03541 September 12, 2012 Rev: E
EP5358LUI/EP5358HUI
©Enpirion 2012 all rights reserved, E&OE 9 www.enpirion.com
Detailed Description
Functional Overview
The EP5358xUI requires only 2 small MLCC
capacitors for a complete DC-DC converter
solution. The device integrates MOSFET
switches, PWM controller, Gate-drive,
compensation, and inductor into a tiny 2.5mm x
2.25mm x 1.1mm micro-QFN package.
Advanced package design, along with the high
level of integration, provides very low output
ripple and noise. The EP5358xUI uses voltage
mode control for high noise immunity and load
matching to advanced ≤90nm loads. A 3-pin
VID allows the user to choose from one of 8
output voltage settings. The EP5358xUI
comes with two VID output voltage ranges.
The EP5358HUI provides VOUT settings from
1.8V to 3.3V, the EP5358LUI provides VID
settings from 0.8V to 1.5V, and also has an
external resistor divider option to program
output setting over the 0.6V to VIN-0.25V
range. The EP5358xUI provides the industry’s
highest power density of any 600mA DCDC
converter solution.
The key enabler of this revolutionary
integration is Enpirion’s proprietary power
MOSFET technology. The advanced MOSFET
switches are implemented in deep-submicron
CMOS to supply very low switching loss at high
switching frequencies and to allow a high level
of integration. The semiconductor process
allows seem-less integration of all switching,
control, and compensation circuitry.
The proprietary magnetics design provides
high-density/high-value magnetics in a very
small footprint. Enpirion magnetics are
carefully matched to the control and
compensation circuitry yielding an optimal
solution with assured performance over the
entire operating range.
Protection features include under-voltage lock-
out (UVLO), over-current protection (OCP),
short circuit protection, and thermal overload
protection.
Integrated Inductor: Low-Noise Low-EMI
The EP5358xUI utilizes a proprietary low loss
integrated inductor. The integration of the
inductor greatly simplifies the power supply
design process. The inherent shielding and
compact construction of the integrated inductor
reduces the conducted and radiated noise that
can couple into the traces of the printed circuit
board. Further, the package layout is
optimized to reduce the electrical path length
for the high di/dT input AC ripple currents that
are a major source of radiated emissions from
DC-DC converters. The integrated inductor
provides the optimal solution to the complexity,
output ripple, and noise that plague low power
DCDC converter design.
Control Matched to sub 90nm Loads
The EP5358xUI utilizes an integrated type III
compensation network. Voltage mode control
is inherently impedance matched to the sub
90nm process technology that is used in
today’s advanced ICs. Voltage mode control
also provides a high degree of noise immunity
at light load currents so that low ripple and high
accuracy are maintained over the entire load
range. The very high switching frequency
allows for a very wide control loop bandwidth
and hence excellent transient performance.
Soft Start
Internal soft start circuits limit in-rush current
when the device starts up from a power down
condition or when the “ENABLE” pin is
asserted “high”. Digital control circuitry limits
the VOUT ramp rate to levels that are safe for
the Power MOSFETS and the integrated
inductor.
The EP5358HUI has a soft-start slew rate that
is twice that of the EP5358LUI.
When the EP5358LUI is configured in external
resistor divider mode, the device has a fixed
VOUT ramp time. Therefore, the ramp rate will
vary with the output voltage setting. Output
voltage ramp time is given in the Electrical
Characteristics Table.