MIC2250
High-Efficiency Low EMI
Boost Regulator
General Description
Features
The MIC2250 is a general purpose DC/DC boost switching
• Over 80% efficient for a 300:1 load range
regulator that features low noise, EMI reduction circuitry,
• 2.5V to 5.5V input voltage range
and high efficiency across a wide output current range.
• Output voltage adjustable to 32V
The MIC2250 is optimized for noise-sensitive hand held
• 52µA (typ) quiescent current
battery powered applications. A proprietary control method
• Constant peak current control reduces output ripple
allows low ripple across the output voltage and current
ranges. The MIC2250 incorporates a pseudo-random
• EMI reduction circuitry
dithering function to reduce EMI levels up to 10dB enabled
• Stable with small ceramic capacitors
by the DITH pin.
• 10V), a high speed diode such as
LS4148 can be more efficient as it has the advantage of
considerably lower leakage currents, especially at higher
temperatures. This will greatly improve light load
efficiency when compared to a Schottky diode.
For example: At 70oC ambient temperature, VIN = 2.5V,
VOUT= 24V at no load.
Input current (Vishay SL04 Schottky) = 2.1mA
Input current (Generic LS4148) = 0.37mA
Figure 2. Efficiency Comparison between Lower
and Higher Inductor Values
Input Capacitor
The boost converter exhibits a triangular current
waveform at its input, so an input capacitor is required to
decouple this waveform and thereby reduce the input
voltage ripple. A 10uF to 22uF ceramic capacitor should
be sufficient for most applications. A minimum input
capacitance of 1uF is recommended. The input capacitor
should be as close as possible to the inductor and the
MIC2250, with short PCB traces for good noise
April 2011
10
M9999-041811-B
Micrel, Inc.
MIC2250
MIC2250 Schematic
Bill of Materials
Item
Part Number
C2012X5R0J106K
C1
Manufacturer
TDK
VJ0805G106KXYAT
Vishay Vitramon(2)
08056D106KAT
AVX(3)
Murata
C2012X5R1E225K
TDK(1)
08053C225MAT
AVX(3)
GRM21R61E225KE36D
Murata(4)
LS4148
Vishay(2)
D1
LS04
VLF5012ST-100M1R0
L1
LPS4018-100
Qty.
Capacitor, 10µF, 6.3V, X5R
1
Capacitor, 2.2µF, 25V, X5R
1
(4)
GRM21BR60J106M
C3
Description
(1)
High Speed Diode, 75V, 300mA
(2)
Vishay
TDK(1)
Coilcraft
1
Schottky Diode, 40V, 1A
10µH
(5)
1
10µH, 10%
CDRH4D28NP-100NC
Sumida(6)
R1
CRCW06031004FKEYE3
Vishay Dale(2)
Resistor, 1M, 1%. 1/16W, Size 0603
1
R2
CRCW06039012FKEYE3
Vishay Dale(2)
Resistor, 90.1k, 1%. 1/16W, Size 0603
1
High-Efficiency Low EMI Boost Regulator
1
U1
MIC2250YML
Micrel, Inc.
10µH, 1.26A
(7)
Notes:
1. TDK: www.tdk.com.
2. Vishay: www.vishay.com.
3. AVX: www.avx.com.
4. Murata: www.murata.com.
5. Coilcraft: www.coilcraft.com.
6. Sumida: www.sumida.com.
7. Micrel, Inc.: www.micrel.com.
April 2011
11
M9999-041811-B
Micrel, Inc.
MIC2250
PCB Layout Recommendations
Top Layer
Bottom Layer
April 2011
12
M9999-041811-B
Micrel, Inc.
MIC2250
Package Information
8-Pin 2mm x 2mm MLF® (ML)
April 2011
13
M9999-041811-B
Micrel, Inc.
MIC2250
5-Pin Thin SOT-23 (D5)
MICREL, INC. 2180 FORTUNE DRIVE SAN JOSE, CA 95131 USA
TEL +1 (408) 944-0800 FAX +1 (408) 474-1000 WEB http://www.micrel.com
Micrel makes no representations or warranties with respect to the accuracy or completeness of the information furnished in this data sheet. This
information is not intended as a warranty and Micrel does not assume responsibility for its use. Micrel reserves the right to change circuitry,
specifications and descriptions at any time without notice. No license, whether express, implied, arising by estoppel or otherwise, to any intellectual
property rights is granted by this document. Except as provided in Micrel’s terms and conditions of sale for such products, Micrel assumes no liability
whatsoever, and Micrel disclaims any express or implied warranty relating to the sale and/or use of Micrel products including liability or warranties
relating to fitness for a particular purpose, merchantability, or infringement of any patent, copyright or other intellectual property right.
Micrel Products are not designed or authorized for use as components in life support appliances, devices or systems where malfunction of a product
can reasonably be expected to result in personal injury. Life support devices or systems are devices or systems that (a) are intended for surgical
implant into the body or (b) support or sustain life, and whose failure to perform can be reasonably expected to result in a significant injury to the user. A
Purchaser’s use or sale of Micrel Products for use in life support appliances, devices or systems is a Purchaser’s own risk and Purchaser agrees to fully
indemnify Micrel for any damages resulting from such use or sale.
© 2008 Micrel, Incorporated.
April 2011
14
M9999-041811-B
