MIC2251 Datasheet PDF - MICREL

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MIC2251
MICREL

Part Number MIC2251
Description High-Efficiency Low EMI Boost Regulator
Page 13 Pages


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MIC2251
High-Efficiency Low EMI
Boost Regulator
General Description
The MIC2251 is a general purpose DC/DC boost switching
regulator that features low noise, EMI reduction circuitry,
and high efficiency across a wide output current range.
The MIC2251 is optimized for noise-sensitive hand held
battery powered applications. A proprietary control method
allows low ripple across the output voltage and current
ranges. The MIC2251 incorporates a pseudo-random
dithering function to reduce EMI levels up to 10dB enabled
by the DITH pin.
The MIC2251 is designed for use with inductor values from
4.7µH to 22µH, and is stable with ceramic capacitors from
1µF to 22µF.
The MIC2251 attains a high peak efficiency up to 90% at
100mA and excellent light load efficiency of 80% at 1mA.
High power density is achieved with the MIC2251’s
internal 40V/2A rated switch, allowing it to power large
loads in a tiny footprint.
The MIC2251 is available in a 8-pin 2mm x 2mm MLF®
leadless package option with an operating junction
temperature range of –40°C to +125°C.
Data sheets and support documentation can be found on
Micrel’s web site at: www.micrel.com.
Features
Over 80% efficient for a 300:1 load range
2.5V to 5.5V input voltage range
Output voltage adjustable to 37V
2A switch current
52µA (typ) quiescent current
Constant peak current control reduces output ripple
EMI reduction circuitry
Stable with small ceramic capacitors
<1µA shutdown current
UVLO and thermal shutdown
8-pin 2mm x 2mm leadless MLF® package
–40°C to +125°C junction temperature range
Applications
LCD/OLED display bias supply
CCD bias supply
Mobile Phones, PDA, Media Players, GPS PND
Haptic displays
Local 5V, 15V, 24V rail
___________________________________________________________________________________________________________
Typical Application
www.DataSheet4U.com
MLF and MicroLeadFrame are registered trademarks of Amkor Technology, Inc.
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
February 2011
M9999-021511-A



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Micrel, Inc.
MIC2251
Ordering Information
Part Number
MIC2251YML
Marking(1)
ADA(2)
Junction Temp. Range
–40° to +125°C
Package(3)
8-Pin 2mm x 2mm MLF®
Lead Finish
Pb-Free
Note:
1. Pin 1 identifier = “”.
2. Overbar ( ) may not be to scale.
3. MLF® is GREEN RoHs compliant package. Lead finish is NiPdAu. Mold compound is Halogen Free.
Pin Configuration
Pin Description
Pin Number
1
2
3
4
5
6
7
8
EPAD
Pin Name
FB
AGND
PGND
SW
NC
VIN
DITH
EN
GND
Pin Function
Feedback (Input): 1.24V output voltage sense node. VOUT = 1.24V (1 + R1/R2)
Analog Ground. Connect to power ground.
Power Ground.
Switch Node (Input): Internal power NMOS drain.
Not Internally Connected.
Supply (Input): 2.5V to 5.5V input voltage.
Frequency Dithering (Input): Connect this pin high to enable pseudo-random on-
time dithering to reduce EMI. Connect this pin-to-ground to disable this function.
Enable (Input): Logic high enables the regulator. Logic low shuts down the
regulator. Do not leave floating.
Ground (Return): Exposed backside pad. Connect to power ground.
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February 2011
2 M9999-021511-A



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Micrel, Inc.
MIC2251
Absolute Maximum Ratings(1)
Supply Voltage (VIN) .........................................................6V
Switch Voltage (VSW)....................................... –0.3V to 40V
Enable Voltage (VEN)......................................... –0.3V to VIN
FB Voltage (VFB)...............................................................6V
Switch Current (ISW) ......................................................3.5A
Ambient Storage Temperature (Ts) ..........–65°C to +150°C
ESD Rating(4)................................................. ESD Sensitive
Operating Ratings(2)
Supply Voltage (VIN)......................................... 2.5V to 5.5V
EJunnacbtlieonVToeltamgpee(rVatEuNr)e...(.T..J.)..(3..)............................................–..4..0..°.C....t.o0+V1t2o5V°CIN
Junction Thermal Resistance
2mm x 2mm MLF®-8 (θJA)..................................90°C/W
Electrical Characteristics(5)
VIN = VEN = 3.6V; VDITH = 0V; VOUT = 15V; IOUT = 40mA; TA = 25°C, unless otherwise noted. Bold values indicate
–40°C TJ +85°C.
Symbol Parameter
Condition
Min Typ Max
VIN
VULVO
IQ
ISD
Input Voltage Range
Under-voltage Lockout
Quiescent Current
Shutdown Current
VIN rising
VFB = 1.5V (not switching)
VEN = 0V, Note 6
2.5 5.5
1.8 2
2.4
70 120
0.1 1
VFB Feedback Voltage
IFB Feedback Input Current
–40°C TJ +125°C
VFB = 1.24V
1.20 1.24 1.277
1.19
10
1.29
PFM Operation
Tss Soft Start time
1
tSW Switch Off-time
VIN = 3.6V
1.6
DMAX
tDITH
ISW
RON
Maximum Duty Cycle
Off-time Dithering
Line Regulation
Load Regulation
Switch Current Limit
Switch ON-resistance
VDITH = 3.6V. Percentage from nominal.
3V VIN 5V
1mA IOUT 40mA
Note 7
ISW = 200mA
75 87
±20
0.3
0.1
0.9 1.6
0.7
2
2
1
ISW
VEN,
VDITH
Switch Leakage Current
Logic Input Thresholds
VEN = 0V, VSW = 10V
Turn ON
Turn OFF
0.01
1.5
5
0.4
IEN Enable Pin Current
VEN = VIN = 5.0V
T Thermal Shutdown Threshold
0.1 2
130
Hysteresis
15
Units
V
V
µA
µA
V
V
nA
ms
µs
%
%
%
%
A
µA
V
V
µA
°C
°C
Notes:
1. Absolute maximum ratings indicate limits beyond which damage to the component may occur.
2. The device is not guaranteed to function outside its operating rating.
3. The maximum allowable power dissipation is a function of the maximum junction temperature, TJ(Max), the junction-to-ambient thermal resistance, θ JA,
and the ambient temperature, TA. The maximum allowable power dissipation will result in excessive die temperature, and the regulator will go into
thermal shutdown.
4. Devices are ESD sensitive. Handling precautions recommended. Human body model, 1.5kin series with 100pF.
ww5.wS.pDeactifaicSahtieoent4foUr .pcaocmkaged product only.
6. ISD = IVIN.
7. Guaranteed by design.
February 2011
3 M9999-021511-A



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Micrel, Inc.
Typical Characteristics
MIC2251
www.DataSheet4U.com
February 2011
4 M9999-021511-A



MIC2251 datasheet pdf
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