Chief Executive Officer Jeffrey Parker said in a statement that he was "obviously disappointed" by the outcome, and that the Jacksonville-based company would appeal.
"We are very pleased," Alex Rogers, head of litigation at San Diego-based Qualcomm, said in a statement. "Qualcomm simply does not use the techniques claimed in ParkerVision's patents."
In court papers, ParkerVision had charged that Qualcomm in 2006 began infringing its patents for radio signal converion technology, incorporating it in products sold for use in mobile devices such as smartphones.
ParkerVision claimed it had sought without success to license the technology to Qualcomm in the late 1990s, only to learn more than a decade later that the rival chipmaker had begun using it.
The $173 million award had been seen as a disappointment for ParkerVision, which had sought more than twice as much.
Jurors also rejected ParkerVision's argument that Qualcomm's alleged infringement was willful, which could have resulted in triple damages.
ParkerVision also has a separate lawsuit against Qualcomm and HTC Corp over other patents that relate to radio frequency transmitters.
In afternoon trading on the Nasdaq, ParkerVision shares were down $2.92, or 58.3 percent, at $2.09, after earlier falling to $1.21. Qualcomm was down 6 cents at $79.80.
The case is ParkerVision Inc v Qualcomm Inc, U.S. District Court, Middle District of Florida, No. 11-00719.
(Reporting by Jonathan Stempel in New York; Editing by Lisa Von Ahn and David Gregorio)