Miller must attend a 16-week domestic violence counseling course as part of his sentence, prosecutors said,
There is also a protective order in effect, barring Miller from any contact with the victim, pending sentencing.
Prosecutors said Miller was expected to be sentenced in about six months after he has completed the program.
"We are satisfied that Mr. Miller is taking steps to address his underlying anger issues," prosecutor Tyrone Wilson said. "He will hear in his mandated class that domestic violence is unacceptable no matter what the degree or circumstance."
Investigators said that on the night of March 5 the victim and Miller were arguing in a parking garage at the Rivermark Hyatt House in Santa Clara.
Miller grabbed her cell phone and threw it against a wall, smashing it.
Miller's girlfriend, who refused medical attention, did not sustain any visible injuries or have any complaint of pain. She denied that there had been any physical contact during the incident.
An independent witness, who was sitting at a nearby bagel shop, told police she saw the suspect and victim exit the garage on foot as they argued.
Investigators said the witness saw the suspect throw the phone. The witness then allowed the victim to use her phone to call police.