The Pasmo card and Suica card are sold by different companies. However, they work the same way and can be used in the same places. They are for example comparable with Mastercard and Visa credit cards, which belong to different companies but can be used in the same way.
The only small difference is the location where you can give your card back and receive your deposit.If you would like to return your Pasmo card at the end of your trip, you can only return it within the Tokyo area. Head to a station of a non JR subway line (for instance : the Keihin or Keisei lines), or the stations at Narita or Haneda Airports. Your remaining balance and ¥500 deposit will be returned to you.If you want to return your Suica card at the end of your stay, you can only do this in the Tokyo region. In order to get a refund, go into any other JR East station. You will then be able to recover the 500 yen deposit.