The NEC ND3650A DVD burner was first spotted in May 2006 but seems to have been developed earlier already. Unlike most other drives, the 3650 and 3651 are attached via an S-ATA interface. The NEC ND3651 burner adds support for LabelFlash but both drives - together with the ND4650 and ND4651 - share the same hardware and only differ in firmware. However you should not try to simply flash a NEC 3651 firmware on a NEC 3650 drive or vice versa. This will NOT work.
Click here for detailed specifications of the NEC ND3650A and ND3651A.
The following firmwares are available for download here:
Overview on the used writing strategies