Ritchie, 26, said interest from a club Newcastle’s size was something “he wanted to pursue” as they seek an immediate return to the Premier League.
“It’s going to be a really exciting season and something I really want to be part of,” he told BBC Radio Solent.
Ritchie, part of two promotion-winning squads during his three seasons at Bournemouth, revealed he was “caught off guard” by initial interest from Rafa Benitez’s side.
“As soon as I heard, it was something that excited me,” he said. “The size of the football club, the manager and when you look a bit deeper, the squad we’ve got.”
A wanted man on two fronts
Time away with Scotland prevented Ritchie negotiating a new deal at Bournemouth before Newcastle’s offer emerged.
“I’m sure if the offer (of a new contract) had come at a different time, or if I’d come back from Scotland duty with no interest from other clubs, there would’ve been some sort of agreement,” Ritchie admitted.
An offer for both him and team-mate Callum Wilson from West Ham in May failed to gather momentum as he focused on a second top-flight season at the Cherries.
“I think it was flattering,” Ritchie said. “But, nothing came of it.
“I was working hard as if I was coming back to Bournemouth and had nothing else on my mind.
“But when things do come up and you hear of interest from other clubs, you have to deal with it and that’s football.
“When a club like Newcastle is interested, I wanted to pursue it,” he added. “I’m delighted to be here, it’s a fantastic club.”