PN53x with emulate nfc
why is PN53x chipset can't do it? what is so special on this iso?


ISO14443-B is the only standard among the NFC chips that use BPSK encoding. Also ISO14443-B is not used much in practice. Maybe NXP decided that it's not worth implementing a mode that only a few people would use.


  i looking for another nfc reader that can emulate this iso


As far as I know all modern NFC controllers aimed for the mobile market can do this. The need for B card-mode came with the idea of having your credit-card in your mobile phone.


  why many of nfc reader based on this chipset?


The PN53x chips are cheap and very easy to integrate. You can just hook it up to a usb-serial converter (for the very common PN532) or directly connect it to USB (PN533). That's all you need for a USB based NFC reader.

The newer chips have a more complex host interface and require an additional micro-controller to act as a bridge between USB and the reader-chip itself. Their advantage is a much tighter control over the timing. This is very important in the credit-card reader market.