EN6347QI3 ENPIRION [Enpirion, Inc.], EN6347QI3 Datasheet - Page 12

• Manufacturer Part Number: EN6347QI3
• Description: 4A Voltage Mode Synchronous Buck PWM DC-DC Converter with Integrated Inductor
• Manufacturer: ENPIRION [Enpirion, Inc.]

Typical PWM Ripple Voltages
1 x 47 µF
47 µF + 10 µF
* Note: 20 MHz BW limit
Recommended Output Capacitors
47µF, 6.3V, 20%
X5R, 1206
(1 or 2 capacitors needed)
10µF, 10V, 10%
X5R, 1206
(Optional 1 capacitor in
parallel with 47µF above)
For best LLM performance, we recommend
using just 2x47uF capacitors mentioned in the
above table, and no 10uF capacitor.
The V
last output filter capacitor right next to the
device. Additional bulk output capacitance
Thermal Considerations
The Enpirion EN6347QI DC-DC converter is
packaged in a 7x4x1.85mm 38-pin QFN
package. The QFN package is constructed
with copper lead frames that have exposed
thermal pads. The recommended maximum
junction temperature for continuous operation
is 125°C. Continuous operation above 125°C
will reduce long-term reliability. The device has
a thermal overload protection circuit designed
to shut it off at a junction temperature specified
in the Electrical Characteristics Table.
The silicon is mounted on a copper thermal
pad that is exposed at the bottom of the
package. The thermal resistance from the
silicon to the exposed thermal pad is very low.
In order to take advantage of this low
resistance, the exposed thermal pad on the
package should be soldered directly on to a
copper ground pad on the printed circuit board
(PCB). The PCB then acts as a heat sink. In
order for the PCB to be an effective heat sink,
the device thermal pad should be coupled to
copper ground planes or special heat sink
structures designed into the PCB (refer to the
Layout Recommendations section).
¤Enpirion 2011 all rights reserved, E&OE
Output Capacitor
Configuration
05991
Description
OUT
sense point should be just after the
Typical Output Ripple (mVp-p)
Murata
Taiyo
Yuden
Murata
Taiyo
Yuden
(as measured on EN6347QI
MFG
Evaluation Board)*
GRM31CR60J476ME19L
JMK316BJ476ML-T
GRM31CR71A106KA01L
LMK316BJ226ML-T
25
15
P/N
10/04/2011
12
beyond the above recommendations can be
used on the output node of the EN6347QI as
long as the bulk capacitors are far enough from
the V
interfere with the control loop operation.
In
compensation or output filter capacitance may
be required to optimize device performance
such as transient response, ripple, or hold-up
time. The EN6347QI provides the capability to
modify the control loop response to allow for
customization for such applications. For more
information,
Engineering support.
Power-Up Sequencing
During power-up, ENABLE should not be
asserted before PVIN, and PVIN should not be
asserted before AVIN. Tying all three pins
together meets these requirements.
The junction temperature, T
the ambient temperature, T
dissipation, PD, and the device junction-to-
ambient thermal resistance,
follows:
The junction temperature, T
expressed in terms of the device case
temperature, T
case thermal resistance,
follows:
The device case temperature, T
temperature at the center of the exposed
thermal pad at the bottom of the package.
The device junction-to-ambient and junction-to-
case thermal resistances,
shown in the Thermal Characteristics Table.
The
package design. The
and the user’s system design parameters that
include the thermal effectiveness of the
customer PCB and airflow.
some
JC
OUT
is a function of the device and the QFN
sense point such that they don’t
T
T
cases
contact
J
J
C
= T
, and the device junction-to-
= T
C
A
+ (P
+ (P
modifications
Enpirion
JA
D
D
is a function of
www.enpirion.com
A
J
) (
) (
, is calculated from
, the device power
JC
JA
J
JA
, can also be
JC
JA
)
)
and
in °C/W, as
in °C/W, as
EN6347QI
Applications
C
, is the
to
JC
, are
Rev: B
the
JC