LM3475EVAL National Semiconductor, LM3475EVAL Datasheet
LM3475EVAL
Manufacturer Part Number
LM3475EVAL
Description
BOARD EVALUATION LM3475
Manufacturer
National Semiconductor
Specifications of LM3475EVAL
Main Purpose
DC/DC, Step Down
Outputs And Type
1, Non-Isolated
Voltage - Output
2.5V
Current - Output
2A
Voltage - Input
2.7 ~ 10V
Regulator Topology
Buck
Board Type
Fully Populated
Utilized Ic / Part
LM3475
Lead Free Status / RoHS Status
Not applicable / Not applicable
Power - Output
-
Frequency - Switching
-
© 2005 National Semiconductor Corporation
LM3475 Evaluation Board
Introduction
The LM3475 evaluation board is provided as a tool for
developing DC/DC converters based on the LM3475 IC. As
shown in Figure 1, the evaluation board is configured to
provide an output of 2.5V at up to 2A from an input up to 10V.
The corresponding bill of material is given in Table 1. Typical
efficiencies are shown in Figure 2 and Figure 3. Figure 4 and
Figure 5 show the board layout.
To aid in the design and evaluation of dc/dc buck converters
based on the LM3475 controller, the LM3475 Evaluation
Board can be easily re-configured for different output volt-
ages.
Setting Vout
Vout can be set using R
equation:
FB1
, as shown in the following
AN201523
FIGURE 1. Full Demo Board Schematic
National Semiconductor
Application Note 1381
Wei Gu
May 2005
Where V
Refer to the datasheet before changing any component
values, since additional design adjustments may be re-
quired.
Optional Components
A feed-forward capacitor C
will increase operating frequency. However, the speed up
effect decreases with lower output voltage and is negligible
below 1.6V output.
A zero Ohm is used to pull up the EN pin for always on
operation. The enable pin can be pulled low at the EN post to
shutdown the device. If this resistor is removed, any analog
level signal can be used to enable and disable the device.
FB
is 0.8V typically.
V
OUT
= V
FB
x (R
FF
FB1
is placed on the board, which
+ R
FB2
) / R
20152301
FB2
www.national.com
Related parts for LM3475EVAL
Image
Part Number
Description
Manufacturer
Datasheet
Request
R
Part Number:
Description:
Precision Fahrenheit Temperature Sensors
Manufacturer:
National Semiconductor
Part Number:
Description:
National Semiconductor [8-Bit D/A Converter]
Manufacturer:
National Semiconductor
Datasheet:
Part Number:
Description:
National Semiconductor [Media Coprocessor]
Manufacturer:
National Semiconductor
Datasheet:
Part Number:
Description:
Digitally Controlled Tone and Volume Circuit with Stereo Audio Power Amplifier, Microphone Preamp Stage and National 3D Sound
Manufacturer:
National Semiconductor
Datasheet:
Part Number:
Description:
Digitally Controlled Tone and Volume Circuit with Stereo Audio Power Amplifier, Microphone Preamp Stage and National 3D Sound
Manufacturer:
National Semiconductor
Datasheet:
Part Number:
Description:
AC97 Rev 2 Codec with Sample Rate Conversion and National 3D Sound
Manufacturer:
National Semiconductor
Part Number:
Description:
Manufacturer:
National Semiconductor
Datasheet:
Part Number:
Description:
Manufacturer:
National Semiconductor
Datasheet:
Part Number:
Description:
General Purpose, Low Voltage, Low Power, Rail-to-Rail Output Operational Amplifiers
Manufacturer:
National Semiconductor
Datasheet:
Part Number:
Description:
8-bit 20 MSPS flash A/D converter.
Manufacturer:
National Semiconductor
Datasheet:
Part Number:
Description:
Low Noise Quad Operational Amplifier
Manufacturer:
National Semiconductor
Datasheet:
Part Number:
Description:
Quad Differential Line Receivers
Manufacturer:
National Semiconductor
Datasheet:
Part Number:
Description:
Quad High Speed Trapezoidal? Bus Transceiver
Manufacturer:
National Semiconductor
Datasheet:
Part Number:
Description:
Dual Line Receiver
Manufacturer:
National Semiconductor
Datasheet:
LM3475EVAL Summary of contents
Page 1
... LM3475 controller, the LM3475 Evaluation Board can be easily re-configured for different output volt- ages. Setting Vout Vout can be set using shown in the following FB1 equation: © 2005 National Semiconductor Corporation National Semiconductor Application Note 1381 Wei Gu May 2005 V OUT Where ...
Page 2
Designator CIN COUT CFF RFB2 RFB1 R2 www.national.com 20152302 FIGURE 2. Efficiency vs Output Current (Vin = 5V) 20152303 FIGURE 3. Efficiency vs Input Voltage (Iout = 2A) TABLE 1. Bill of Materials Part Description 10 µF ...
Page 3
... BANNED SUBSTANCE COMPLIANCE National Semiconductor manufactures products and uses packing materials that meet the provisions of the Customer Products Stewardship Specification (CSP-9-111C2) and the Banned Substances and Materials of Interest Specification (CSP-9-111S2) and contain no ‘‘Banned Substances’’ as defined in CSP-9-111S2. ...