In order to become eligible to receive payments for your AdSense account, all publishers are required to enter a Personal Identification Number (PIN). PINs are necessary to verify the accuracy of your contact information and to help ensure that you can receive your payments.
There are several reasons why you might not have received your Personal Identification Number yet.
- Your account is not on PIN hold.
You will be required to verify your PIN only after your account balance reaches verification threshold (€10 or $10). If you do not see a hold displayed at the top of Overview page, then it means that your account is not on PIN hold yet.
- A PIN might not have been sent to you.
You have to wait for a week after your account balance reached verification threshold for a PIN to be generated and mailed to you.
- You haven't waited for 4 weeks after your last PIN was generated.
PINs often take up to 4 weeks to reach you by mail, it may take longer depending on your location.
If you have not received your PIN after 4 weeks, you can request a new one. To find the date when you will be able to request a new PIN by logging in to your account and viewing the Account Settings page under the Home tab.
- Your payment address is not valid.
Take a moment to review your payment address, and make updates to your address if necessary.
How to requesting a new PIN
If you haven't received your PIN, or if it has been lost, you can request two more PINs. To make sure it has enough time to reach you, you'll need to wait 3 weeks after your last PIN was mailed before requesting a new one.
To request a new PIN:
- Sign in to your account.
- On the Home tab, visit the Account settings page.
- Click the 'Verify address' link.
- At the bottom of the page, click Request new PIN.
What if I do not receive my PIN?
If you do not receive your first PIN, you can request 2 replacement PINs. If you have requested your maximum of 3 PINs and have not received any of them within 90 days, then sign in to your account. You'll see a notice on the Reports Overview page with further instructions.
I hope this helps...
Source: Adsense Help