The MAX8855 high-efficiency, dual step-down regulator
is capable of delivering up to 5A at each output. The
device operates from a 2.35V to 3.6V supply, and pro-
vides output voltages from 0.6V to 0.9 x VIN, making it
ideal for on-board point-of-load applications. Total output
error is less than ±1% over load, line, and temperature.
The MAX8855 operates in PWM mode with a switching
frequency ranging from 0.5MHz to 2MHz, set by an
external resistor. It can also be synchronized to an
external clock in the same frequency range. Two inter-
nal switching regulators operate 180° out-of-phase to
reduce the input ripple current, and consequently
reduce the required input capacitance. The high
operating frequency minimizes the size of external
components. High efficiency, internal dual-nMOS
design keeps the board cool under heavy loads. The
voltage-mode control architecture and the high-band-
width (> 15MHz typ) voltage-error amplifier allow a type
III compensation scheme to be utilized to achieve fast
response under both line and load transients, and also
allow for ceramic output capacitors.
Programmable soft-start reduces input inrush current.
Two enable inputs allow the turning on/off of each out-
put individually, resulting in great flexibility for system-
level designs. A reference input is provided to facilitate
output-voltage tracking applications. The MAX8855 is
available in a 32-pin thin QFN (5mm x 5mm) package
with 0.8mm max height.
Applications
ASIC/CPU/DSP Power Supplies
DDR Power Supplies
Set-Top Box Power Supplies
Printer Power Supplies
Network Power Supplies