Part numbers:
ISP281B
Current Transfer Ratio (Min) 130% @ 5mA
Current Transfer Ratio (Max) 260% @ 5mA 600% @ 5mA
ISP281
Current Transfer Ratio (Min), 50% @ 5mA
Current Transfer Ratio (Max), 600% @ 5mA
Screen shot from data sheet.
Data sheet link below:
dd93256-030620.pdf