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Enpirion® Power Datasheet
EN5394QI 9A PowerSoC
Voltage Mode Synchronous
Buck PWM DC-DC Converter
With Integrated Inductor
Description
Typical Application Circuit
The EN5394QI is a Power Supply on a Chip
(PwrSoC) DC to DC converter with integrated
inductor, PWM controller, MOSFETS, and
compensation providing the smallest possible
solution size in a 68 pin QFN module. The
switching frequency can be synchronized to an
external clock or other EN5394QIs with the
added capability of phasing multiple EN5394QIs
as desired. Other features include precision
ENABLE threshold, pre-bias monotonic start-up,
margining, and parallel operation.
EN5394QI is specifically designed to meet the
precise voltage and fast transient requirements
of present and future high-performance
applications such as set-top boxes/HD DVRs,
LAN/SAN adapter cards, audio/video equipment,
optical networking, multi-function printers, test
and measurement, embedded computing,
storage, and servers. Advanced circuit
techniques, ultra high switching frequency, and
very advanced, high-density, integrated circuit
and proprietary inductor technology deliver high-
quality, ultra compact, non-isolated DC-DC
conversion. Operating this converter requires
very few external components.
The Altera Enpirion integrated inductor solution
significantly helps to reduce noise. The complete
power converter solution enhances productivity
by offering greatly simplified board design, layout
and manufacturing requirements.
All Altera Enpirion products are RoHS compliant
and lead-free manufacturing environment
compatible.
VIN
47µF
15nF
PVIN VOUT
AVIN
ENABLE
PGND VFB
SS
OCP_ADJ
PGND
AGND
VOUT
2x47µF
Figure 1: Typical Application Schematic
Features
• Integrated Inductor, MOSFETS, Controller in
a 8 x 11 x 1.85mm package
• Wide input voltage range of 2.375V to 6.6V.
• > 30W continuous output power.
• High efficiency, up to 93%.
• Output voltage margining
• Monotonic output voltage ramp during start-
up with pre-biased loads.
• Precision Enable pin for accurate sequencing
of power converters and Power OK signal.
• Programmable soft-start time.
• Soft Shutdown.
• 4 MHz operating frequency with ability to
synchronize to an external system clock or
other EN5394’s.
• Programmable phase delays between
synchronized units to allow reduction of
input ripple.
• Master/slave configuration for paralleling
multiple EN5394’s for greater power output.
• Under Voltage Lockout, Over-current, Short
Circuit, and Thermal Protection
• RoHS compliant, MSL level 3, 260C reflow.
03738
1
October 11, 2013
www.altera.com/enpirion
Rev E
EN5394QI
Electrical Characteristics table. See Figures 6 be used advantageously for power supply
and 7 for an example of using phase delay.
sequencing using the precision Enable threshold.
Margining
Using MAR1 and MAR2 pins, the nominal output
voltage can be increased / decreased by 2.5, 5
or 10% for system compliance, reliability or other
tests. The POK threshold voltages scale with the
margined output voltages. The following table
provides the possible combinations:
MAR1 MAR2 Output Modulation
Float Float
0%
Low Low
-2.5%
High
Low
+2.5%
Low High
-5%
High High
+5%
Low Float
-10%
High Float
+10%
Float High
0%, Delay Bypass
Float Low
Reserved
Note: Low means tie to GND. High means tie to VIN
as shown in Figure 5.
As shown above, when MAR1 is floating, and
MAR2 is high, the device enters the delay
bypass mode. In this mode, the delay from the
internal clock or S_IN to S_OUT is almost
eliminated (see Electrical Characteristics table).
Soft-Start Operation
The SS pin in conjunction with a small external
capacitor between this pin and AGND provides
the soft start function to limit the in-rush current
during start-up. During start-up of the converter
the reference voltage to the error amplifier is
gradually increased to its final level as an internal
current source of typically 10uA charges the soft
start capacitor. The typical soft-start time for the
output to reach regulation voltage, from when
AVIN > VUVLO and ENABLE crosses its logic high
threshold, is given by:
TSS = (CSS * 65KΩ) ± 25%
where the soft-start time TSS is in seconds and
the soft-start capacitance CSS is in Farads.
Typically, around 15nF is recommended. The
soft-start capacitor should be between 4.7nF and
100nF. A proper choice of SS capacitance can
During a soft-start cycle, when the soft-start
capacitor voltage reaches 0.60V, the output has
reached its programmed regulation range. Note
that the soft-start current source will continue to
charge the SS capacitor beyond 0.6V. During
normal operation, the soft-start capacitor will
charge to a final value of ~1.5V.
Soft-Shutdown Operation
When the Enable signal is de-asserted, the soft-
start capacitor is discharged in a controlled
manner. Thus the output voltage ramps down
gradually. The internal circuits are kept active for
the duration of soft-shutdown, thereafter they are
deactivated.
Pre-Bias Operation
When EN_PB is asserted, the device will support
a monotonic output voltage ramp if the output
capacitor is charged to a pre-bias level.
Proprietary circuit ensures the output voltage
ramps monotonically from pre-bias voltage to the
programmed output voltage. Monotonic start-up
is guaranteed by design for pre-bias voltages
between 20% and 85% of the programmed
output voltage. This feature is not supported
when ENABLE is tied to VIN.
POK Operation
The POK signal indicates if the output voltage is
within a specified range. The POK signal is
asserted when the rising output voltage crosses
92% (nominal) of the programmed output
voltage. POK is de-asserted ~50us (256 clock
cycles) after the falling output voltage crosses
90% (nominal) of the programmed voltage. POK
is also de-asserted if the output voltage exceeds
120% of the programmed output. If the feedback
loop is broken, POK will remain de-asserted
(output < 92% of programmed value), and the
output voltage will equal the input voltage. If
however, there is a short across the PFET, and
the feedback is in place, POK will be de-asserted
as an over voltage condition. The power NFET is
also turned on, resulting in a large input supply
current. This in turn is expected to trip the OCP
03738
11
October 11, 2013
www.altera.com/enpirion
Rev E