MIC2250
High Efficiency Low EMI
Boost Regulator
General Description
The MIC2250 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 MIC2250 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 MIC2250 incorporates a pseudo-random
dithering function to reduce EMI levels up to 10dB enabled
by the DITH pin.
The MIC2250 is designed for use with inductor values from
4.7µH to 22µH, and is stable with ceramic capacitors from
1µF to 22µF.
The MIC2250 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 MIC2250’s
internal 34V/2A rated switch, allowing it to power large
loads in a tiny footprint.
The MIC2250 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 32V
•
2A switch 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
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
November 2008
M9999-111708-A
Micrel, Inc.
MIC2250
Ordering Information
Part Number
MIC2250YML
Note:
1.
2.
3.
Pin 1 identifier = “•”.
Overbar (
) may not be to scale.
MLF is GREEN RoHs compliant package. Lead finish is NiPdAu. Mold compound is Halogen Free.
Marking
ZAA
(2)
(1)
Junction Temp. Range
–40° to +125°C
Package
(3)
®
Lead Finish
Pb-Free
8-Pin 2mm x 2mm MLF
Pin Configuration
8-Pin 2mm x 2mm MLF
®
(ML)
(Top View)
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. V
OUT
= 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.
November 2008
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M9999-111708-A
Micrel, Inc.
MIC2250
Absolute Maximum Ratings
(1)
Supply Voltage (V
IN
) .........................................................6V
Switch Voltage (V
SW
)....................................... –0.3V to 34V
Enable Voltage (V
EN
)......................................... –0.3V to V
IN
FB Voltage (V
FB
)...............................................................6V
Switch Current (I
SW
) ......................................................3.5A
Ambient Storage Temperature (Ts) ..........–65°C to +150°C
ESD Rating
(4)
................................................. ESD Sensitive
Operating Ratings
(2)
Supply Voltage (V
IN
)......................................... 2.5V to 5.5V
Enable Voltage (V
EN
).............................................. 0V to V
IN
Junction Temperature (T
J
)
(3)
..................... –40°C to +125°C
Junction Thermal Resistance
2mm x 2mm MLF-8 (θ
JA
) ...................................90°C/W
Electrical Characteristics
(5)
V
IN
= V
EN
= 3.6V; V
DITH
= 0V; V
OUT
= 15V; I
OUT
= 40mA; T
A
= 25°C, unless otherwise noted.
Bold
values indicate
–40°C
≤
T
J
≤
+125°C.
Symbol
V
IN
V
ULVO
I
Q
I
SD
V
FB
I
FB
Tss
t
SW
D
MAX
t
DITH
Parameter
Input Voltage Range
Under-voltage Lockout
Quiescent Current
Shutdown Current
Feedback Voltage
–40°C
≤
T
J
≤
+125°C
Feedback Input Current
Soft Start time
Switch Off-time
Maximum Duty Cycle
Off-time Dithering
Line Regulation
Load Regulation
I
SW
R
ON
I
SW
V
EN
,
V
DITH
I
EN
T
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, T
J(Max)
, the junction-to-ambient thermal resistance,
θ
JA
,
and the ambient temperature, T
A
. 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, 1.5kΩ in series with 100pF.
5. Specification for packaged product only.
6. I
SD
= I
VIN
.
7. Guaranteed by design.
Condition
V
IN
rising
V
FB
= 1.5V (not switching)
V
EN
= 0V,
Note 6
Min
2.5
1.8
Typ
2
52
0.1
Max
5.5
2.4
80
1
1.277
1.29
Units
V
V
µA
µA
V
V
nA
ms
µs
%
%
1.20
1.19
V
FB
= 1.24V
1.24
10
1
PFM Operation
V
IN
= 3.6V
75
V
DITH
= 3.6V. Percentage from nominal.
3V
≤
V
IN
≤
5V
1mA
≤
I
OUT
≤
40mA
Note 7
I
SW
= 200mA
V
EN
= 0V, V
SW
= 10V
Turn ON
Turn OFF
Enable Pin Current
Thermal Shutdown Threshold
Hysteresis
V
EN
= V
IN
= 5.0V
0.1
170
10
1.5
0.4
2
0.9
1.6
87
±20
0.3
0.1
2
0.5
0.01
1
5
2
2
%
%
A
Ω
µA
V
V
µA
°C
°C
Switch Current Limit
Switch ON-resistance
Switch Leakage Current
Logic Input Thresholds
November 2008
3
M9999-111708-A
Micrel, Inc.
MIC2250
Typical Characteristics
November 2008
4
M9999-111708-A
Micrel, Inc.
MIC2250
Functional Characteristics
November 2008
5
M9999-111708-A
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