C3225X5R0J476M,C3225X5R1C226M

Part No.:
C3225X5R0J476M,C3225X5R1C226M
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Description:
LMZ1050xEXT Evaluation Board
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1354 K
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12 Pages
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NSC [ NATIONAL SEMICONDUCTOR ]
PCB Prototype

July 19, 2018:

C328

CCM1370-ND

CDR33BX104AKYS

CER0034A

CHR3394-QEG

CHT3091AQAG_10

CL-195

CLD-AP90

CM105B105K16A

CMC7106Y

CR1J10YTTE

CRD4205-1

PCB Datasheet:1PCB Datasheet:1
LMZ1050xEXT Evaluation Board
LMZ1050xEXT Evaluation
Board
National Semiconductor
Application Note 2074
Yang Zhang
August 16, 2010
Introduction
The LMZ1050xEXT SIMPLE SWITCHER® power module is
a complete, easy-to-use DC-DC solution capable of driving
up to 3A, 4A, or 5A load with exceptional power conversion
efficiency, output voltage accuracy, line and load regulation.
The LMZ1050xEXT is available in an innovative package that
enhances thermal performance and allows for hand or ma-
chine soldering.
The LMZ1050xEXT can accept an input voltage rail between
2.95V and 5.5V and deliver an adjustable and highly accurate
output voltage as low as 0.8V. One megahertz fixed frequen-
cy PWM switching provides a predictable EMI characteristic.
Two external compensation components can be adjusted to
set the fastest response time, while allowing the option to use
ceramic and/or electrolytic output capacitors. Externally pro-
grammable soft-start capacitor facilitates controlled startup.
The LMZ1050xEXT is a reliable and robust solution with the
following features: lossless cycle-by-cycle peak current limit
to protect for over current or short-circuit fault, thermal shut-
down, input under-voltage lock-out, and pre-biased startup.
Evaluation Board Design Concept
The evaluation board is designed to demonstrate low con-
ducted noise on the input and output lines, as seen in
Figure
11
and
Figure 14.
Four input capacitors (C
in1
- C
in4
) and three
output capacitors (C
o1
- C
o3
) are populated for this purpose.
All the input and output filter capacitors are not necessary to
comply with radiation standards. For a circuit example that
passes radiated emissions standards (EN55022, class B)
please refer to
Figure 19.
Additionally, C
in5
is present to re-
duce the resonance of the input line produced by the induc-
tance and resistance in the cables connecting the bench
power supply to the evaluation board and the input capacitors.
Additional Component Footprints
When the tracking feature of the LMZ1050xEXT is used, re-
move the soft-start capacitor C
SS
and use a resistor divider
on designators R
trkb
and R
trkt
. The ground and V
trk
post have
been provided for easy connection.
The LMZ1050xEXT eval board incorporates a precision en-
able circuit which is pulled high by a 100 kΩ pull up resistor
to VIN. This allows the user to pull low on the enable pin to
ground. The top enable resistor is R
ent
and the bottom enable
resistor is R
enb
. Refer to the Design Guideline and Operating
Description section of the LMZ1050xEXT data sheet for de-
tailed design implementation.
Select FPGAs specify input inrush currents for particular pow-
er-up sequences and others require sequencing rails to avoid
start-up or latch-up problems. To prevent early turn-on of the
LMZ1050xEXT in systems with multiple power rails, precision
enable and tracking are useful as the main input voltage rail
rises at power-up.
Board Specifications
V
IN
= 2.95V to 5.5V
V
OUT
= 2.5V (default output voltage setting, refer to
Table
2
for other output settings)
±2.5% feedback voltage accuracy at 2.5V output
(Including line and load regulation from T
J
= -55°C to
125°C)
±1.63% feedback voltage accuracy over temperature
I
OUT
= 0A to 3A, 4A, and 5A
θ
JA
= 20°C/W,
θ
JC
= 1.9°C/W
Designed on four layers, the top and bottom layers are
1oz. copper and the two inner layers are 1/2 oz. copper
weight
Measures 2.25 in. x 2.25 in. (5.8 cm x 5.8 cm) and is 62mil
(.062”) thick on a FR4 laminate
AN-2074
© 2010 National Semiconductor Corporation
301280
www.national.com