MPS MP2105DJ

EV2105DJ-00A
800mA Synchronous Buck
Step-Down Converter
Monolithic Power Systems
INITIAL RELEASE
GENERAL DESCRIPTION
FEATURES
The EV2105 evaluation board is designed for
low dropout step down converter applications. It
implements the MP2105 1MHz Fixed
Frequency, Current Mode, PWM step-down
converter. The device integrates a main switch
and a synchronous rectifier for high efficiency
without an external Schottky diode. It is ideal for
powering portable equipments that runs from a
single cell Lithium-Ion (Li+) Battery. It can
supply 800mA of load current from a 2.5V to 6V
input voltage. The output voltage can be
regulated as low as 0.6V. In 100% Duty Cycle
Dropout operation, it works with minimum input
voltage as low as output voltage.
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ELECTRICAL SPECIFICATION
Parameter
Input Voltage Range
Output Voltage
Load Max
Symbol
Value
Units
VIN
VOUT
IOUT
2.5 to 6.0
1.8
800
V
V
mA
High Efficiency: Up to 95%
800mA Available Load Current
2.5V to 6V Input Voltage Range
Output Voltage as Low as 0.6V
100% Duty Cycle in Dropout
Short Circuit Protection
Thermal Fault Protection
<0.1µA Shutdown Current
Programmable Enable Control
APPLICATIONS
ƒ
ƒ
ƒ
ƒ
ƒ
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Cellular and Smart Phones
Microprocessors/DSP Core Supplies
PDAs
MP3 Players
Digital Still and Video Cameras
Portable Instruments
, “MPS”, “Monolithic Power Systems”, and “The Future of Analog IC
Technology” are Registered Trademarks of Monolithic Power Systems, Inc.
EV2105DJ-00A EVALUATION BOARD
Efficiency vs
Load Current
100
90
VIN = 3.3V
EFFICIENCY (%)
80
VIN = 4.2V
70
60
50
40
30
20
10
Dimensions (2.0”X x 2.0”Y x 0.5”Z)
Board Number
MPS IC Number
EV2105DJ-00A
MP2105DJ
12/04, Rev. 1.0
www.MonolithicPower.com
0
10
100
LOAD CURRENT (mA)
1000
MP2105-EC01
1
EV2105DJ-00A – 800mA SYNCHRONOUS BUCK STEP-DOWN CONVERTER
INITIAL RELEASE
EVALUATION BOARD SCHEMATIC
J1
INPUT
2.5V - 6V
IN
R3
NS
OFF ON
VOUT
SW
MP2105
EN
GND
FB
C3
NS
EV2105DJ-00A_S01
EV2105DJ-00A BILL OF MATERIALS
Qty
Ref
Value Description
Package
1
C1
4.7µF
Ceramic Cap, 6.3V, X5R
SM0805
AVX
08056D475KAT2A
1
C2
10µF
Ceramic Cap, 6.3V, X5R
SM0805
AVX
08056D106KAT2A
1
C3
Do Not Stuff
1
J1
Jumper
1
L1
4.7µH 1.15A
SMD
Sumida
CR43-4R7
1
R1
499kΩ Film Res, 1%
SM0805
Yageo
9C08052A3003FK
HFT
1
R2
249kΩ Film Res, 1%
SM0805
Panasonic
ERJ-6ENF1503V
1
R3
Do Not Stuff
1
U1
DC-DC Converter
SOT23-5
MPS
12/04, Rev. 1.0
www.MonolithicPower.com
Manufacturer Manufacturer P/N
MP2105DJ
2
EV2105DJ-00A – 800mA SYNCHRONOUS BUCK STEP-DOWN CONVERTER
INITIAL RELEASE
PRINTED CIRCUIT BOARD LAYOUT
Figure 1—Top Silk Layer
Figure 2—Top Layer
Figure 3—Bottom Silk Layer
Figure 4—Bottom Layer
12/04, Rev. 1.0
www.MonolithicPower.com
3
EV2105DJ-00A – 800mA SYNCHRONOUS BUCK STEP-DOWN CONVERTER
INITIAL RELEASE
QUICK START GUIDE
The output voltage of this board is set to 1.8V. The board layout accommodates most commonly used
inductors and output capacitors.
1. Attach Positive end and Negative end of Load to VOUT and GND pins respectively.
2. Attach Input Voltage 2.5V ≤ VIN ≤ 6V and Input Ground to VIN and GND pins respectively.
3. To enable the MP2105 apply a voltage, 1.5V ≤ VEN ≤ 6V, to the EN pin. To disable the MP2105
apply a voltage, VEN < 0.3V, to the EN pin. The default setting for the jumper J1 on the board
connects VIN to the EN pin. With this configuration, the part will operate without applying any
external voltage to the EN pin.
4. The Output Voltage VOUT can be changed by varying R2. Calculate the new value by formula:
R2 =
R1
⎛ VOUT
⎜⎜
⎝ VFB
⎞
⎟⎟ − 1
⎠
Where VFB = 0.6V and R1 = 499kΩ.
Example:
For VOUT = 2.5V:
R2 =
499kΩ
= 174kΩ
⎛ 2. 5 V ⎞
⎜
⎟ −1
⎝ 0 .6 V ⎠
Therefore, use a 174kΩ standard 1% value.
NOTICE: MPS believes the information in this document to be accurate and reliable. However, it is subject to change without
notice. Contact MPS for current specifications. MPS encourages users of its products to ensure that third party Intellectual
Property rights are not infringed upon when integrating MPS products into any application. MPS cannot assume any legal
responsibility for any said applications.
EV2105DJ-00A Rev. 1.0
Monolithic Power Systems, Inc.
12/2/04
983 University Avenue, Building A, Los Gatos, CA 95032 USA
© 2004 MPS, Inc.
Tel: 408-357-6600 ♦ Fax: 408-357-6601 ♦ www.MonolithicPower.com
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