LM22680EVAL National Semiconductor, LM22680EVAL Datasheet

BOARD EVAL FOR LM22680

LM22680EVAL

Manufacturer Part Number
LM22680EVAL
Description
BOARD EVAL FOR LM22680
Manufacturer
National Semiconductor
Series
PowerWise®r
Datasheet

Specifications of LM22680EVAL

Current - Output
500mA
Voltage - Output
3.3V
Voltage - Input
4.5 ~ 42V
Utilized Ic / Part
LM22680
Frequency - Switching
500kHz
Outputs And Type
1, Non-Isolated
Board Type
Fully Populated
Regulator Topology
Buck
Main Purpose
DC/DC, Step Down
Silicon Manufacturer
National
Silicon Core Number
LM22680
Kit Application Type
Power Management - Voltage Regulator
Application Sub Type
Step Down Voltage Regulator
Kit Contents
Board
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Power - Output
-

Available stocks

Company
Part Number
Manufacturer
Quantity
Price
Part Number:
LM22680EVAL/NOPB
Manufacturer:
National Semiconductor
Quantity:
135
© 2010 National Semiconductor Corporation
LM22680 Evaluation Board
Introduction
The LM22680 evaluation board is designed to demonstrate
the capabilities of the LM22680 switching regulator. The
LM22680 evaluation board schematic shown in
configured to provide an output voltage of 3.3V up to 2A load
current with an input voltage range of 4.5V to 42V. Due to the
low R
mum duty-cycle limitations, the minimum input voltage of 4.5V
will only provide a 3.3V output voltage for load currents up to
500 mA. For load currents higher than 500 mA, an input volt-
age of 5.5V or higher is required. The typical operating fre-
quency is 500 kHz. The evaluation board is designed to
operate at ambient temperatures up to 65°C, and at steady
state operating conditions.
DS(ON)
of the integrated N-channel MOSFET and maxi-
300832
FIGURE 1. Evaluation Board Schematic
Figure 1
is
National Semiconductor
Application Note 1911
Ricardo Capetillo
July 6, 2010
The performance of the evaluation board is as follows:
Input Range: 4.5V to 42V
Output Voltage: 3.3V
Output Current Range: 0A to 2A
Frequency of Operation: 500 kHz
Board Size: 1.5 X 1.5 inches
Package: PSOP-8
At low input voltages between 4.5V and 6V, a minimum load
of approximately 5 mA may be required to reach a regulated
3.3V output voltage. See the LM22680 datasheet for more
details.
To aid in the design and evaluation of DC/DC buck converter
solutions based on the LM22680 switching regulator, the
evaluation board can be re-configured for different output
voltages.
The evaluation board is designed to highlight applications
with a small solution size. This implies that there will be a
tradeoff with the area of heat dissipation available. If this eval-
uation board is operated continuously at a full 2A load, it will
get hot. For higher output voltages than the pre-adjusted
3.3V, the total output power as well as the total power con-
version losses will increase. It is recommended to use a fan
or other source of air flow when evaluating the board at full
2A load or at output voltages greater than 3.3V. Typical eval-
uation board performance and characteristics curves are
shown in
layout.
Test points are provided to enable easy connection and mon-
itoring of critical signals. When performing over load or short
circuit tests, refer to the current limit section of the LM22680
datasheet to determine if the circuit is in safe operating mode.
For more information about device function and electrical
characteristics, refer to the LM22680 datasheet.
Figure 2
through
Figure
5.
30083201
Figure 6
shows the PCB
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LM22680EVAL Summary of contents

Page 1

... For load currents higher than 500 mA, an input volt- age of 5.5V or higher is required. The typical operating fre- quency is 500 kHz. The evaluation board is designed to operate at ambient temperatures up to 65°C, and at steady state operating conditions. © 2010 National Semiconductor Corporation National Semiconductor Application Note 1911 Ricardo Capetillo July 6, 2010 The performance of the evaluation board is as follows: Input Range: 4 ...

Page 2

... Precision Enable The EN test point provided on the LM22680 evaluation board can be used to shut down the LM22680 when connecting this test point to ground. TABLE 1. LM22680EVAL Bill of Materials for VOUT = 3.3V, Designed for 2A output current Ref # Value C1 6.8 µF 50V ceramic C2 22 µ ...

Page 3

Performance Characteristics Unless otherwise specified 12V FIGURE 2. Start-Up Waveforms (Load Resistor = 1.1Ω) FIGURE 3. Operation 25°C. A 30083205 30083202 FIGURE 5. Overall Loop Gain and Phase (f 3 30083203 FIGURE 4. ...

Page 4

PCB Layout Diagram www.national.com FIGURE 6. Top Layer 4 30083206 ...

Page 5

5 www.national.com ...

Page 6

... For more National Semiconductor product information and proven design tools, visit the following Web sites at: www.national.com Products Amplifiers www.national.com/amplifiers Audio www.national.com/audio Clock and Timing www.national.com/timing Data Converters www.national.com/adc Interface www.national.com/interface LVDS www.national.com/lvds Power Management www.national.com/power Switching Regulators www.national.com/switchers LDOs www.national.com/ldo LED Lighting www ...

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