en5311qi-e Enpirion, en5311qi-e Datasheet - Page 10

• Manufacturer Part Number: en5311qi-e
• Description: 1a Synchronous Buck Regulator With Integrated Inductor
• Manufacturer: Enpirion

The output capacitance requirement is a
minimum of 10uF.
designed to be stable with up to 60uF of total
output capacitance next to the output pins of
the device without requiring modification to the
compensation network. V
at the last output filter capacitor next to the
device. Capacitance above the 10uF minimum
should be added if the transient performance is
not sufficient using the 10uF.
recommends a low ESR MLCC type capacitor
be used.
Additional bulk capacitance for decoupling and
bypass can be placed at the load as long as
there is sufficient separation between the V
Sense point and the bulk capacitance.
separation provides an inductance that isolates
the control loop from the bulk capacitance.
LAYOUT CONSIDERATIONS*
*Optimized PCB Layout file downloadable from the Enpirion Website to assure first pass design success.
Recommendation 1: Input and output filter capacitors should be placed on the same side of the
PCB, and as close to the EN5311QI package as possible. They should be connected to the device
with very short and wide traces. Do not use thermal reliefs or spokes when connecting the capacitor
pads to the respective nodes. The +V and GND traces between the capacitors and the EN5311QI
should be as close to each other as possible so that the gap between the two nodes is minimized,
even under the capacitors.
Recommendation 2: DO NOT connect GND pins 3 and 4 together. Pin 3 should be used for the
Input capacitor local ground and pin 4 should be used for the output capacitor ground. The ground
pad for the input and output filter capacitors should be isolated ground islands and should be
connected to system ground as indicated in recommendation 3 and recommendation 5.
©Enpirion 2009 all rights reserved, E&OE
03799
1. For V
Cin
Murata
Panasonic
Taiyo Yuden
Manufacturer
IN
≤ 5.5V
GRM219R61A475KE19D
GRM319R61A475KA01D
GRM31MR60J475KA01L
GRM219R60J475KE01D
LMK212BJ475KG-T
LMK316BJ475KD-T
JMK212BJ475KD-T
ECJ-2FB1A475K
ECJ-3YB1A475K
ECJ-3YB0J475K
ECJ-2FB0J475K
Part #
The control loop is
OUT
Value
4.7uF
4.7uF
4.7uF
4.7uF
4.7uF
4.7uF
4.7uF
4.7uF
4.7uF
4.7uF
4.7uF
has to be sensed
WVDC
6.3V
6.3V
6.3V
10V
10V
10V
10V
10V
10V
10V
10V
1
1
1
Enpirion
Case Size
0805
1206
0805
1206
0805
1206
0805
1206
0805
1206
0805
The
OUT
11/24/2009
10
Cout
Manufacturer
Taiyo Yuden
Panasonic
Excess total capacitance on the output (Output
Filter + Bulk) can cause an over-current
condition at startup. Refer to the section on
Soft-Start for the maximum total capacitance
on the output.
The output capacitor must use a X5R or X7R
or equivalent dielectric formulation.
equivalent
capacitance
temperature and are not suitable for switch-
mode DC-DC converter input and output filter
applications.
Power-Up Sequencing
During power-up, ENABLE should not be
asserted before VIN. Tying these pins together
meets these requirements.
Murata
GRM219R60J106KE19D
GRM319R60J106KE01D
JMK212BJ106KD-T
JMK316BJ106KF-T
ECJ-2FB0J106K
ECJ-3YB0J106K
Part #
dielectric
with
frequency,
Value
10uF
10uF
10uF
10uF
10uF
10uF
formulations
www.enpirion.com
WVDC
6.3V
6.3V
6.3V
6.3V
6.3V
6.3V
bias,
EN5311QI
Case Size
0805
1206
0805
1206
0805
1206
Y5V or
lose
Rev:B
and