BD3539NUX is a termination regulator that complies with JEDEC requirements for DDR1-SDRAM, DDR2-SDRAM, and DDR3-SDRAM. This linear power supply uses a built-in N-channel MOSFET and high-speed OP-AMPS specially designed to provide excellent transient response. It has a sink/source current capability of up to 1A and has a power supply bias requirement of 3.3 V (for DDR2 and DDR3) and 5.0 V (for DDR1, DDR2, and DDR3) for driving the N-channel MOSFET. By employing an independent reference voltage input (VDDQ) and a feedback pin (VTTS), this termination regulator provides excellent output voltage accuracy and load regulation as required by JEDEC standards. Additionally, BD3539 has a reference power supply output (VREF)for DDR-SDRAM or for memory controllers. Unlike the VTT output that goes to "Hi-Z" state, the VREF output is kept unchanged when EN input is changed to "Low", making this IC suitable for DDR-SDRAM under "Self Refresh" state.