• Input Voltage: 1.1 V to 5.5 V
• Wide VBIAS Supply Operating Range: 3 V to 5.5 V
• Standard VOUT Values: 0.8 V and 1.2 V
• Stable With 10-µF Ceramic Capacitors
• Dropout Voltage of 240 mV (typical) at 3-A Load Current
• Programmable Soft-Start Time
• Precision Output Voltage Across All Line and Load Conditions:
  • ±1% VOUT for TJ = 25°C
  • ±2% VOUT for 0°C ≤ TJ ≤ +125°C
  • ±3% VOUT for –40°C ≤ TJ ≤ +125°C
• Overtemperature and Overcurrent Protection
• Operating Temperature Range: −40°C to +125°C

• ASIC Power Supplies In:
  • Desktops, Notebooks, Graphics Cards, and Servers
  • Gaming Set Top Boxes, Printers, and Copiers
• Server Core and I/O Supplies
• DSP and FPGA Power Supplies
• SMPS Post-Regulator

The LP38859 is a high-current, fast-response regulator which can maintain output voltage regulation with extremely low input to output voltage drop. Fabricated on a CMOS process, the device operates from two input voltages: VBIAS provides voltage to drive the gate of the N-MOS power transistor, while VIN is the input voltage which supplies power to the load. The use of an external bias rail allows the part to operate from ultra-low VIN voltages. Unlike bipolar regulators, the CMOS architecture consumes extremely low quiescent current at any output load current. The use of an N-MOS power transistor results in wide bandwidth, yet minimum external capacitance is required to maintain loop stability.

The fast transient response of this device makes it suitable for use in powering DSP microcontroller core voltages and switch-mode power-supply post-regulators. The LP38859 is available in 5-pin TO-220 and DDPAK/TO-263 packages.