Phone calls are one of those things you have to play by ear. Every girl is different and you have to tailor it to the situation. Generally I don't talk to girls on the phone. If I need to plan something, I do it via text. They really don't call me either but rather text "how was your day, what are you doing, I can't wait to see you, etc etc", to which I reply eventually. But in general:
1) Don't call a girl "just to chat". You're a man. You're busy and you have more important things to do than waste time on the phone. If she brings it up, tell her like it is - you're busy (even if you're not) and you'd rather see her in person than talk on the phone.
2) If something is wrong or you need to find out something that would be stupid to do via text (like get directions or discuss something that would take a buttload of typing), go ahead and call her.
3) There are other circumstances where calling is perfectly fine. For example: you've been dating a girl and she or you are away on vacation. You haven't seen each other in a few days and haven't been texting much. Then it's ok to just call and ask her how her day is, tell her you've been thinking about her, and you look forward to seeing her again when you/she gets back. 5 mins is a good rule.